Many: use stdin support of file_case::muxer()

[s-roff.git] / src / roff / troff / input.cpp

// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992, 2000, 2001, 2002, 2003, 2004, 2005,
                 2006, 2007, 2008
   Free Software Foundation, Inc.
     Written by James Clark (jjc@jclark.com)

This file is part of groff.

groff is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.

groff is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with groff; see the file COPYING.  If not, write to the Free Software
Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */

#define DEBUGGING

#include "troff.h"
#include "dictionary.h"
#include "hvunits.h"
#include "stringclass.h"
#include "mtsm.h"
#include "env.h"
#include "file_case.h"
#include "request.h"
#include "node.h"
#include "token.h"
#include "div.h"
#include "reg.h"
#include "font.h"
#include "charinfo.h"
#include "macropath.h"
#include "input.h"
#include "defs.h"
#include "unicode.h"

// Needed for getpid() and isatty()
#include "posix.h"

#include "nonposix.h"

#ifdef NEED_DECLARATION_PUTENV
extern "C" {
  int putenv(const char *);
}
#endif /* NEED_DECLARATION_PUTENV */

#define MACRO_PREFIX "tmac."
#define MACRO_POSTFIX ".tmac"
#define INITIAL_STARTUP_FILE "troffrc"
#define FINAL_STARTUP_FILE   "troffrc-end"
#define DEFAULT_INPUT_STACK_LIMIT 1000

#ifndef DEFAULT_WARNING_MASK
// warnings that are enabled by default
#define DEFAULT_WARNING_MASK \
     (WARN_CHAR|WARN_NUMBER|WARN_BREAK|WARN_SPACE|WARN_FONT)
#endif

// initial size of buffer for reading names; expanded as necessary
#define ABUF_SIZE 16

extern "C" const char *program_name;
extern "C" const char *Version_string;

#ifdef COLUMN
void init_column_requests();
#endif /* COLUMN */

static node *read_draw_node();
static void read_color_draw_node(token &);
static void push_token(const token &);
void copy_file();
#ifdef COLUMN
void vjustify();
#endif /* COLUMN */
void transparent_file();

token tok;
int break_flag = 0;
int color_flag = 1;             // colors are on by default
static int backtrace_flag = 0;
#ifndef POPEN_MISSING
char *pipe_command = 0;
#endif
charinfo *charset_table[256];
unsigned char hpf_code_table[256];

static int warning_mask = DEFAULT_WARNING_MASK;
static int inhibit_errors = 0;
static int ignoring = 0;

static void enable_warning(const char *);
static void disable_warning(const char *);

static int escape_char = '\\';
static symbol end_macro_name;
static symbol blank_line_macro_name;
static int compatible_flag = 0;
int ascii_output_flag = 0;
int suppress_output_flag = 0;
int is_html = 0;
int begin_level = 0;            // number of nested \O escapes

int have_input = 0;             // whether \f, \F, \D'F...', \H, \m, \M,
                                // \O[345], \R, \s, or \S has been processed
                                // in token::next()
int old_have_input = 0;         // value of have_input right before \n
int tcommand_flag = 0;
int unsafe_flag = 0;            // safer by default

int have_string_arg = 0;        // whether we have \*[foo bar...]

double spread_limit = -3.0 - 1.0;       // negative means deactivated

double warn_scale;
char warn_scaling_indicator;
int debug_state = 0;            // turns on debugging of the html troff state

search_path *mac_path = &safer_macro_path;

// Defaults to the current directory.
search_path include_search_path(0, 0, 0, 1);

static int get_copy(node**, int = 0, int = 0);
static void copy_mode_error(const char *,
                            const errarg & = empty_errarg,
                            const errarg & = empty_errarg,
                            const errarg & = empty_errarg);

enum read_mode { ALLOW_EMPTY, WITH_ARGS, NO_ARGS };
static symbol read_escape_name(read_mode = NO_ARGS);
static symbol read_long_escape_name(read_mode = NO_ARGS);
static void interpolate_string(symbol);
static void interpolate_string_with_args(symbol);
static void interpolate_macro(symbol, int = 0);
static void interpolate_number_format(symbol);
static void interpolate_environment_variable(symbol);

static symbol composite_glyph_name(symbol);
static void interpolate_arg(symbol);
static request_or_macro *lookup_request(symbol);
static int get_delim_number(units *, unsigned char);
static int get_delim_number(units *, unsigned char, units);
static symbol do_get_long_name(int, char);
static int get_line_arg(units *res, unsigned char si, charinfo **cp);
static int read_size(int *);
static symbol get_delim_name();
static void init_registers();
static void trapping_blank_line();

class input_iterator;
input_iterator *make_temp_iterator(const char *);
const char *input_char_description(int);

void process_input_stack();
void chop_macro();              // declare to avoid friend name injection


void set_escape_char()
{
  if (has_arg()) {
    if (tok.ch() == 0) {
      error("bad escape character");
      escape_char = '\\';
    }
    else
      escape_char = tok.ch();
  }
  else
    escape_char = '\\';
  skip_line();
}

void escape_off()
{
  escape_char = 0;
  skip_line();
}

static int saved_escape_char = '\\';

void save_escape_char()
{
  saved_escape_char = escape_char;
  skip_line();
}

void restore_escape_char()
{
  escape_char = saved_escape_char;
  skip_line();
}

struct arg_list;

class input_iterator {
public:
  input_iterator();
  input_iterator(int is_div);
  virtual ~input_iterator() {}
  int get(node **);
  friend class input_stack;
  int is_diversion;
  statem *diversion_state;
protected:
  const unsigned char *ptr;
  const unsigned char *eptr;
  input_iterator *next;
private:
  virtual int fill(node **);
  virtual int peek();
  virtual int has_args() { return 0; }
  virtual int nargs() { return 0; }
  virtual input_iterator *get_arg(int) { return 0; }
  virtual arg_list *get_arg_list() { return 0; }
  virtual symbol get_macro_name() { return NULL_SYMBOL; }
  virtual int space_follows_arg(int) { return 0; }
  virtual int get_break_flag() { return 0; }
  virtual int get_location(int, const char **, int *) { return 0; }
  virtual void backtrace() {}
  virtual int set_location(const char *, int) { return 0; }
  virtual int next_file(file_case *, const char *) { return 0; }
  virtual void shift(int) {}
  virtual int is_boundary() {return 0; }
  virtual int is_file() { return 0; }
  virtual int is_macro() { return 0; }
  virtual void save_compatible_flag(int) {}
  virtual int get_compatible_flag() { return 0; }
};

input_iterator::input_iterator()
: is_diversion(0), ptr(0), eptr(0)
{
}

input_iterator::input_iterator(int is_div)
: is_diversion(is_div), ptr(0), eptr(0)
{
}

int input_iterator::fill(node **)
{
  return EOF;
}

int input_iterator::peek()
{
  return EOF;
}

inline int input_iterator::get(node **p)
{
  return ptr < eptr ? *ptr++ : fill(p);
}

class input_boundary : public input_iterator {
public:
  int is_boundary() { return 1; }
};

class input_return_boundary : public input_iterator {
public:
  int is_boundary() { return 2; }
};

class file_iterator : public input_iterator {
  file_case *_fcp;
  int lineno;
  const char *filename;
  int newline_flag;
  int seen_escape;
  enum { BUF_SIZE = 512 };
  unsigned char buf[BUF_SIZE];
  void close();
public:
  file_iterator(file_case *, const char *);
  ~file_iterator();
  int fill(node **);
  int peek();
  int get_location(int, const char **, int *);
  void backtrace();
  int set_location(const char *, int);
  int next_file(file_case *, const char *);
  int is_file();
};

file_iterator::file_iterator(file_case *fcp, const char *fn)
: _fcp(fcp), lineno(1), filename(fn), newline_flag(0), seen_escape(0)
{
  if ((font::use_charnames_in_special) && (fn != 0)) {
    if (!the_output)
      init_output();
    the_output->put_filename(fn, _fcp->is_pipe());
  }
}

file_iterator::~file_iterator()
{
  if (_fcp != NULL)
    delete _fcp;
}

void file_iterator::close()
{
  if (_fcp != NULL) {
    delete _fcp;
    _fcp = NULL;
  }
}

int file_iterator::is_file()
{
  return 1;
}

int file_iterator::next_file(file_case *fcp, const char *s)
{
  close();
  _fcp = fcp;
  filename = s;
  lineno = 1;
  newline_flag = 0;
  seen_escape = 0;
  ptr = 0;
  eptr = 0;
  return 1;
}

int file_iterator::fill(node **)
{
  if (newline_flag)
    lineno++;
  newline_flag = 0;
  unsigned char *p = buf;
  ptr = p;
  unsigned char *e = p + BUF_SIZE;
  while (p < e) {
    int c = _fcp->get_c();
    if (c == EOF)
      break;
    if (invalid_input_char(c))
      warning(WARN_INPUT, "invalid input character code %1", int(c));
    else {
      *p++ = c;
      if (c == '\n') {
        seen_escape = 0;
        newline_flag = 1;
        break;
      }
      seen_escape = (c == '\\');
    }
  }
  if (p > buf) {
    eptr = p;
    return *ptr++;
  }
  else {
    eptr = p;
    return EOF;
  }
}

int file_iterator::peek()
{
  int c = _fcp->get_c();
  while (invalid_input_char(c)) {
    warning(WARN_INPUT, "invalid input character code %1", int(c));
    c = _fcp->get_c();
  }
  if (c != EOF)
    _fcp->unget_c(c);
  return c;
}

int file_iterator::get_location(int /*allow_macro*/,
                                const char **filenamep, int *linenop)
{
  *linenop = lineno;
  if (filename != 0 && strcmp(filename, "-") == 0)
    *filenamep = "<standard input>";
  else
    *filenamep = filename;
  return 1;
}

void file_iterator::backtrace()
{
  errprint("%1:%2: backtrace: %3 `%1'\n", filename, lineno,
           _fcp->is_pipe() ? "process" : "file");
}

int file_iterator::set_location(const char *f, int ln)
{
  if (f) {
    filename = f;
    if (!the_output)
      init_output();
    the_output->put_filename(f, 0);
  }
  lineno = ln;
  return 1;
}

input_iterator nil_iterator;

class input_stack {
public:
  static int get(node **);
  static int peek();
  static void push(input_iterator *);
  static input_iterator *get_arg(int);
  static arg_list *get_arg_list();
  static symbol get_macro_name();
  static int space_follows_arg(int);
  static int get_break_flag();
  static int nargs();
  static int get_location(int, const char **, int *);
  static int set_location(const char *, int);
  static void backtrace();
  static void backtrace_all();
  static void next_file(file_case *, const char *);
  static void end_file();
  static void shift(int n);
  static void add_boundary();
  static void add_return_boundary();
  static int is_return_boundary();
  static void remove_boundary();
  static int get_level();
  static int get_div_level();
  static void increase_level();
  static void decrease_level();
  static void clear();
  static void pop_macro();
  static void save_compatible_flag(int);
  static int get_compatible_flag();
  static statem *get_diversion_state();
  static void check_end_diversion(input_iterator *t);
  static int limit;
  static int div_level;
  static statem *diversion_state;
private:
  static input_iterator *top;
  static int level;
  static int finish_get(node **);
  static int finish_peek();
};

input_iterator *input_stack::top = &nil_iterator;
int input_stack::level = 0;
int input_stack::limit = DEFAULT_INPUT_STACK_LIMIT;
int input_stack::div_level = 0;
statem *input_stack::diversion_state = NULL;
int suppress_push=0;


inline int input_stack::get_level()
{
  return level;
}

inline void input_stack::increase_level()
{
  level++;
}

inline void input_stack::decrease_level()
{
  level--;
}

inline int input_stack::get_div_level()
{
  return div_level;
}

inline int input_stack::get(node **np)
{
  int res = (top->ptr < top->eptr) ? *top->ptr++ : finish_get(np);
  if (res == '\n') {
    old_have_input = have_input;
    have_input = 0;
  }
  return res;
}

int input_stack::finish_get(node **np)
{
  for (;;) {
    int c = top->fill(np);
    if (c != EOF || top->is_boundary())
      return c;
    if (top == &nil_iterator)
      break;
    input_iterator *tem = top;
    check_end_diversion(tem);
#if defined(DEBUGGING)
    if (debug_state)
      if (tem->is_diversion)
        fprintf(stderr,
                "in diversion level = %d\n", input_stack::get_div_level());
#endif
    top = top->next;
    level--;
    delete tem;
    if (top->ptr < top->eptr)
      return *top->ptr++;
  }
  assert(level == 0);
  return EOF;
}

inline int input_stack::peek()
{
  return (top->ptr < top->eptr) ? *top->ptr : finish_peek();
}

void input_stack::check_end_diversion(input_iterator *t)
{
  if (t->is_diversion) {
    div_level--;
    diversion_state = t->diversion_state;
  }
}

int input_stack::finish_peek()
{
  for (;;) {
    int c = top->peek();
    if (c != EOF || top->is_boundary())
      return c;
    if (top == &nil_iterator)
      break;
    input_iterator *tem = top;
    check_end_diversion(tem);
    top = top->next;
    level--;
    delete tem;
    if (top->ptr < top->eptr)
      return *top->ptr;
  }
  assert(level == 0);
  return EOF;
}

void input_stack::add_boundary()
{
  push(new input_boundary);
}

void input_stack::add_return_boundary()
{
  push(new input_return_boundary);
}

int input_stack::is_return_boundary()
{
  return top->is_boundary() == 2;
}

void input_stack::remove_boundary()
{
  assert(top->is_boundary());
  input_iterator *temp = top->next;
  check_end_diversion(top);

  delete top;
  top = temp;
  level--;
}

void input_stack::push(input_iterator *in)
{
  if (in == 0)
    return;
  if (++level > limit && limit > 0)
    fatal("input stack limit exceeded (probable infinite loop)");
  in->next = top;
  top = in;
  if (top->is_diversion) {
    div_level++;
    in->diversion_state = diversion_state;
    diversion_state = curenv->construct_state(0);
#if defined(DEBUGGING)
    if (debug_state) {
      curenv->dump_troff_state();
      fflush(stderr);
    }
#endif
  }
#if defined(DEBUGGING)
  if (debug_state)
    if (top->is_diversion) {
      fprintf(stderr,
              "in diversion level = %d\n", input_stack::get_div_level());
      fflush(stderr);
    }
#endif
}

statem *get_diversion_state()
{
  return input_stack::get_diversion_state();
}

statem *input_stack::get_diversion_state()
{
  if (diversion_state == NULL)
    return NULL;
  else
    return new statem(diversion_state);
}

input_iterator *input_stack::get_arg(int i)
{
  input_iterator *p;
  for (p = top; p != 0; p = p->next)
    if (p->has_args())
      return p->get_arg(i);
  return 0;
}

arg_list *input_stack::get_arg_list()
{
  input_iterator *p;
  for (p = top; p != 0; p = p->next)
    if (p->has_args())
      return p->get_arg_list();
  return 0;
}

symbol input_stack::get_macro_name()
{
  input_iterator *p;
  for (p = top; p != 0; p = p->next)
    if (p->has_args())
      return p->get_macro_name();
  return NULL_SYMBOL;
}

int input_stack::space_follows_arg(int i)
{
  input_iterator *p;
  for (p = top; p != 0; p = p->next)
    if (p->has_args())
      return p->space_follows_arg(i);
  return 0;
}

int input_stack::get_break_flag()
{
  return top->get_break_flag();
}

void input_stack::shift(int n)
{
  for (input_iterator *p = top; p; p = p->next)
    if (p->has_args()) {
      p->shift(n);
      return;
    }
}

int input_stack::nargs()
{
  for (input_iterator *p =top; p != 0; p = p->next)
    if (p->has_args())
      return p->nargs();
  return 0;
}

int input_stack::get_location(int allow_macro, const char **filenamep, int *linenop)
{
  for (input_iterator *p = top; p; p = p->next)
    if (p->get_location(allow_macro, filenamep, linenop))
      return 1;
  return 0;
}

void input_stack::backtrace()
{
  const char *f;
  int n;
  // only backtrace down to (not including) the topmost file
  for (input_iterator *p = top;
       p && !p->get_location(0, &f, &n);
       p = p->next)
    p->backtrace();
}

void input_stack::backtrace_all()
{
  for (input_iterator *p = top; p; p = p->next)
    p->backtrace();
}

int input_stack::set_location(const char *filename, int lineno)
{
  for (input_iterator *p = top; p; p = p->next)
    if (p->set_location(filename, lineno))
      return 1;
  return 0;
}

void input_stack::next_file(file_case *fcp, const char *s)
{
  input_iterator **pp;
  for (pp = &top; *pp != &nil_iterator; pp = &(*pp)->next)
    if ((*pp)->next_file(fcp, s))
      return;
  if (++level > limit && limit > 0)
    fatal("input stack limit exceeded");
  *pp = new file_iterator(fcp, s);
  (*pp)->next = &nil_iterator;
}

void input_stack::end_file()
{
  for (input_iterator **pp = &top; *pp != &nil_iterator; pp = &(*pp)->next)
    if ((*pp)->is_file()) {
      input_iterator *tem = *pp;
      check_end_diversion(tem);
      *pp = (*pp)->next;
      delete tem;
      level--;
      return;
    }
}

void input_stack::clear()
{
  int nboundaries = 0;
  while (top != &nil_iterator) {
    if (top->is_boundary())
      nboundaries++;
    input_iterator *tem = top;
    check_end_diversion(tem);
    top = top->next;
    level--;
    delete tem;
  }
  // Keep while_request happy.
  for (; nboundaries > 0; --nboundaries)
    add_return_boundary();
}

void input_stack::pop_macro()
{
  int nboundaries = 0;
  int is_macro = 0;
  do {
    if (top->next == &nil_iterator)
      break;
    if (top->is_boundary())
      nboundaries++;
    is_macro = top->is_macro();
    input_iterator *tem = top;
    check_end_diversion(tem);
    top = top->next;
    level--;
    delete tem;
  } while (!is_macro);
  // Keep while_request happy.
  for (; nboundaries > 0; --nboundaries)
    add_return_boundary();
}

inline void input_stack::save_compatible_flag(int f)
{
  top->save_compatible_flag(f);
}

inline int input_stack::get_compatible_flag()
{
  return top->get_compatible_flag();
}

void backtrace_request()
{
  input_stack::backtrace_all();
  fflush(stderr);
  skip_line();
}

void next_file()
{
  symbol nm = get_long_name();
  while (!tok.newline() && !tok.eof())
    tok.next();
  if (nm.is_null())
    input_stack::end_file();
  else {
    file_case *fcp = include_search_path.open_file_cautious(nm.contents(),
        fcp->fc_const_path);
    if (fcp != NULL) {
      input_stack::next_file(fcp, nm.contents());
      delete fcp;
    } else
      error("can't open `%1': %2", nm.contents(), strerror(errno));
  }
  tok.next();
}

void shift()
{
  int n;
  if (!has_arg() || !get_integer(&n))
    n = 1;
  input_stack::shift(n);
  skip_line();
}

static char get_char_for_escape_name(int allow_space = 0)
{
  int c = get_copy(0, 0, 1);
  switch (c) {
  case EOF:
    copy_mode_error("end of input in escape name");
    return '\0';
  default:
    if (!invalid_input_char(c))
      break;
    // fall through
  case '\n':
    if (c == '\n')
      input_stack::push(make_temp_iterator("\n"));
    // fall through
  case ' ':
    if (c == ' ' && allow_space)
      break;
    // fall through
  case '\t':
  case '\001':
  case '\b':
    copy_mode_error("%1 is not allowed in an escape name",
                    input_char_description(c));
    return '\0';
  }
  return c;
}

static symbol read_two_char_escape_name()
{
  char buf[3];
  buf[0] = get_char_for_escape_name();
  if (buf[0] != '\0') {
    buf[1] = get_char_for_escape_name();
    if (buf[1] == '\0')
      buf[0] = 0;
    else
      buf[2] = 0;
  }
  return symbol(buf);
}

static symbol read_long_escape_name(read_mode mode)
{
  int start_level = input_stack::get_level();
  char abuf[ABUF_SIZE];
  char *buf = abuf;
  int buf_size = ABUF_SIZE;
  int i = 0;
  char c;
  int have_char = 0;
  for (;;) {
    c = get_char_for_escape_name(have_char && mode == WITH_ARGS);
    if (c == 0) {
      if (buf != abuf)
        a_delete buf;
      return NULL_SYMBOL;
    }
    have_char = 1;
    if (mode == WITH_ARGS && c == ' ')
      break;
    if (i + 2 > buf_size) {
      if (buf == abuf) {
        buf = new char[ABUF_SIZE*2];
        memcpy(buf, abuf, buf_size);
        buf_size = ABUF_SIZE*2;
      }
      else {
        char *old_buf = buf;
        buf = new char[buf_size*2];
        memcpy(buf, old_buf, buf_size);
        buf_size *= 2;
        a_delete old_buf;
      }
    }
    if (c == ']' && input_stack::get_level() == start_level)
      break;
    buf[i++] = c;
  }
  buf[i] = 0;
  if (c == ' ')
    have_string_arg = 1;
  if (buf == abuf) {
    if (i == 0) {
      if (mode != ALLOW_EMPTY)
        copy_mode_error("empty escape name");
      return EMPTY_SYMBOL;
    }
    return symbol(abuf);
  }
  else {
    symbol s(buf);
    a_delete buf;
    return s;
  }
}

static symbol read_escape_name(read_mode mode)
{
  char c = get_char_for_escape_name();
  if (c == 0)
    return NULL_SYMBOL;
  if (c == '(')
    return read_two_char_escape_name();
  if (c == '[' && !compatible_flag)
    return read_long_escape_name(mode);
  char buf[2];
  buf[0] = c;
  buf[1] = '\0';
  return symbol(buf);
}

static symbol read_increment_and_escape_name(int *incp)
{
  char c = get_char_for_escape_name();
  switch (c) {
  case 0:
    *incp = 0;
    return NULL_SYMBOL;
  case '(':
    *incp = 0;
    return read_two_char_escape_name();
  case '+':
    *incp = 1;
    return read_escape_name();
  case '-':
    *incp = -1;
    return read_escape_name();
  case '[':
    if (!compatible_flag) {
      *incp = 0;
      return read_long_escape_name();
    }
    break;
  }
  *incp = 0;
  char buf[2];
  buf[0] = c;
  buf[1] = '\0';
  return symbol(buf);
}

static int get_copy(node **nd, int defining, int handle_escape_E)
{
  for (;;) {
    int c = input_stack::get(nd);
    if (c == PUSH_GROFF_MODE) {
      input_stack::save_compatible_flag(compatible_flag);
      compatible_flag = 0;
      continue;
    }
    if (c == PUSH_COMP_MODE) {
      input_stack::save_compatible_flag(compatible_flag);
      compatible_flag = 1;
      continue;
    }
    if (c == POP_GROFFCOMP_MODE) {
      compatible_flag = input_stack::get_compatible_flag();
      continue;
    }
    if (c == BEGIN_QUOTE) {
      input_stack::increase_level();
      continue;
    }
    if (c == END_QUOTE) {
      input_stack::decrease_level();
      continue;
    }
    if (c == DOUBLE_QUOTE)
      continue;
    if (c == ESCAPE_E && handle_escape_E)
      c = escape_char;
    if (c == ESCAPE_NEWLINE) {
      if (defining)
        return c;
      do {
        c = input_stack::get(nd);
      } while (c == ESCAPE_NEWLINE);
    }
    if (c != escape_char || escape_char <= 0)
      return c;
  again:
    c = input_stack::peek();
    switch(c) {
    case 0:
      return escape_char;
    case '"':
      (void)input_stack::get(0);
      while ((c = input_stack::get(0)) != '\n' && c != EOF)
        ;
      return c;
    case '#':                   // Like \" but newline is ignored.
      (void)input_stack::get(0);
      while ((c = input_stack::get(0)) != '\n')
        if (c == EOF)
          return EOF;
      break;
    case '$':
      {
        (void)input_stack::get(0);
        symbol s = read_escape_name();
        if (!(s.is_null() || s.is_empty()))
          interpolate_arg(s);
        break;
      }
    case '*':
      {
        (void)input_stack::get(0);
        symbol s = read_escape_name(WITH_ARGS);
        if (!(s.is_null() || s.is_empty())) {
          if (have_string_arg) {
            have_string_arg = 0;
            interpolate_string_with_args(s);
          }
          else
            interpolate_string(s);
        }
        break;
      }
    case 'a':
      (void)input_stack::get(0);
      return '\001';
    case 'e':
      (void)input_stack::get(0);
      return ESCAPE_e;
    case 'E':
      (void)input_stack::get(0);
      if (handle_escape_E)
        goto again;
      return ESCAPE_E;
    case 'n':
      {
        (void)input_stack::get(0);
        int inc;
        symbol s = read_increment_and_escape_name(&inc);
        if (!(s.is_null() || s.is_empty()))
          interpolate_number_reg(s, inc);
        break;
      }
    case 'g':
      {
        (void)input_stack::get(0);
        symbol s = read_escape_name();
        if (!(s.is_null() || s.is_empty()))
          interpolate_number_format(s);
        break;
      }
    case 't':
      (void)input_stack::get(0);
      return '\t';
    case 'V':
      {
        (void)input_stack::get(0);
        symbol s = read_escape_name();
        if (!(s.is_null() || s.is_empty()))
          interpolate_environment_variable(s);
        break;
      }
    case '\n':
      (void)input_stack::get(0);
      if (defining)
        return ESCAPE_NEWLINE;
      break;
    case ' ':
      (void)input_stack::get(0);
      return ESCAPE_SPACE;
    case '~':
      (void)input_stack::get(0);
      return ESCAPE_TILDE;
    case ':':
      (void)input_stack::get(0);
      return ESCAPE_COLON;
    case '|':
      (void)input_stack::get(0);
      return ESCAPE_BAR;
    case '^':
      (void)input_stack::get(0);
      return ESCAPE_CIRCUMFLEX;
    case '{':
      (void)input_stack::get(0);
      return ESCAPE_LEFT_BRACE;
    case '}':
      (void)input_stack::get(0);
      return ESCAPE_RIGHT_BRACE;
    case '`':
      (void)input_stack::get(0);
      return ESCAPE_LEFT_QUOTE;
    case '\'':
      (void)input_stack::get(0);
      return ESCAPE_RIGHT_QUOTE;
    case '-':
      (void)input_stack::get(0);
      return ESCAPE_HYPHEN;
    case '_':
      (void)input_stack::get(0);
      return ESCAPE_UNDERSCORE;
    case 'c':
      (void)input_stack::get(0);
      return ESCAPE_c;
    case '!':
      (void)input_stack::get(0);
      return ESCAPE_BANG;
    case '?':
      (void)input_stack::get(0);
      return ESCAPE_QUESTION;
    case '&':
      (void)input_stack::get(0);
      return ESCAPE_AMPERSAND;
    case ')':
      (void)input_stack::get(0);
      return ESCAPE_RIGHT_PARENTHESIS;
    case '.':
      (void)input_stack::get(0);
      return c;                 
    case '%':
      (void)input_stack::get(0);
      return ESCAPE_PERCENT;
    default:
      if (c == escape_char) {
        (void)input_stack::get(0);
        return c;
      }
      else
        return escape_char;
    }
  }
}

class non_interpreted_char_node : public node {
  unsigned char c;
public:
  non_interpreted_char_node(unsigned char);
  node *copy();
  int interpret(macro *);
  int same(node *);
  const char *type();
  int force_tprint();
  int is_tag();
};

int non_interpreted_char_node::same(node *nd)
{
  return c == ((non_interpreted_char_node *)nd)->c;
}

const char *non_interpreted_char_node::type()
{
  return "non_interpreted_char_node";
}

int non_interpreted_char_node::force_tprint()
{
  return 0;
}

int non_interpreted_char_node::is_tag()
{
  return 0;
}

non_interpreted_char_node::non_interpreted_char_node(unsigned char n) : c(n)
{
  assert(n != 0);
}

node *non_interpreted_char_node::copy()
{
  return new non_interpreted_char_node(c);
}

int non_interpreted_char_node::interpret(macro *mac)
{
  mac->append(c);
  return 1;
}

static void do_width();
static node *do_non_interpreted();
static node *do_special();
static node *do_suppress(symbol nm);
static void do_register();

dictionary color_dictionary(501);

static color *lookup_color(symbol nm)
{
  assert(!nm.is_null());
  if (nm == default_symbol)
    return &default_color;
  color *c = (color *)color_dictionary.lookup(nm);
  if (c == 0)
    warning(WARN_COLOR, "color `%1' not defined", nm.contents());
  return c;
}

void do_glyph_color(symbol nm)
{
  if (nm.is_null())
    return;
  if (nm.is_empty())
    curenv->set_glyph_color(curenv->get_prev_glyph_color());
  else {
    color *tem = lookup_color(nm);
    if (tem)
      curenv->set_glyph_color(tem);
    else
      (void)color_dictionary.lookup(nm, new color(nm));
  }
}

void do_fill_color(symbol nm)
{
  if (nm.is_null())
    return;
  if (nm.is_empty())
    curenv->set_fill_color(curenv->get_prev_fill_color());
  else {
    color *tem = lookup_color(nm);
    if (tem)
      curenv->set_fill_color(tem);
    else
      (void)color_dictionary.lookup(nm, new color(nm));
  }
}

static unsigned int get_color_element(const char *scheme, const char *col)
{
  units val;
  if (!get_number(&val, 'f')) {
    warning(WARN_COLOR, "%1 in %2 definition set to 0", col, scheme);
    tok.next();
    return 0;
  }
  if (val < 0) {
    warning(WARN_RANGE, "%1 cannot be negative: set to 0", col);
    return 0;
  }
  if (val > color::MAX_COLOR_VAL+1) {
    warning(WARN_RANGE, "%1 cannot be greater than 1", col);
    // we change 0x10000 to 0xffff
    return color::MAX_COLOR_VAL;
  }
  return (unsigned int)val;
}

static color *read_rgb(char end = 0)
{
  symbol component = do_get_long_name(0, end);
  if (component.is_null()) {
    warning(WARN_COLOR, "missing rgb color values");
    return 0;
  }
  const char *s = component.contents();
  color *col = new color;
  if (*s == '#') {
    if (!col->read_rgb(s)) {
      warning(WARN_COLOR, "expecting rgb color definition not `%1'", s);
      delete col;
      return 0;
    }
  }
  else {
    if (!end)
      input_stack::push(make_temp_iterator(" "));
    input_stack::push(make_temp_iterator(s));
    tok.next();
    unsigned int r = get_color_element("rgb color", "red component");
    unsigned int g = get_color_element("rgb color", "green component");
    unsigned int b = get_color_element("rgb color", "blue component");
    col->set_rgb(r, g, b);
  }
  return col;
}

static color *read_cmy(char end = 0)
{
  symbol component = do_get_long_name(0, end);
  if (component.is_null()) {
    warning(WARN_COLOR, "missing cmy color values");
    return 0;
  }
  const char *s = component.contents();
  color *col = new color;
  if (*s == '#') {
    if (!col->read_cmy(s)) {
      warning(WARN_COLOR, "expecting cmy color definition not `%1'", s);
      delete col;
      return 0;
    }
  }
  else {
    if (!end)
      input_stack::push(make_temp_iterator(" "));
    input_stack::push(make_temp_iterator(s));
    tok.next();
    unsigned int c = get_color_element("cmy color", "cyan component");
    unsigned int m = get_color_element("cmy color", "magenta component");
    unsigned int y = get_color_element("cmy color", "yellow component");
    col->set_cmy(c, m, y);
  }
  return col;
}

static color *read_cmyk(char end = 0)
{
  symbol component = do_get_long_name(0, end);
  if (component.is_null()) {
    warning(WARN_COLOR, "missing cmyk color values");
    return 0;
  }
  const char *s = component.contents();
  color *col = new color;
  if (*s == '#') {
    if (!col->read_cmyk(s)) {
      warning(WARN_COLOR, "`expecting a cmyk color definition not `%1'", s);
      delete col;
      return 0;
    }
  }
  else {
    if (!end)
      input_stack::push(make_temp_iterator(" "));
    input_stack::push(make_temp_iterator(s));
    tok.next();
    unsigned int c = get_color_element("cmyk color", "cyan component");
    unsigned int m = get_color_element("cmyk color", "magenta component");
    unsigned int y = get_color_element("cmyk color", "yellow component");
    unsigned int k = get_color_element("cmyk color", "black component");
    col->set_cmyk(c, m, y, k);
  }
  return col;
}

static color *read_gray(char end = 0)
{
  symbol component = do_get_long_name(0, end);
  if (component.is_null()) {
    warning(WARN_COLOR, "missing gray values");
    return 0;
  }
  const char *s = component.contents();
  color *col = new color;
  if (*s == '#') {
    if (!col->read_gray(s)) {
      warning(WARN_COLOR, "`expecting a gray definition not `%1'", s);
      delete col;
      return 0;
    }
  }
  else {
    if (!end)
      input_stack::push(make_temp_iterator("\n"));
    input_stack::push(make_temp_iterator(s));
    tok.next();
    unsigned int g = get_color_element("gray", "gray value");
    col->set_gray(g);
  }
  return col;
}

static void activate_color()
{
  int n;
  if (has_arg() && get_integer(&n))
    color_flag = n != 0;
  else
    color_flag = 1;
  skip_line();
}

static void define_color()
{
  symbol color_name = get_long_name(1);
  if (color_name.is_null()) {
    skip_line();
    return;
  }
  if (color_name == default_symbol) {
    warning(WARN_COLOR, "default color can't be redefined");
    skip_line();
    return;
  }
  symbol style = get_long_name(1);
  if (style.is_null()) {
    skip_line();
    return;
  }
  color *col;
  if (strcmp(style.contents(), "rgb") == 0)
    col = read_rgb();
  else if (strcmp(style.contents(), "cmyk") == 0)
    col = read_cmyk();
  else if (strcmp(style.contents(), "gray") == 0)
    col = read_gray();
  else if (strcmp(style.contents(), "grey") == 0)
    col = read_gray();
  else if (strcmp(style.contents(), "cmy") == 0)
    col = read_cmy();
  else {
    warning(WARN_COLOR,
            "unknown color space `%1'; use rgb, cmyk, gray or cmy",
            style.contents());
    skip_line();
    return;
  }
  if (col) {
    col->nm = color_name;
    (void)color_dictionary.lookup(color_name, col);
  }
  skip_line();
}

static node *do_overstrike()
{
  token start;
  overstrike_node *on = new overstrike_node;
  int start_level = input_stack::get_level();
  start.next();
  for (;;) {
    tok.next();
    if (tok.newline() || tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    charinfo *ci = tok.get_char(1);
    if (ci) {
      node *n = curenv->make_char_node(ci);
      if (n)
        on->overstrike(n);
    }
  }
  return on;
}

static node *do_bracket()
{
  token start;
  bracket_node *bn = new bracket_node;
  start.next();
  int start_level = input_stack::get_level();
  for (;;) {
    tok.next();
    if (tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      break;
    }
    if (tok.newline()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    charinfo *ci = tok.get_char(1);
    if (ci) {
      node *n = curenv->make_char_node(ci);
      if (n)
        bn->bracket(n);
    }
  }
  return bn;
}

static int do_name_test()
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  int bad_char = 0;
  int some_char = 0;
  for (;;) {
    tok.next();
    if (tok.newline() || tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    if (!tok.ch())
      bad_char = 1;
    some_char = 1;
  }
  return some_char && !bad_char;
}

static int do_expr_test()
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  if (!start.delimiter(1))
    return 0;
  tok.next();
  // disable all warning and error messages temporarily
  int saved_warning_mask = warning_mask;
  int saved_inhibit_errors = inhibit_errors;
  warning_mask = 0;
  inhibit_errors = 1;
  int dummy;
  int result = get_number_rigidly(&dummy, 'u');
  warning_mask = saved_warning_mask;
  inhibit_errors = saved_inhibit_errors;
  if (tok == start && input_stack::get_level() == start_level)
    return result;
  // ignore everything up to the delimiter in case we aren't right there
  for (;;) {
    tok.next();
    if (tok.newline() || tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start && input_stack::get_level() == start_level)
      break;
  }
  return 0;
}

#if 0
static node *do_zero_width()
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  environment env(curenv);
  environment *oldenv = curenv;
  curenv = &env;
  for (;;) {
    tok.next();
    if (tok.newline() || tok.eof()) {
      error("missing closing delimiter");
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    tok.process();
  }
  curenv = oldenv;
  node *rev = env.extract_output_line();
  node *n = 0;
  while (rev) {
    node *tem = rev;
    rev = rev->next;
    tem->next = n;
    n = tem;
  }
  return new zero_width_node(n);
}

#else

// It's undesirable for \Z to change environments, because then
// \n(.w won't work as expected.

static node *do_zero_width()
{
  node *rev = new dummy_node;
  token start;
  start.next();
  int start_level = input_stack::get_level();
  for (;;) {
    tok.next();
    if (tok.newline() || tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    if (!tok.add_to_node_list(&rev))
      error("invalid token in argument to \\Z");
  }
  node *n = 0;
  while (rev) {
    node *tem = rev;
    rev = rev->next;
    tem->next = n;
    n = tem;
  }
  return new zero_width_node(n);
}

#endif

token_node *node::get_token_node()
{
  return 0;
}

class token_node : public node {
public:
  token tk;
  token_node(const token &t);
  node *copy();
  token_node *get_token_node();
  int same(node *);
  const char *type();
  int force_tprint();
  int is_tag();
};

token_node::token_node(const token &t) : tk(t)
{
}

node *token_node::copy()
{
  return new token_node(tk);
}

token_node *token_node::get_token_node()
{
  return this;
}

int token_node::same(node *nd)
{
  return tk == ((token_node *)nd)->tk;
}

const char *token_node::type()
{
  return "token_node";
}

int token_node::force_tprint()
{
  return 0;
}

int token_node::is_tag()
{
  return 0;
}

token::token() : nd(0), type(TOKEN_EMPTY)
{
}

token::~token()
{
  delete nd;
}

token::token(const token &t)
: nm(t.nm), c(t.c), val(t.val), dim(t.dim), type(t.type)
{
  // Use two statements to work around bug in SGI C++.
  node *tem = t.nd;
  nd = tem ? tem->copy() : 0;
}

void token::operator=(const token &t)
{
  delete nd;
  nm = t.nm;
  // Use two statements to work around bug in SGI C++.
  node *tem = t.nd;
  nd = tem ? tem->copy() : 0;
  c = t.c;
  val = t.val;
  dim = t.dim;
  type = t.type;
}

void token::skip()
{
  while (space())
    next();
}

int has_arg()
{
  while (tok.space())
    tok.next();
  return !tok.newline();
}

void token::make_space()
{
  type = TOKEN_SPACE;
}

void token::make_newline()
{
  type = TOKEN_NEWLINE;
}

void token::next()
{
  if (nd) {
    delete nd;
    nd = 0;
  }
  units x;
  for (;;) {
    node *n = 0;
    int cc = input_stack::get(&n);
    if (cc != escape_char || escape_char == 0) {
    handle_normal_char:
      switch(cc) {
      case PUSH_GROFF_MODE:
        input_stack::save_compatible_flag(compatible_flag);
        compatible_flag = 0;
        continue;
      case PUSH_COMP_MODE:
        input_stack::save_compatible_flag(compatible_flag);
        compatible_flag = 1;
        continue;
      case POP_GROFFCOMP_MODE:
        compatible_flag = input_stack::get_compatible_flag();
        continue;
      case BEGIN_QUOTE:
        input_stack::increase_level();
        continue;
      case END_QUOTE:
        input_stack::decrease_level();
        continue;
      case DOUBLE_QUOTE:
        continue;
      case EOF:
        type = TOKEN_EOF;
        return;
      case TRANSPARENT_FILE_REQUEST:
      case TITLE_REQUEST:
      case COPY_FILE_REQUEST:
#ifdef COLUMN
      case VJUSTIFY_REQUEST:
#endif /* COLUMN */
        type = TOKEN_REQUEST;
        c = cc;
        return;
      case BEGIN_TRAP:
        type = TOKEN_BEGIN_TRAP;
        return;
      case END_TRAP:
        type = TOKEN_END_TRAP;
        return;
      case LAST_PAGE_EJECTOR:
        seen_last_page_ejector = 1;
        // fall through
      case PAGE_EJECTOR:
        type = TOKEN_PAGE_EJECTOR;
        return;
      case ESCAPE_PERCENT:
      ESCAPE_PERCENT:
        type = TOKEN_HYPHEN_INDICATOR;
        return;
      case ESCAPE_SPACE:
      ESCAPE_SPACE:
        type = TOKEN_UNSTRETCHABLE_SPACE;
        return;
      case ESCAPE_TILDE:
      ESCAPE_TILDE:
        type = TOKEN_STRETCHABLE_SPACE;
        return;
      case ESCAPE_COLON:
      ESCAPE_COLON:
        type = TOKEN_ZERO_WIDTH_BREAK;
        return;
      case ESCAPE_e:
      ESCAPE_e:
        type = TOKEN_ESCAPE;
        return;
      case ESCAPE_E:
        goto handle_escape_char;
      case ESCAPE_BAR:
      ESCAPE_BAR:
        type = TOKEN_NODE;
        nd = new hmotion_node(curenv->get_narrow_space_width(),
                              curenv->get_fill_color());
        return;
      case ESCAPE_CIRCUMFLEX:
      ESCAPE_CIRCUMFLEX:
        type = TOKEN_NODE;
        nd = new hmotion_node(curenv->get_half_narrow_space_width(),
                              curenv->get_fill_color());
        return;
      case ESCAPE_NEWLINE:
        have_input = 0;
        break;
      case ESCAPE_LEFT_BRACE:
      ESCAPE_LEFT_BRACE:
        type = TOKEN_LEFT_BRACE;
        return;
      case ESCAPE_RIGHT_BRACE:
      ESCAPE_RIGHT_BRACE:
        type = TOKEN_RIGHT_BRACE;
        return;
      case ESCAPE_LEFT_QUOTE:
      ESCAPE_LEFT_QUOTE:
        type = TOKEN_SPECIAL;
        nm = symbol("ga");
        return;
      case ESCAPE_RIGHT_QUOTE:
      ESCAPE_RIGHT_QUOTE:
        type = TOKEN_SPECIAL;
        nm = symbol("aa");
        return;
      case ESCAPE_HYPHEN:
      ESCAPE_HYPHEN:
        type = TOKEN_SPECIAL;
        nm = symbol("-");
        return;
      case ESCAPE_UNDERSCORE:
      ESCAPE_UNDERSCORE:
        type = TOKEN_SPECIAL;
        nm = symbol("ul");
        return;
      case ESCAPE_c:
      ESCAPE_c:
        type = TOKEN_INTERRUPT;
        return;
      case ESCAPE_BANG:
      ESCAPE_BANG:
        type = TOKEN_TRANSPARENT;
        return;
      case ESCAPE_QUESTION:
      ESCAPE_QUESTION:
        nd = do_non_interpreted();
        if (nd) {
          type = TOKEN_NODE;
          return;
        }
        break;
      case ESCAPE_AMPERSAND:
      ESCAPE_AMPERSAND:
        type = TOKEN_DUMMY;
        return;
      case ESCAPE_RIGHT_PARENTHESIS:
      ESCAPE_RIGHT_PARENTHESIS:
        type = TOKEN_TRANSPARENT_DUMMY;
        return;
      case '\b':
        type = TOKEN_BACKSPACE;
        return;
      case ' ':
        type = TOKEN_SPACE;
        return;
      case '\t':
        type = TOKEN_TAB;
        return;
      case '\n':
        type = TOKEN_NEWLINE;
        return;
      case '\001':
        type = TOKEN_LEADER;
        return;
      case 0:
        {
          assert(n != 0);
          token_node *tn = n->get_token_node();
          if (tn) {
            *this = tn->tk;
            delete tn;
          }
          else {
            nd = n;
            type = TOKEN_NODE;
          }
        }
        return;
      default:
        type = TOKEN_CHAR;
        c = cc;
        return;
      }
    }
    else {
    handle_escape_char:
      cc = input_stack::get(&n);
      switch(cc) {
      case '(':
        nm = read_two_char_escape_name();
        type = TOKEN_SPECIAL;
        return;
      case EOF:
        type = TOKEN_EOF;
        error("end of input after escape character");
        return;
      case '`':
        goto ESCAPE_LEFT_QUOTE;
      case '\'':
        goto ESCAPE_RIGHT_QUOTE;
      case '-':
        goto ESCAPE_HYPHEN;
      case '_':
        goto ESCAPE_UNDERSCORE;
      case '%':
        goto ESCAPE_PERCENT;
      case ' ':
        goto ESCAPE_SPACE;
      case '0':
        nd = new hmotion_node(curenv->get_digit_width(),
                              curenv->get_fill_color());
        type = TOKEN_NODE;
        return;
      case '|':
        goto ESCAPE_BAR;
      case '^':
        goto ESCAPE_CIRCUMFLEX;
      case '/':
        type = TOKEN_ITALIC_CORRECTION;
        return;
      case ',':
        type = TOKEN_NODE;
        nd = new left_italic_corrected_node;
        return;
      case '&':
        goto ESCAPE_AMPERSAND;
      case ')':
        goto ESCAPE_RIGHT_PARENTHESIS;
      case '!':
        goto ESCAPE_BANG;
      case '?':
        goto ESCAPE_QUESTION;
      case '~':
        goto ESCAPE_TILDE;
      case ':':
        goto ESCAPE_COLON;
      case '"':
        while ((cc = input_stack::get(0)) != '\n' && cc != EOF)
          ;
        if (cc == '\n')
          type = TOKEN_NEWLINE;
        else
          type = TOKEN_EOF;
        return;
      case '#':                 // Like \" but newline is ignored.
        while ((cc = input_stack::get(0)) != '\n')
          if (cc == EOF) {
            type = TOKEN_EOF;
            return;
          }
        break;
      case '$':
        {
          symbol s = read_escape_name();
          if (!(s.is_null() || s.is_empty()))
            interpolate_arg(s);
          break;
        }
      case '*':
        {
          symbol s = read_escape_name(WITH_ARGS);
          if (!(s.is_null() || s.is_empty())) {
            if (have_string_arg) {
              have_string_arg = 0;
              interpolate_string_with_args(s);
            }
            else
              interpolate_string(s);
          }
          break;
        }
      case 'a':
        nd = new non_interpreted_char_node('\001');
        type = TOKEN_NODE;
        return;
      case 'A':
        c = '0' + do_name_test();
        type = TOKEN_CHAR;
        return;
      case 'b':
        nd = do_bracket();
        type = TOKEN_NODE;
        return;
      case 'B':
        c = '0' + do_expr_test();
        type = TOKEN_CHAR;
        return;
      case 'c':
        goto ESCAPE_c;
      case 'C':
        nm = get_delim_name();
        if (nm.is_null())
          break;
        type = TOKEN_SPECIAL;
        return;
      case 'd':
        type = TOKEN_NODE;
        nd = new vmotion_node(curenv->get_size() / 2,
                              curenv->get_fill_color());
        return;
      case 'D':
        nd = read_draw_node();
        if (!nd)
          break;
        type = TOKEN_NODE;
        return;
      case 'e':
        goto ESCAPE_e;
      case 'E':
        goto handle_escape_char;
      case 'f':
        {
          symbol s = read_escape_name(ALLOW_EMPTY);
          if (s.is_null())
            break;
          const char *p;
          for (p = s.contents(); *p != '\0'; p++)
            if (!csdigit(*p))
              break;
          if (*p || s.is_empty())
            curenv->set_font(s);
          else
            curenv->set_font(atoi(s.contents()));
          if (!compatible_flag)
            have_input = 1;
          break;
        }
      case 'F':
        {
          symbol s = read_escape_name(ALLOW_EMPTY);
          if (s.is_null())
            break;
          curenv->set_family(s);
          have_input = 1;
          break;
        }
      case 'g':
        {
          symbol s = read_escape_name();
          if (!(s.is_null() || s.is_empty()))
            interpolate_number_format(s);
          break;
        }
      case 'h':
        if (!get_delim_number(&x, 'm'))
          break;
        type = TOKEN_NODE;
        nd = new hmotion_node(x, curenv->get_fill_color());
        return;
      case 'H':
        // don't take height increments relative to previous height if
        // in compatibility mode
        if (!compatible_flag && curenv->get_char_height()) {
          if (get_delim_number(&x, 'z', curenv->get_char_height()))
            curenv->set_char_height(x);
        }
        else {
          if (get_delim_number(&x, 'z', curenv->get_requested_point_size()))
            curenv->set_char_height(x);
        }
        if (!compatible_flag)
          have_input = 1;
        break;
      case 'k':
        nm = read_escape_name();
        if (nm.is_null() || nm.is_empty())
          break;
        type = TOKEN_MARK_INPUT;
        return;
      case 'l':
      case 'L':
        {
          charinfo *s = 0;
          if (!get_line_arg(&x, (cc == 'l' ? 'm': 'v'), &s))
            break;
          if (s == 0)
            s = get_charinfo(cc == 'l' ? "ru" : "br");
          type = TOKEN_NODE;
          node *char_node = curenv->make_char_node(s);
          if (cc == 'l')
            nd = new hline_node(x, char_node);
          else
            nd = new vline_node(x, char_node);
          return;
        }
      case 'm':
        do_glyph_color(read_escape_name(ALLOW_EMPTY));
        if (!compatible_flag)
          have_input = 1;
        break;
      case 'M':
        do_fill_color(read_escape_name(ALLOW_EMPTY));
        if (!compatible_flag)
          have_input = 1;
        break;
      case 'n':
        {
          int inc;
          symbol s = read_increment_and_escape_name(&inc);
          if (!(s.is_null() || s.is_empty()))
            interpolate_number_reg(s, inc);
          break;
        }
      case 'N':
        if (!get_delim_number(&val, 0))
          break;
        if (val < 0) {
          warning(WARN_CHAR, "invalid numbered character %1", val);
          break;
        }
        type = TOKEN_NUMBERED_CHAR;
        return;
      case 'o':
        nd = do_overstrike();
        type = TOKEN_NODE;
        return;
      case 'O':
        nd = do_suppress(read_escape_name());
        if (!nd)
          break;
        type = TOKEN_NODE;
        return;
      case 'p':
        type = TOKEN_SPREAD;
        return;
      case 'r':
        type = TOKEN_NODE;
        nd = new vmotion_node(-curenv->get_size(), curenv->get_fill_color());
        return;
      case 'R':
        do_register();
        if (!compatible_flag)
          have_input = 1;
        break;
      case 's':
        if (read_size(&x))
          curenv->set_size(x);
        if (!compatible_flag)
          have_input = 1;
        break;
      case 'S':
        if (get_delim_number(&x, 0))
          curenv->set_char_slant(x);
        if (!compatible_flag)
          have_input = 1;
        break;
      case 't':
        type = TOKEN_NODE;
        nd = new non_interpreted_char_node('\t');
        return;
      case 'u':
        type = TOKEN_NODE;
        nd = new vmotion_node(-curenv->get_size() / 2,
                              curenv->get_fill_color());
        return;
      case 'v':
        if (!get_delim_number(&x, 'v'))
          break;
        type = TOKEN_NODE;
        nd = new vmotion_node(x, curenv->get_fill_color());
        return;
      case 'V':
        {
          symbol s = read_escape_name();
          if (!(s.is_null() || s.is_empty()))
            interpolate_environment_variable(s);
          break;
        }
      case 'w':
        do_width();
        break;
      case 'x':
        if (!get_delim_number(&x, 'v'))
          break;
        type = TOKEN_NODE;
        nd = new extra_size_node(x);
        return;
      case 'X':
        nd = do_special();
        if (!nd)
          break;
        type = TOKEN_NODE;
        return;
      case 'Y':
        {
          symbol s = read_escape_name();
          if (s.is_null() || s.is_empty())
            break;
          request_or_macro *p = lookup_request(s);
          macro *m = p->to_macro();
          if (!m) {
            error("can't transparently throughput a request");
            break;
          }
          nd = new special_node(*m);
          type = TOKEN_NODE;
          return;
        }
      case 'z':
        {
          next();
          if (type == TOKEN_NODE)
            nd = new zero_width_node(nd);
          else {
            charinfo *ci = get_char(1);
            if (ci == 0)
              break;
            node *gn = curenv->make_char_node(ci);
            if (gn == 0)
              break;
            nd = new zero_width_node(gn);
            type = TOKEN_NODE;
          }
          return;
        }
      case 'Z':
        nd = do_zero_width();
        if (nd == 0)
          break;
        type = TOKEN_NODE;
        return;
      case '{':
        goto ESCAPE_LEFT_BRACE;
      case '}':
        goto ESCAPE_RIGHT_BRACE;
      case '\n':
        break;
      case '[':
        if (!compatible_flag) {
          symbol s = read_long_escape_name(WITH_ARGS);
          if (s.is_null() || s.is_empty())
            break;
          if (have_string_arg) {
            have_string_arg = 0;
            nm = composite_glyph_name(s);
          }
          else {
            const char *gn = check_unicode_name(s.contents());
            if (gn) {
              const char *gn_decomposed = decompose_unicode(gn);
              if (gn_decomposed)
                gn = &gn_decomposed[1];
              const char *groff_gn = unicode_to_glyph_name(gn);
              if (groff_gn)
                nm = symbol(groff_gn);
              else {
                char *buf = new char[strlen(gn) + 1 + 1];
                strcpy(buf, "u");
                strcat(buf, gn);
                nm = symbol(buf);
                a_delete buf;
              }
            }
            else
              nm = symbol(s.contents());
          }
          type = TOKEN_SPECIAL;
          return;
        }
        goto handle_normal_char;
      default:
        if (cc != escape_char && cc != '.')
          warning(WARN_ESCAPE, "escape character ignored before %1",
                  input_char_description(cc));
        goto handle_normal_char;
      }
    }
  }
}

int token::operator==(const token &t)
{
  if (type != t.type)
    return 0;
  switch(type) {
  case TOKEN_CHAR:
    return c == t.c;
  case TOKEN_SPECIAL:
    return nm == t.nm;
  case TOKEN_NUMBERED_CHAR:
    return val == t.val;
  default:
    return 1;
  }
}

int token::operator!=(const token &t)
{
  return !(*this == t);
}

// is token a suitable delimiter (like ')?

int token::delimiter(int err)
{
  switch(type) {
  case TOKEN_CHAR:
    switch(c) {
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
    case '+':
    case '-':
    case '/':
    case '*':
    case '%':
    case '<':
    case '>':
    case '=':
    case '&':
    case ':':
    case '(':
    case ')':
    case '.':
      if (err)
        error("cannot use character `%1' as a starting delimiter", char(c));
      return 0;
    default:
      return 1;
    }
  case TOKEN_NODE:
  case TOKEN_SPACE:
  case TOKEN_STRETCHABLE_SPACE:
  case TOKEN_UNSTRETCHABLE_SPACE:
  case TOKEN_TAB:
  case TOKEN_NEWLINE:
    if (err)
      error("cannot use %1 as a starting delimiter", description());
    return 0;
  default:
    return 1;
  }
}

const char *token::description()
{
  static char buf[4];
  switch (type) {
  case TOKEN_BACKSPACE:
    return "a backspace character";
  case TOKEN_CHAR:
    buf[0] = '`';
    buf[1] = c;
    buf[2] = '\'';
    buf[3] = '\0';
    return buf;
  case TOKEN_DUMMY:
    return "`\\&'";
  case TOKEN_ESCAPE:
    return "`\\e'";
  case TOKEN_HYPHEN_INDICATOR:
    return "`\\%'";
  case TOKEN_INTERRUPT:
    return "`\\c'";
  case TOKEN_ITALIC_CORRECTION:
    return "`\\/'";
  case TOKEN_LEADER:
    return "a leader character";
  case TOKEN_LEFT_BRACE:
    return "`\\{'";
  case TOKEN_MARK_INPUT:
    return "`\\k'";
  case TOKEN_NEWLINE:
    return "newline";
  case TOKEN_NODE:
    return "a node";
  case TOKEN_NUMBERED_CHAR:
    return "`\\N'";
  case TOKEN_RIGHT_BRACE:
    return "`\\}'";
  case TOKEN_SPACE:
    return "a space";
  case TOKEN_SPECIAL:
    return "a special character";
  case TOKEN_SPREAD:
    return "`\\p'";
  case TOKEN_STRETCHABLE_SPACE:
    return "`\\~'";
  case TOKEN_UNSTRETCHABLE_SPACE:
    return "`\\ '";
  case TOKEN_TAB:
    return "a tab character";
  case TOKEN_TRANSPARENT:
    return "`\\!'";
  case TOKEN_TRANSPARENT_DUMMY:
    return "`\\)'";
  case TOKEN_ZERO_WIDTH_BREAK:
    return "`\\:'";
  case TOKEN_EOF:
    return "end of input";
  default:
    break;
  }
  return "a magic token";
}

void skip_line()
{
  while (!tok.newline())
    if (tok.eof())
      return;
    else
      tok.next();
  tok.next();
}

void compatible()
{
  int n;
  if (has_arg() && get_integer(&n))
    compatible_flag = n != 0;
  else
    compatible_flag = 1;
  skip_line();
}

static void empty_name_warning(int required)
{
  if (tok.newline() || tok.eof()) {
    if (required)
      warning(WARN_MISSING, "missing name");
  }
  else if (tok.right_brace() || tok.tab()) {
    const char *start = tok.description();
    do {
      tok.next();
    } while (tok.space() || tok.right_brace() || tok.tab());
    if (!tok.newline() && !tok.eof())
      error("%1 is not allowed before an argument", start);
    else if (required)
      warning(WARN_MISSING, "missing name");
  }
  else if (required)
    error("name expected (got %1)", tok.description());
  else
    error("name expected (got %1): treated as missing", tok.description());
}

static void non_empty_name_warning()
{
  if (!tok.newline() && !tok.eof() && !tok.space() && !tok.tab()
      && !tok.right_brace()
      // We don't want to give a warning for .el\{
      && !tok.left_brace())
    error("%1 is not allowed in a name", tok.description());
}

symbol get_name(int required)
{
  if (compatible_flag) {
    char buf[3];
    tok.skip();
    if ((buf[0] = tok.ch()) != 0) {
      tok.next();
      if ((buf[1] = tok.ch()) != 0) {
        buf[2] = 0;
        tok.make_space();
      }
      else
        non_empty_name_warning();
      return symbol(buf);
    }
    else {
      empty_name_warning(required);
      return NULL_SYMBOL;
    }
  }
  else
    return get_long_name(required);
}

symbol get_long_name(int required)
{
  return do_get_long_name(required, 0);
}

static symbol do_get_long_name(int required, char end)
{
  while (tok.space())
    tok.next();
  char abuf[ABUF_SIZE];
  char *buf = abuf;
  int buf_size = ABUF_SIZE;
  int i = 0;
  for (;;) {
    // If end != 0 we normally have to append a null byte
    if (i + 2 > buf_size) {
      if (buf == abuf) {
        buf = new char[ABUF_SIZE*2];
        memcpy(buf, abuf, buf_size);
        buf_size = ABUF_SIZE*2;
      }
      else {
        char *old_buf = buf;
        buf = new char[buf_size*2];
        memcpy(buf, old_buf, buf_size);
        buf_size *= 2;
        a_delete old_buf;
      }
    }
    if ((buf[i] = tok.ch()) == 0 || buf[i] == end)
      break;
    i++;
    tok.next();
  }
  if (i == 0) {
    empty_name_warning(required);
    return NULL_SYMBOL;
  }
  if (end && buf[i] == end)
    buf[i+1] = '\0';
  else
    non_empty_name_warning();
  if (buf == abuf)
    return symbol(buf);
  else {
    symbol s(buf);
    a_delete buf;
    return s;
  }
}

void exit_troff()
{
  exit_started = 1;
  topdiv->set_last_page();
  if (!end_macro_name.is_null()) {
    spring_trap(end_macro_name);
    tok.next();
    process_input_stack();
  }
  curenv->final_break();
  tok.next();
  process_input_stack();
  end_diversions();
  if (topdiv->get_page_length() > 0) {
    done_end_macro = 1;
    topdiv->set_ejecting();
    static unsigned char buf[2] = { LAST_PAGE_EJECTOR, '\0' };
    input_stack::push(make_temp_iterator((char *)buf));
    topdiv->space(topdiv->get_page_length(), 1);
    tok.next();
    process_input_stack();
    seen_last_page_ejector = 1; // should be set already
    topdiv->set_ejecting();
    push_page_ejector();
    topdiv->space(topdiv->get_page_length(), 1);
    tok.next();
    process_input_stack();
  }
  // This will only happen if a trap-invoked macro starts a diversion,
  // or if vertical position traps have been disabled.
  cleanup_and_exit(0);
}

// This implements .ex.  The input stack must be cleared before calling
// exit_troff().

void exit_request()
{
  input_stack::clear();
  if (exit_started)
    tok.next();
  else
    exit_troff();
}

void return_macro_request()
{
  if (has_arg() && tok.ch())
    input_stack::pop_macro();
  input_stack::pop_macro();
  tok.next();
}

void end_macro()
{
  end_macro_name = get_name();
  skip_line();
}

void blank_line_macro()
{
  blank_line_macro_name = get_name();
  skip_line();
}

static void trapping_blank_line()
{
  if (!blank_line_macro_name.is_null())
    spring_trap(blank_line_macro_name);
  else
    blank_line();
}

void do_request()
{
  int old_compatible_flag = compatible_flag;
  compatible_flag = 0;
  symbol nm = get_name();
  if (nm.is_null())
    skip_line();
  else
    interpolate_macro(nm, 1);
  compatible_flag = old_compatible_flag;
  request_or_macro *p = lookup_request(nm);
  macro *m = p->to_macro();
  if (m)
    tok.next();
}

inline int possibly_handle_first_page_transition()
{
  if (topdiv->before_first_page && curdiv == topdiv && !curenv->is_dummy()) {
    handle_first_page_transition();
    return 1;
  }
  else
    return 0;
}

static int transparent_translate(int cc)
{
  if (!invalid_input_char(cc)) {
    charinfo *ci = charset_table[cc];
    switch (ci->get_special_translation(1)) {
    case charinfo::TRANSLATE_SPACE:
      return ' ';
    case charinfo::TRANSLATE_STRETCHABLE_SPACE:
      return ESCAPE_TILDE;
    case charinfo::TRANSLATE_DUMMY:
      return ESCAPE_AMPERSAND;
    case charinfo::TRANSLATE_HYPHEN_INDICATOR:
      return ESCAPE_PERCENT;
    }
    // This is really ugly.
    ci = ci->get_translation(1);
    if (ci) {
      int c = ci->get_ascii_code();
      if (c != '\0')
        return c;
      error("can't translate %1 to special character `%2'"
            " in transparent throughput",
            input_char_description(cc),
            ci->nm.contents());
    }
  }
  return cc;
}

class int_stack {
  struct int_stack_element {
    int n;
    int_stack_element *next;
  } *top;
public:
  int_stack();
  ~int_stack();
  void push(int);
  int is_empty();
  int pop();
};

int_stack::int_stack()
{
  top = 0;
}

int_stack::~int_stack()
{
  while (top != 0) {
    int_stack_element *temp = top;
    top = top->next;
    delete temp;
  }
}

int int_stack::is_empty()
{
  return top == 0;
}

void int_stack::push(int n)
{
  int_stack_element *p = new int_stack_element;
  p->next = top;
  p->n = n;
  top = p;
}

int int_stack::pop()
{
  assert(top != 0);
  int_stack_element *p = top;
  top = top->next;
  int n = p->n;
  delete p;
  return n;
}

int node::reread(int *)
{
  return 0;
}

int global_diverted_space = 0;

int diverted_space_node::reread(int *bolp)
{
  global_diverted_space = 1;
  if (curenv->get_fill())
    trapping_blank_line();
  else
    curdiv->space(n);
  global_diverted_space = 0;
  *bolp = 1;
  return 1;
}

int diverted_copy_file_node::reread(int *bolp)
{
  curdiv->copy_file(filename.contents());
  *bolp = 1;
  return 1;
}

int word_space_node::reread(int *)
{
  if (unformat) {
    for (width_list *w = orig_width; w; w = w->next)
      curenv->space(w->width, w->sentence_width);
    unformat = 0;
    return 1;
  }
  return 0;
}

int unbreakable_space_node::reread(int *)
{
  return 0;
}

int hmotion_node::reread(int *)
{
  if (unformat && was_tab) {
    curenv->handle_tab(0);
    unformat = 0;
    return 1;
  }
  return 0;
}

void process_input_stack()
{
  int_stack trap_bol_stack;
  int bol = 1;
  for (;;) {
    int suppress_next = 0;
    switch (tok.type) {
    case token::TOKEN_CHAR:
      {
        unsigned char ch = tok.c;
        if (bol && !have_input
            && (ch == curenv->control_char
                || ch == curenv->no_break_control_char)) {
          break_flag = ch == curenv->control_char;
          // skip tabs as well as spaces here
          do {
            tok.next();
          } while (tok.white_space());
          symbol nm = get_name();
#if defined(DEBUGGING)
          if (debug_state) {
            if (! nm.is_null()) {
              if (strcmp(nm.contents(), "test") == 0) {
                fprintf(stderr, "found it!\n");
                fflush(stderr);
              }
              fprintf(stderr, "interpreting [%s]", nm.contents());
              if (strcmp(nm.contents(), "di") == 0 && topdiv != curdiv)
                fprintf(stderr, " currently in diversion: %s",
                        curdiv->get_diversion_name());
              fprintf(stderr, "\n");
              fflush(stderr);
            }
          }
#endif
          if (nm.is_null())
            skip_line();
          else {
            interpolate_macro(nm);
#if defined(DEBUGGING)
            if (debug_state) {
              fprintf(stderr, "finished interpreting [%s] and environment state is\n", nm.contents());
              curenv->dump_troff_state();
            }
#endif
          }
          suppress_next = 1;
        }
        else {
          if (possibly_handle_first_page_transition())
            ;
          else {
            for (;;) {
#if defined(DEBUGGING)
              if (debug_state) {
                fprintf(stderr, "found [%c]\n", ch); fflush(stderr);
              }
#endif
              curenv->add_char(charset_table[ch]);
              tok.next();
              if (tok.type != token::TOKEN_CHAR)
                break;
              ch = tok.c;
            }
            suppress_next = 1;
            bol = 0;
          }
        }
        break;
      }
    case token::TOKEN_TRANSPARENT:
      {
        if (bol) {
          if (possibly_handle_first_page_transition())
            ;
          else {
            int cc;
            do {
              node *n;
              cc = get_copy(&n);
              if (cc != EOF) {
                if (cc != '\0')
                  curdiv->transparent_output(transparent_translate(cc));
                else
                  curdiv->transparent_output(n);
              }
            } while (cc != '\n' && cc != EOF);
            if (cc == EOF)
              curdiv->transparent_output('\n');
          }
        }
        break;
      }
    case token::TOKEN_NEWLINE:
      {
        if (bol && !old_have_input
            && !curenv->get_prev_line_interrupted())
          trapping_blank_line();
        else {
          curenv->newline();
          bol = 1;
        }
        break;
      }
    case token::TOKEN_REQUEST:
      {
        int request_code = tok.c;
        tok.next();
        switch (request_code) {
        case TITLE_REQUEST:
          title();
          break;
        case COPY_FILE_REQUEST:
          copy_file();
          break;
        case TRANSPARENT_FILE_REQUEST:
          transparent_file();
          break;
#ifdef COLUMN
        case VJUSTIFY_REQUEST:
          vjustify();
          break;
#endif /* COLUMN */
        default:
          assert(0);
          break;
        }
        suppress_next = 1;
        break;
      }
    case token::TOKEN_SPACE:
      {
        if (possibly_handle_first_page_transition())
          ;
        else if (bol && !curenv->get_prev_line_interrupted()) {
          int nspaces = 0;
          // save space_width now so that it isn't changed by \f or \s
          // which we wouldn't notice here
          hunits space_width = curenv->get_space_width();
          do {
            nspaces += tok.nspaces();
            tok.next();
          } while (tok.space());
          if (tok.newline())
            trapping_blank_line();
          else {
            push_token(tok);
            curenv->do_break();
            curenv->add_node(new hmotion_node(space_width * nspaces,
                                              curenv->get_fill_color()));
            bol = 0;
          }
        }
        else {
          curenv->space();
          bol = 0;
        }
        break;
      }
    case token::TOKEN_EOF:
      return;
    case token::TOKEN_NODE:
      {
        if (possibly_handle_first_page_transition())
          ;
        else if (tok.nd->reread(&bol)) {
          delete tok.nd;
          tok.nd = 0;
        }
        else {
          curenv->add_node(tok.nd);
          tok.nd = 0;
          bol = 0;
          curenv->possibly_break_line(1);
        }
        break;
      }
    case token::TOKEN_PAGE_EJECTOR:
      {
        continue_page_eject();
        // I think we just want to preserve bol.
        // bol = 1;
        break;
      }
    case token::TOKEN_BEGIN_TRAP:
      {
        trap_bol_stack.push(bol);
        bol = 1;
        have_input = 0;
        break;
      }
    case token::TOKEN_END_TRAP:
      {
        if (trap_bol_stack.is_empty())
          error("spurious end trap token detected!");
        else
          bol = trap_bol_stack.pop();
        have_input = 0;

        /* I'm not totally happy about this.  But I can't think of any other
          way to do it.  Doing an output_pending_lines() whenever a
          TOKEN_END_TRAP is detected doesn't work: for example,

          .wh -1i x
          .de x
          'bp
          ..
          .wh -.5i y
          .de y
          .tl ''-%-''
          ..
          .br
          .ll .5i
          .sp |\n(.pu-1i-.5v
          a\%very\%very\%long\%word

          will print all but the first lines from the word immediately
          after the footer, rather than on the next page. */

        if (trap_bol_stack.is_empty())
          curenv->output_pending_lines();
        break;
      }
    default:
      {
        bol = 0;
        tok.process();
        break;
      }
    }
    if (!suppress_next)
      tok.next();
    trap_sprung_flag = 0;
  }
}

#ifdef WIDOW_CONTROL

void flush_pending_lines()
{
  while (!tok.newline() && !tok.eof())
    tok.next();
  curenv->output_pending_lines();
  tok.next();
}

#endif /* WIDOW_CONTROL */

request_or_macro::request_or_macro()
{
}

macro *request_or_macro::to_macro()
{
  return 0;
}

request::request(REQUEST_FUNCP pp) : p(pp)
{
}

void request::invoke(symbol, int)
{
  (*p)();
}

struct char_block {
  enum { SIZE = 128 };
  unsigned char s[SIZE];
  char_block *next;
  char_block();
};

char_block::char_block()
: next(0)
{
}

class char_list {
public:
  char_list();
  ~char_list();
  void append(unsigned char);
  void set(unsigned char, int);
  unsigned char get(int);
  int length();
private:
  unsigned char *ptr;
  int len;
  char_block *head;
  char_block *tail;
  friend class macro_header;
  friend class string_iterator;
};

char_list::char_list()
: ptr(0), len(0), head(0), tail(0)
{
}

char_list::~char_list()
{
  while (head != 0) {
    char_block *tem = head;
    head = head->next;
    delete tem;
  }
}

int char_list::length()
{
  return len;
}

void char_list::append(unsigned char c)
{
  if (tail == 0) {
    head = tail = new char_block;
    ptr = tail->s;
  }
  else {
    if (ptr >= tail->s + char_block::SIZE) {
      tail->next = new char_block;
      tail = tail->next;
      ptr = tail->s;
    }
  }
  *ptr++ = c;
  len++;
}

void char_list::set(unsigned char c, int offset)
{
  assert(len > offset);
  // optimization for access at the end
  int boundary = len - len % char_block::SIZE;
  if (offset >= boundary) {
    *(tail->s + offset - boundary) = c;
    return;
  }
  char_block *tem = head;
  int l = 0;
  for (;;) {
    l += char_block::SIZE;
    if (l > offset) {
      *(tem->s + offset % char_block::SIZE) = c;
      return;
    }
    tem = tem->next;
  }
}

unsigned char char_list::get(int offset)
{
  assert(len > offset);
  // optimization for access at the end
  int boundary = len - len % char_block::SIZE;
  if (offset >= boundary)
    return *(tail->s + offset - boundary);
  char_block *tem = head;
  int l = 0;
  for (;;) {
    l += char_block::SIZE;
    if (l > offset)
      return *(tem->s + offset % char_block::SIZE);
    tem = tem->next;
  }
}

class node_list {
  node *head;
  node *tail;
public:
  node_list();
  ~node_list();
  void append(node *);
  int length();
  node *extract();

  friend class macro_header;
  friend class string_iterator;
};

void node_list::append(node *n)
{
  if (head == 0) {
    n->next = 0;
    head = tail = n;
  }
  else {
    n->next = 0;
    tail = tail->next = n;
  }
}

int node_list::length()
{
  int total = 0;
  for (node *n = head; n != 0; n = n->next)
    ++total;
  return total;
}

node_list::node_list()
{
  head = tail = 0;
}

node *node_list::extract()
{
  node *temp = head;
  head = tail = 0;
  return temp;
}

node_list::~node_list()
{
  delete_node_list(head);
}

class macro_header {
public:
  int count;
  char_list cl;
  node_list nl;
  macro_header() { count = 1; }
  macro_header *copy(int);
};

macro::~macro()
{
  if (p != 0 && --(p->count) <= 0)
    delete p;
}

macro::macro()
: is_a_diversion(0), is_a_string(1)
{
  if (!input_stack::get_location(1, &filename, &lineno)) {
    filename = 0;
    lineno = 0;
  }
  len = 0;
  empty_macro = 1;
  p = 0;
}

macro::macro(const macro &m)
: filename(m.filename), lineno(m.lineno), len(m.len),
  empty_macro(m.empty_macro), is_a_diversion(m.is_a_diversion),
  is_a_string(m.is_a_string), p(m.p)
{
  if (p != 0)
    p->count++;
}

macro::macro(int is_div)
: is_a_diversion(is_div)
{
  if (!input_stack::get_location(1, &filename, &lineno)) {
    filename = 0;
    lineno = 0;
  }
  len = 0;
  empty_macro = 1;
  is_a_string = 1;
  p = 0;
}

int macro::is_diversion()
{
  return is_a_diversion;
}

int macro::is_string()
{
  return is_a_string;
}

void macro::clear_string_flag()
{
  is_a_string = 0;
}

macro &macro::operator=(const macro &m)
{
  // don't assign object
  if (m.p != 0)
    m.p->count++;
  if (p != 0 && --(p->count) <= 0)
    delete p;
  p = m.p;
  filename = m.filename;
  lineno = m.lineno;
  len = m.len;
  empty_macro = m.empty_macro;
  is_a_diversion = m.is_a_diversion;
  is_a_string = m.is_a_string;
  return *this;
}

void macro::append(unsigned char c)
{
  assert(c != 0);
  if (p == 0)
    p = new macro_header;
  if (p->cl.length() != len) {
    macro_header *tem = p->copy(len);
    if (--(p->count) <= 0)
      delete p;
    p = tem;
  }
  p->cl.append(c);
  ++len;
  if (c != PUSH_GROFF_MODE && c != PUSH_COMP_MODE && c != POP_GROFFCOMP_MODE)
    empty_macro = 0;
}

void macro::set(unsigned char c, int offset)
{
  assert(p != 0);
  assert(c != 0);
  p->cl.set(c, offset);
}

unsigned char macro::get(int offset)
{
  assert(p != 0);
  return p->cl.get(offset);
}

int macro::length()
{
  return len;
}

void macro::append_str(const char *s)
{
  int i = 0;

  if (s) {
    while (s[i] != (char)0) {
      append(s[i]);
      i++;
    }
  }
}

void macro::append(node *n)
{
  assert(n != 0);
  if (p == 0)
    p = new macro_header;
  if (p->cl.length() != len) {
    macro_header *tem = p->copy(len);
    if (--(p->count) <= 0)
      delete p;
    p = tem;
  }
  p->cl.append(0);
  p->nl.append(n);
  ++len;
  empty_macro = 0;
}

void macro::append_unsigned(unsigned int i)
{
  unsigned int j = i / 10;
  if (j != 0)
    append_unsigned(j);
  append(((unsigned char)(((int)'0') + i % 10)));
}

void macro::append_int(int i)
{
  if (i < 0) {
    append('-');
    i = -i;
  }
  append_unsigned((unsigned int)i);
}

void macro::print_size()
{
  errprint("%1", len);
}

// make a copy of the first n bytes

macro_header *macro_header::copy(int n)
{
  macro_header *p = new macro_header;
  char_block *bp = cl.head;
  unsigned char *ptr = bp->s;
  node *nd = nl.head;
  while (--n >= 0) {
    if (ptr >= bp->s + char_block::SIZE) {
      bp = bp->next;
      ptr = bp->s;
    }
    unsigned char c = *ptr++;
    p->cl.append(c);
    if (c == 0) {
      p->nl.append(nd->copy());
      nd = nd->next;
    }
  }
  return p;
}

void print_macros()
{
  object_dictionary_iterator iter(request_dictionary);
  request_or_macro *rm;
  symbol s;
  while (iter.get(&s, (object **)&rm)) {
    assert(!s.is_null());
    macro *m = rm->to_macro();
    if (m) {
      errprint("%1\t", s.contents());
      m->print_size();
      errprint("\n");
    }
  }
  fflush(stderr);
  skip_line();
}

class string_iterator : public input_iterator {
  macro mac;
  const char *how_invoked;
  int newline_flag;
  int lineno;
  char_block *bp;
  int count;                    // of characters remaining
  node *nd;
  int saved_compatible_flag;
  int with_break;               // inherited from the caller
protected:
  symbol nm;
  string_iterator();
public:
  string_iterator(const macro &, const char * = 0, symbol = NULL_SYMBOL);
  int fill(node **);
  int peek();
  int get_location(int, const char **, int *);
  void backtrace();
  int get_break_flag() { return with_break; }
  void save_compatible_flag(int f) { saved_compatible_flag = f; }
  int get_compatible_flag() { return saved_compatible_flag; }
  int is_diversion();
};

string_iterator::string_iterator(const macro &m, const char *p, symbol s)
: input_iterator(m.is_a_diversion), mac(m), how_invoked(p), newline_flag(0),
  lineno(1), nm(s)
{
  count = mac.len;
  if (count != 0) {
    bp = mac.p->cl.head;
    nd = mac.p->nl.head;
    ptr = eptr = bp->s;
  }
  else {
    bp = 0;
    nd = 0;
    ptr = eptr = 0;
  }
  with_break = input_stack::get_break_flag();
}

string_iterator::string_iterator()
{
  bp = 0;
  nd = 0;
  ptr = eptr = 0;
  newline_flag = 0;
  how_invoked = 0;
  lineno = 1;
  count = 0;
  with_break = input_stack::get_break_flag();
}

int string_iterator::is_diversion()
{
  return mac.is_diversion();
}

int string_iterator::fill(node **np)
{
  if (newline_flag)
    lineno++;
  newline_flag = 0;
  if (count <= 0)
    return EOF;
  const unsigned char *p = eptr;
  if (p >= bp->s + char_block::SIZE) {
    bp = bp->next;
    p = bp->s;
  }
  if (*p == '\0') {
    if (np) {
      *np = nd->copy();
      if (is_diversion())
        (*np)->div_nest_level = input_stack::get_div_level();
      else
        (*np)->div_nest_level = 0;
    }
    nd = nd->next;
    eptr = ptr = p + 1;
    count--;
    return 0;
  }
  const unsigned char *e = bp->s + char_block::SIZE;
  if (e - p > count)
    e = p + count;
  ptr = p;
  while (p < e) {
    unsigned char c = *p;
    if (c == '\n' || c == ESCAPE_NEWLINE) {
      newline_flag = 1;
      p++;
      break;
    }
    if (c == '\0')
      break;
    p++;
  }
  eptr = p;
  count -= p - ptr;
  return *ptr++;
}

int string_iterator::peek()
{
  if (count <= 0)
    return EOF;
  const unsigned char *p = eptr;
  if (p >= bp->s + char_block::SIZE) {
    p = bp->next->s;
  }
  return *p;
}

int string_iterator::get_location(int allow_macro,
                                  const char **filep, int *linep)
{
  if (!allow_macro)
    return 0;
  if (mac.filename == 0)
    return 0;
  *filep = mac.filename;
  *linep = mac.lineno + lineno - 1;
  return 1;
}

void string_iterator::backtrace()
{
  if (mac.filename) {
    errprint("%1:%2: backtrace", mac.filename, mac.lineno + lineno - 1);
    if (how_invoked) {
      if (!nm.is_null())
        errprint(": %1 `%2'\n", how_invoked, nm.contents());
      else
        errprint(": %1\n", how_invoked);
    }
    else
      errprint("\n");
  }
}

class temp_iterator : public input_iterator {
  unsigned char *base;
  temp_iterator(const char *, int len);
public:
  ~temp_iterator();
  friend input_iterator *make_temp_iterator(const char *);
};

#ifdef __GNUG__
inline
#endif
temp_iterator::temp_iterator(const char *s, int len)
{
  base = new unsigned char[len];
  memcpy(base, s, len);
  ptr = base;
  eptr = base + len;
}

temp_iterator::~temp_iterator()
{
  a_delete base;
}

class small_temp_iterator : public input_iterator {
private:
  small_temp_iterator(const char *, int);
  ~small_temp_iterator();
  enum { BLOCK = 16 };
  static small_temp_iterator *free_list;
  void *operator new(size_t);
  void operator delete(void *);
  enum { SIZE = 12 };
  unsigned char buf[SIZE];
  friend input_iterator *make_temp_iterator(const char *);
};

small_temp_iterator *small_temp_iterator::free_list = 0;

void *small_temp_iterator::operator new(size_t n)
{
  assert(n == sizeof(small_temp_iterator));
  if (!free_list) {
    free_list =
      (small_temp_iterator *)new char[sizeof(small_temp_iterator)*BLOCK];
    for (int i = 0; i < BLOCK - 1; i++)
      free_list[i].next = free_list + i + 1;
    free_list[BLOCK-1].next = 0;
  }
  small_temp_iterator *p = free_list;
  free_list = (small_temp_iterator *)(free_list->next);
  p->next = 0;
  return p;
}

#ifdef __GNUG__
inline
#endif
void small_temp_iterator::operator delete(void *p)
{
  if (p) {
    ((small_temp_iterator *)p)->next = free_list;
    free_list = (small_temp_iterator *)p;
  }
}

small_temp_iterator::~small_temp_iterator()
{
}

#ifdef __GNUG__
inline
#endif
small_temp_iterator::small_temp_iterator(const char *s, int len)
{
  for (int i = 0; i < len; i++)
    buf[i] = s[i];
  ptr = buf;
  eptr = buf + len;
}

input_iterator *make_temp_iterator(const char *s)
{
  if (s == 0)
    return new small_temp_iterator(s, 0);
  else {
    int n = strlen(s);
    if (n <= small_temp_iterator::SIZE)
      return new small_temp_iterator(s, n);
    else
      return new temp_iterator(s, n);
  }
}

// this is used when macros with arguments are interpolated

struct arg_list {
  macro mac;
  int space_follows;
  arg_list *next;
  arg_list(const macro &, int);
  arg_list(const arg_list *);
  ~arg_list();
};

arg_list::arg_list(const macro &m, int s) : mac(m), space_follows(s), next(0)
{
}

arg_list::arg_list(const arg_list *al)
: next(0)
{
  mac = al->mac;
  space_follows = al->space_follows;
  arg_list **a = &next;
  arg_list *p = al->next;
  while (p) {
    *a = new arg_list(p->mac, p->space_follows);
    p = p->next;
    a = &(*a)->next;
  }
}

arg_list::~arg_list()
{
}

class macro_iterator : public string_iterator {
  arg_list *args;
  int argc;
  int with_break;               // whether called as .foo or 'foo
public:
  macro_iterator(symbol, macro &, const char * = "macro", int = 0);
  macro_iterator();
  ~macro_iterator();
  int has_args() { return 1; }
  input_iterator *get_arg(int);
  arg_list *get_arg_list();
  symbol get_macro_name();
  int space_follows_arg(int);
  int get_break_flag() { return with_break; }
  int nargs() { return argc; }
  void add_arg(const macro &, int);
  void shift(int);
  int is_macro() { return 1; }
  int is_diversion();
};

input_iterator *macro_iterator::get_arg(int i)
{
  if (i == 0)
    return make_temp_iterator(nm.contents());
  if (i > 0 && i <= argc) {
    arg_list *p = args;
    for (int j = 1; j < i; j++) {
      assert(p != 0);
      p = p->next;
    }
    return new string_iterator(p->mac);
  }
  else
    return 0;
}

arg_list *macro_iterator::get_arg_list()
{
  return args;
}

symbol macro_iterator::get_macro_name()
{
  return nm;
}

int macro_iterator::space_follows_arg(int i)
{
  if (i > 0 && i <= argc) {
    arg_list *p = args;
    for (int j = 1; j < i; j++) {
      assert(p != 0);
      p = p->next;
    }
    return p->space_follows;
  }
  else
    return 0;
}

void macro_iterator::add_arg(const macro &m, int s)
{
  arg_list **p;
  for (p = &args; *p; p = &((*p)->next))
    ;
  *p = new arg_list(m, s);
  ++argc;
}

void macro_iterator::shift(int n)
{
  while (n > 0 && argc > 0) {
    arg_list *tem = args;
    args = args->next;
    delete tem;
    --argc;
    --n;
  }
}

// This gets used by eg .if '\?xxx\?''.

int operator==(const macro &m1, const macro &m2)
{
  if (m1.len != m2.len)
    return 0;
  string_iterator iter1(m1);
  string_iterator iter2(m2);
  int n = m1.len;
  while (--n >= 0) {
    node *nd1 = 0;
    int c1 = iter1.get(&nd1);
    assert(c1 != EOF);
    node *nd2 = 0;
    int c2 = iter2.get(&nd2);
    assert(c2 != EOF);
    if (c1 != c2) {
      if (c1 == 0)
        delete nd1;
      else if (c2 == 0)
        delete nd2;
      return 0;
    }
    if (c1 == 0) {
      assert(nd1 != 0);
      assert(nd2 != 0);
      int are_same = nd1->type() == nd2->type() && nd1->same(nd2);
      delete nd1;
      delete nd2;
      if (!are_same)
        return 0;
    }
  }
  return 1;
}

static void interpolate_macro(symbol nm, int no_next)
{
  request_or_macro *p = (request_or_macro *)request_dictionary.lookup(nm);
  if (p == 0) {
    int warned = 0;
    const char *s = nm.contents();
    if (strlen(s) > 2) {
      request_or_macro *r;
      char buf[3];
      buf[0] = s[0];
      buf[1] = s[1];
      buf[2] = '\0';
      r = (request_or_macro *)request_dictionary.lookup(symbol(buf));
      if (r) {
        macro *m = r->to_macro();
        if (!m || !m->empty())
          warned = warning(WARN_SPACE,
                           "macro `%1' not defined "
                           "(possibly missing space after `%2')",
                           nm.contents(), buf);
      }
    }
    if (!warned) {
      warning(WARN_MAC, "macro `%1' not defined", nm.contents());
      p = new macro;
      request_dictionary.define(nm, p);
    }
  }
  if (p)
    p->invoke(nm, no_next);
  else {
    skip_line();
    return;
  }
}

static void decode_args(macro_iterator *mi)
{
  if (!tok.newline() && !tok.eof()) {
    node *n;
    int c = get_copy(&n);
    for (;;) {
      while (c == ' ')
        c = get_copy(&n);
      if (c == '\n' || c == EOF)
        break;
      macro arg;
      int quote_input_level = 0;
      int done_tab_warning = 0;
      arg.append(compatible_flag ? PUSH_COMP_MODE : PUSH_GROFF_MODE);
      // we store discarded double quotes for \$^
      if (c == '"') {
        arg.append(DOUBLE_QUOTE);
        quote_input_level = input_stack::get_level();
        c = get_copy(&n);
      }
      while (c != EOF && c != '\n' && !(c == ' ' && quote_input_level == 0)) {
        if (quote_input_level > 0 && c == '"'
            && (compatible_flag
                || input_stack::get_level() == quote_input_level)) {
          arg.append(DOUBLE_QUOTE);
          c = get_copy(&n);
          if (c == '"') {
            arg.append(c);
            c = get_copy(&n);
          }
          else
            break;
        }
        else {
          if (c == 0)
            arg.append(n);
          else {
            if (c == '\t' && quote_input_level == 0 && !done_tab_warning) {
              warning(WARN_TAB, "tab character in unquoted macro argument");
              done_tab_warning = 1;
            }
            arg.append(c);
          }
          c = get_copy(&n);
        }
      }
      arg.append(POP_GROFFCOMP_MODE);
      mi->add_arg(arg, (c == ' '));
    }
  }
}

static void decode_string_args(macro_iterator *mi)
{
  node *n;
  int c = get_copy(&n);
  for (;;) {
    while (c == ' ')
      c = get_copy(&n);
    if (c == '\n' || c == EOF) {
      error("missing `]'");
      break;
    }
    if (c == ']')
      break;
    macro arg;
    int quote_input_level = 0;
    int done_tab_warning = 0;
    if (c == '"') {
      quote_input_level = input_stack::get_level();
      c = get_copy(&n);
    }
    while (c != EOF && c != '\n'
           && !(c == ']' && quote_input_level == 0)
           && !(c == ' ' && quote_input_level == 0)) {
      if (quote_input_level > 0 && c == '"'
          && input_stack::get_level() == quote_input_level) {
        c = get_copy(&n);
        if (c == '"') {
          arg.append(c);
          c = get_copy(&n);
        }
        else
          break;
      }
      else {
        if (c == 0)
          arg.append(n);
        else {
          if (c == '\t' && quote_input_level == 0 && !done_tab_warning) {
            warning(WARN_TAB, "tab character in unquoted string argument");
            done_tab_warning = 1;
          }
          arg.append(c);
        }
        c = get_copy(&n);
      }
    }
    mi->add_arg(arg, (c == ' '));
  }
}

void macro::invoke(symbol nm, int no_next)
{
  macro_iterator *mi = new macro_iterator(nm, *this);
  decode_args(mi);
  input_stack::push(mi);
  // we must delay tok.next() in case the function has been called by
  // do_request to assure proper handling of compatible_flag
  if (!no_next)
    tok.next();
}

macro *macro::to_macro()
{
  return this;
}

int macro::empty()
{
  return empty_macro == 1;
}

macro_iterator::macro_iterator(symbol s, macro &m, const char *how_called,
                               int init_args)
: string_iterator(m, how_called, s), args(0), argc(0), with_break(break_flag)
{
  if (init_args) {
    arg_list *al = input_stack::get_arg_list();
    if (al) {
      args = new arg_list(al);
      argc = input_stack::nargs();
    }
  }
}

macro_iterator::macro_iterator() : args(0), argc(0), with_break(break_flag)
{
}

macro_iterator::~macro_iterator()
{
  while (args != 0) {
    arg_list *tem = args;
    args = args->next;
    delete tem;
  }
}

dictionary composite_dictionary(17);

void composite_request()
{
  symbol from = get_name(1);
  if (!from.is_null()) {
    const char *from_gn = glyph_name_to_unicode(from.contents());
    if (!from_gn) {
      from_gn = check_unicode_name(from.contents());
      if (!from_gn) {
        error("invalid composite glyph name `%1'", from.contents());
        skip_line();
        return;
      }
    }
    const char *from_decomposed = decompose_unicode(from_gn);
    if (from_decomposed)
      from_gn = &from_decomposed[1];
    symbol to = get_name(1);
    if (to.is_null())
      composite_dictionary.remove(symbol(from_gn));
    else {
      const char *to_gn = glyph_name_to_unicode(to.contents());
      if (!to_gn) {
        to_gn = check_unicode_name(to.contents());
        if (!to_gn) {
          error("invalid composite glyph name `%1'", to.contents());
          skip_line();
          return;
        }
      }
      const char *to_decomposed = decompose_unicode(to_gn);
      if (to_decomposed)
        to_gn = &to_decomposed[1];
      if (strcmp(from_gn, to_gn) == 0)
        composite_dictionary.remove(symbol(from_gn));
      else
        (void)composite_dictionary.lookup(symbol(from_gn), (void *)to_gn);
    }
  }
  skip_line();
}

static symbol composite_glyph_name(symbol nm)
{
  macro_iterator *mi = new macro_iterator();
  decode_string_args(mi);
  input_stack::push(mi);
  const char *gn = glyph_name_to_unicode(nm.contents());
  if (!gn) {
    gn = check_unicode_name(nm.contents());
    if (!gn) {
      error("invalid base glyph `%1' in composite glyph name", nm.contents());
      return EMPTY_SYMBOL;
    }
  }
  const char *gn_decomposed = decompose_unicode(gn);
  string glyph_name(gn_decomposed ? &gn_decomposed[1] : gn);
  string gl;
  int n = input_stack::nargs();
  for (int i = 1; i <= n; i++) {
    glyph_name += '_';
    input_iterator *p = input_stack::get_arg(i);
    gl.clear();
    int c;
    while ((c = p->get(0)) != EOF)
      if (c != DOUBLE_QUOTE)
        gl += c;
    gl += '\0';
    const char *u = glyph_name_to_unicode(gl.contents());
    if (!u) {
      u = check_unicode_name(gl.contents());
      if (!u) {
        error("invalid component `%1' in composite glyph name",
              gl.contents());
        return EMPTY_SYMBOL;
      }
    }
    const char *decomposed = decompose_unicode(u);
    if (decomposed)
      u = &decomposed[1];
    void *mapped_composite = composite_dictionary.lookup(symbol(u));
    if (mapped_composite)
      u = (const char *)mapped_composite;
    glyph_name += u;
  }
  glyph_name += '\0';
  const char *groff_gn = unicode_to_glyph_name(glyph_name.contents());
  if (groff_gn)
    return symbol(groff_gn);
  gl.clear();
  gl += 'u';
  gl += glyph_name;
  return symbol(gl.contents());
}

int trap_sprung_flag = 0;
int postpone_traps_flag = 0;
symbol postponed_trap;

void spring_trap(symbol nm)
{
  assert(!nm.is_null());
  trap_sprung_flag = 1;
  if (postpone_traps_flag) {
    postponed_trap = nm;
    return;
  }
  static char buf[2] = { BEGIN_TRAP, 0 };
  static char buf2[2] = { END_TRAP, '\0' };
  input_stack::push(make_temp_iterator(buf2));
  request_or_macro *p = lookup_request(nm);
  macro *m = p->to_macro();
  if (m)
    input_stack::push(new macro_iterator(nm, *m, "trap-invoked macro"));
  else
    error("you can't invoke a request with a trap");
  input_stack::push(make_temp_iterator(buf));
}

void postpone_traps()
{
  postpone_traps_flag = 1;
}

int unpostpone_traps()
{
  postpone_traps_flag = 0;
  if (!postponed_trap.is_null()) {
    spring_trap(postponed_trap);
    postponed_trap = NULL_SYMBOL;
    return 1;
  }
  else
    return 0;
}

void read_request()
{
  macro_iterator *mi = new macro_iterator;
  int reading_from_terminal = isatty(fileno(stdin));
  int had_prompt = 0;
  if (!tok.newline() && !tok.eof()) {
    int c = get_copy(0);
    while (c == ' ')
      c = get_copy(0);
    while (c != EOF && c != '\n' && c != ' ') {
      if (!invalid_input_char(c)) {
        if (reading_from_terminal)
          fputc(c, stderr);
        had_prompt = 1;
      }
      c = get_copy(0);
    }
    if (c == ' ') {
      tok.make_space();
      decode_args(mi);
    }
  }
  if (reading_from_terminal) {
    fputc(had_prompt ? ':' : '\a', stderr);
    fflush(stderr);
  }
  input_stack::push(mi);
  macro mac;
  int nl = 0;
  int c;
  while ((c = getchar()) != EOF) {
    if (invalid_input_char(c))
      warning(WARN_INPUT, "invalid input character code %1", int(c));
    else {
      if (c == '\n') {
        if (nl)
          break;
        else
          nl = 1;
      }
      else
        nl = 0;
      mac.append(c);
    }
  }
  if (reading_from_terminal)
    clearerr(stdin);
  input_stack::push(new string_iterator(mac));
  tok.next();
}

enum define_mode { DEFINE_NORMAL, DEFINE_APPEND, DEFINE_IGNORE };
enum calling_mode { CALLING_NORMAL, CALLING_INDIRECT };
enum comp_mode { COMP_IGNORE, COMP_DISABLE, COMP_ENABLE };

void do_define_string(define_mode mode, comp_mode comp)
{
  symbol nm;
  node *n = 0;          // pacify compiler
  int c;
  nm = get_name(1);
  if (nm.is_null()) {
    skip_line();
    return;
  }
  if (tok.newline())
    c = '\n';
  else if (tok.tab())
    c = '\t';
  else if (!tok.space()) {
    error("bad string definition");
    skip_line();
    return;
  }
  else
    c = get_copy(&n);
  while (c == ' ')
    c = get_copy(&n);
  if (c == '"')
    c = get_copy(&n);
  macro mac;
  request_or_macro *rm = (request_or_macro *)request_dictionary.lookup(nm);
  macro *mm = rm ? rm->to_macro() : 0;
  if (mode == DEFINE_APPEND && mm)
    mac = *mm;
  if (comp == COMP_DISABLE)
    mac.append(PUSH_GROFF_MODE);
  else if (comp == COMP_ENABLE)
    mac.append(PUSH_COMP_MODE);
  while (c != '\n' && c != EOF) {
    if (c == 0)
      mac.append(n);
    else
      mac.append((unsigned char)c);
    c = get_copy(&n);
  }
  if (comp == COMP_DISABLE || comp == COMP_ENABLE)
    mac.append(POP_GROFFCOMP_MODE);
  if (!mm) {
    mm = new macro;
    request_dictionary.define(nm, mm);
  }
  *mm = mac;
  tok.next();
}

void define_string()
{
  do_define_string(DEFINE_NORMAL,
                   compatible_flag ? COMP_ENABLE: COMP_IGNORE);
}

void define_nocomp_string()
{
  do_define_string(DEFINE_NORMAL, COMP_DISABLE);
}

void append_string()
{
  do_define_string(DEFINE_APPEND,
                   compatible_flag ? COMP_ENABLE : COMP_IGNORE);
}

void append_nocomp_string()
{
  do_define_string(DEFINE_APPEND, COMP_DISABLE);
}

void do_define_character(char_mode mode, const char *font_name)
{
  node *n = 0;          // pacify compiler
  int c;
  tok.skip();
  charinfo *ci = tok.get_char(1);
  if (ci == 0) {
    skip_line();
    return;
  }
  if (font_name) {
    string s(font_name);
    s += ' ';
    s += ci->nm.contents();
    s += '\0';
    ci = get_charinfo(symbol(s.contents()));
  }
  tok.next();
  if (tok.newline())
    c = '\n';
  else if (tok.tab())
    c = '\t';
  else if (!tok.space()) {
    error("bad character definition");
    skip_line();
    return;
  }
  else
    c = get_copy(&n);
  while (c == ' ' || c == '\t')
    c = get_copy(&n);
  if (c == '"')
    c = get_copy(&n);
  macro *m = new macro;
  while (c != '\n' && c != EOF) {
    if (c == 0)
      m->append(n);
    else
      m->append((unsigned char)c);
    c = get_copy(&n);
  }
  m = ci->setx_macro(m, mode);
  if (m)
    delete m;
  tok.next();
}

void define_character()
{
  do_define_character(CHAR_NORMAL);
}

void define_fallback_character()
{
  do_define_character(CHAR_FALLBACK);
}

void define_special_character()
{
  do_define_character(CHAR_SPECIAL);
}

static void remove_character()
{
  tok.skip();
  while (!tok.newline() && !tok.eof()) {
    if (!tok.space() && !tok.tab()) {
      charinfo *ci = tok.get_char(1);
      if (!ci)
        break;
      macro *m = ci->set_macro(0);
      if (m)
        delete m;
    }
    tok.next();
  }
  skip_line();
}

static void interpolate_string(symbol nm)
{
  request_or_macro *p = lookup_request(nm);
  macro *m = p->to_macro();
  if (!m)
    error("you can only invoke a string or macro using \\*");
  else {
    if (m->is_string()) {
      string_iterator *si = new string_iterator(*m, "string", nm);
      input_stack::push(si);
     }
    else {
      // if a macro is called as a string, \$0 doesn't get changed
      macro_iterator *mi = new macro_iterator(input_stack::get_macro_name(),
                                              *m, "string", 1);
      input_stack::push(mi);
    }
  }
}

static void interpolate_string_with_args(symbol s)
{
  request_or_macro *p = lookup_request(s);
  macro *m = p->to_macro();
  if (!m)
    error("you can only invoke a string or macro using \\*");
  else {
    macro_iterator *mi = new macro_iterator(s, *m);
    decode_string_args(mi);
    input_stack::push(mi);
  }
}

static void interpolate_arg(symbol nm)
{
  const char *s = nm.contents();
  if (!s || *s == '\0')
    copy_mode_error("missing argument name");
  else if (s[1] == 0 && csdigit(s[0]))
    input_stack::push(input_stack::get_arg(s[0] - '0'));
  else if (s[0] == '*' && s[1] == '\0') {
    int limit = input_stack::nargs();
    string args;
    for (int i = 1; i <= limit; i++) {
      input_iterator *p = input_stack::get_arg(i);
      int c;
      while ((c = p->get(0)) != EOF)
        if (c != DOUBLE_QUOTE)
          args += c;
      if (i != limit)
        args += ' ';
    }
    if (limit > 0) {
      args += '\0';
      input_stack::push(make_temp_iterator(args.contents()));
    }
  }
  else if (s[0] == '@' && s[1] == '\0') {
    int limit = input_stack::nargs();
    string args;
    for (int i = 1; i <= limit; i++) {
      args += '"';
      args += char(BEGIN_QUOTE);
      input_iterator *p = input_stack::get_arg(i);
      int c;
      while ((c = p->get(0)) != EOF)
        if (c != DOUBLE_QUOTE)
          args += c;
      args += char(END_QUOTE);
      args += '"';
      if (i != limit)
        args += ' ';
    }
    if (limit > 0) {
      args += '\0';
      input_stack::push(make_temp_iterator(args.contents()));
    }
  }
  else if (s[0] == '^' && s[1] == '\0') {
    int limit = input_stack::nargs();
    string args;
    int c = input_stack::peek();
    for (int i = 1; i <= limit; i++) {
      input_iterator *p = input_stack::get_arg(i);
      while ((c = p->get(0)) != EOF) {
        if (c == DOUBLE_QUOTE)
          c = '"';
        args += c;
      }
      if (input_stack::space_follows_arg(i))
        args += ' ';
    }
    if (limit > 0) {
      args += '\0';
      input_stack::push(make_temp_iterator(args.contents()));
    }
  }
  else {
    const char *p;
    for (p = s; *p && csdigit(*p); p++)
      ;
    if (*p)
      copy_mode_error("bad argument name `%1'", s);
    else
      input_stack::push(input_stack::get_arg(atoi(s)));
  }
}

void handle_first_page_transition()
{
  push_token(tok);
  topdiv->begin_page();
}

// We push back a token by wrapping it up in a token_node, and
// wrapping that up in a string_iterator.

static void push_token(const token &t)
{
  macro m;
  m.append(new token_node(t));
  input_stack::push(new string_iterator(m));
}

void push_page_ejector()
{
  static char buf[2] = { PAGE_EJECTOR, '\0' };
  input_stack::push(make_temp_iterator(buf));
}

void handle_initial_request(unsigned char code)
{
  char buf[2];
  buf[0] = code;
  buf[1] = '\0';
  macro mac;
  mac.append(new token_node(tok));
  input_stack::push(new string_iterator(mac));
  input_stack::push(make_temp_iterator(buf));
  topdiv->begin_page();
  tok.next();
}

void handle_initial_title()
{
  handle_initial_request(TITLE_REQUEST);
}

// this should be local to define_macro, but cfront 1.2 doesn't support that
static symbol dot_symbol(".");

void do_define_macro(define_mode mode, calling_mode calling, comp_mode comp)
{
  symbol nm, term;
  if (calling == CALLING_INDIRECT) {
    symbol temp1 = get_name(1);
    if (temp1.is_null()) {
      skip_line();
      return;
    }
    symbol temp2 = get_name();
    input_stack::push(make_temp_iterator("\n"));
    if (!temp2.is_null()) {
      interpolate_string(temp2);
      input_stack::push(make_temp_iterator(" "));
    }
    interpolate_string(temp1);
    input_stack::push(make_temp_iterator(" "));
    tok.next();
  }
  if (mode == DEFINE_NORMAL || mode == DEFINE_APPEND) {
    nm = get_name(1);
    if (nm.is_null()) {
      skip_line();
      return;
    }
  }
  term = get_name();    // the request that terminates the definition
  if (term.is_null())
    term = dot_symbol;
  while (!tok.newline() && !tok.eof())
    tok.next();
  const char *start_filename;
  int start_lineno;
  int have_start_location = input_stack::get_location(0, &start_filename,
                                                      &start_lineno);
  node *n;
  // doing this here makes the line numbers come out right
  int c = get_copy(&n, 1);
  macro mac;
  macro *mm = 0;
  if (mode == DEFINE_NORMAL || mode == DEFINE_APPEND) {
    request_or_macro *rm =
      (request_or_macro *)request_dictionary.lookup(nm);
    if (rm)
      mm = rm->to_macro();
    if (mm && mode == DEFINE_APPEND)
      mac = *mm;
  }
  int bol = 1;
  if (comp == COMP_DISABLE)
    mac.append(PUSH_GROFF_MODE);
  else if (comp == COMP_ENABLE)
    mac.append(PUSH_COMP_MODE);
  for (;;) {
    if (c == '\n')
      mac.clear_string_flag();
    while (c == ESCAPE_NEWLINE) {
      if (mode == DEFINE_NORMAL || mode == DEFINE_APPEND)
        mac.append(c);
      c = get_copy(&n, 1);
    }
    if (bol && c == '.') {
      const char *s = term.contents();
      int d = 0;
      // see if it matches term
      int i = 0;
      if (s[0] != 0) {
        while ((d = get_copy(&n)) == ' ' || d == '\t')
          ;
        if ((unsigned char)s[0] == d) {
          for (i = 1; s[i] != 0; i++) {
            d = get_copy(&n);
            if ((unsigned char)s[i] != d)
              break;
          }
        }
      }
      if (s[i] == 0
          && ((i == 2 && compatible_flag)
              || (d = get_copy(&n)) == ' '
              || d == '\n')) {  // we found it
        if (d == '\n')
          tok.make_newline();
        else
          tok.make_space();
        if (mode == DEFINE_APPEND || mode == DEFINE_NORMAL) {
          if (!mm) {
            mm = new macro;
            request_dictionary.define(nm, mm);
          }
          if (comp == COMP_DISABLE || comp == COMP_ENABLE)
            mac.append(POP_GROFFCOMP_MODE);
          *mm = mac;
        }
        if (term != dot_symbol) {
          ignoring = 0;
          interpolate_macro(term);
        }
        else
          skip_line();
        return;
      }
      if (mode == DEFINE_APPEND || mode == DEFINE_NORMAL) {
        mac.append(c);
        for (int j = 0; j < i; j++)
          mac.append(s[j]);
      }
      c = d;
    }
    if (c == EOF) {
      if (mode == DEFINE_NORMAL || mode == DEFINE_APPEND) {
        if (have_start_location)
          error_with_file_and_line(start_filename, start_lineno,
                                   "end of file while defining macro `%1'",
                                   nm.contents());
        else
          error("end of file while defining macro `%1'", nm.contents());
      }
      else {
        if (have_start_location)
          error_with_file_and_line(start_filename, start_lineno,
                                   "end of file while ignoring input lines");
        else
          error("end of file while ignoring input lines");
      }
      tok.next();
      return;
    }
    if (mode == DEFINE_NORMAL || mode == DEFINE_APPEND) {
      if (c == 0)
        mac.append(n);
      else
        mac.append(c);
    }
    bol = (c == '\n');
    c = get_copy(&n, 1);
  }
}

void define_macro()
{
  do_define_macro(DEFINE_NORMAL, CALLING_NORMAL,
                  compatible_flag ? COMP_ENABLE : COMP_IGNORE);
}

void define_nocomp_macro()
{
  do_define_macro(DEFINE_NORMAL, CALLING_NORMAL, COMP_DISABLE);
}

void define_indirect_macro()
{
  do_define_macro(DEFINE_NORMAL, CALLING_INDIRECT,
                  compatible_flag ? COMP_ENABLE : COMP_IGNORE);
}

void define_indirect_nocomp_macro()
{
  do_define_macro(DEFINE_NORMAL, CALLING_INDIRECT, COMP_DISABLE);
}

void append_macro()
{
  do_define_macro(DEFINE_APPEND, CALLING_NORMAL,
                  compatible_flag ? COMP_ENABLE : COMP_IGNORE);
}

void append_nocomp_macro()
{
  do_define_macro(DEFINE_APPEND, CALLING_NORMAL, COMP_DISABLE);
}

void append_indirect_macro()
{
  do_define_macro(DEFINE_APPEND, CALLING_INDIRECT,
                  compatible_flag ? COMP_ENABLE : COMP_IGNORE);
}

void append_indirect_nocomp_macro()
{
  do_define_macro(DEFINE_APPEND, CALLING_INDIRECT, COMP_DISABLE);
}

void ignore()
{
  ignoring = 1;
  do_define_macro(DEFINE_IGNORE, CALLING_NORMAL, COMP_IGNORE);
  ignoring = 0;
}

void remove_macro()
{
  for (;;) {
    symbol s = get_name();
    if (s.is_null())
      break;
    request_dictionary.remove(s);
  }
  skip_line();
}

void rename_macro()
{
  symbol s1 = get_name(1);
  if (!s1.is_null()) {
    symbol s2 = get_name(1);
    if (!s2.is_null())
      request_dictionary.rename(s1, s2);
  }
  skip_line();
}

void alias_macro()
{
  symbol s1 = get_name(1);
  if (!s1.is_null()) {
    symbol s2 = get_name(1);
    if (!s2.is_null()) {
      if (!request_dictionary.alias(s1, s2))
        warning(WARN_MAC, "macro `%1' not defined", s2.contents());
    }
  }
  skip_line();
}

void chop_macro()
{
  symbol s = get_name(1);
  if (!s.is_null()) {
    request_or_macro *p = lookup_request(s);
    macro *m = p->to_macro();
    if (!m)
      error("cannot chop request");
    else if (m->empty())
      error("cannot chop empty macro");
    else {
      int have_restore = 0;
      // we have to check for additional save/restore pairs which could be
      // there due to empty am1 requests.
      for (;;) {
        if (m->get(m->len - 1) != POP_GROFFCOMP_MODE)
          break;
        have_restore = 1;
        m->len -= 1;
        if (m->get(m->len - 1) != PUSH_GROFF_MODE
            && m->get(m->len - 1) != PUSH_COMP_MODE)
          break;
        have_restore = 0;
        m->len -= 1;
        if (m->len == 0)
          break;
      }
      if (m->len == 0)
        error("cannot chop empty macro");
      else {
        if (have_restore)
          m->set(POP_GROFFCOMP_MODE, m->len - 1);
        else
          m->len -= 1;
      }
    }
  }
  skip_line();
}

void substring_request()
{
  int start;                            // 0, 1, ..., n-1  or  -1, -2, ...
  symbol s = get_name(1);
  if (!s.is_null() && get_integer(&start)) {
    request_or_macro *p = lookup_request(s);
    macro *m = p->to_macro();
    if (!m)
      error("cannot apply `substring' on a request");
    else {
      int end = -1;
      if (!has_arg() || get_integer(&end)) {
        int real_length = 0;                    // 1, 2, ..., n
        string_iterator iter1(*m);
        for (int l = 0; l < m->len; l++) {
          int c = iter1.get(0);
          if (c == PUSH_GROFF_MODE
              || c == PUSH_COMP_MODE
              || c == POP_GROFFCOMP_MODE)
            continue;
          if (c == EOF)
            break;
          real_length++;
        }
        if (start < 0)
          start += real_length;
        if (end < 0)
          end += real_length;
        if (start > end) {
          int tem = start;
          start = end;
          end = tem;
        }
        if (start >= real_length || end < 0) {
          warning(WARN_RANGE,
                  "start and end index of substring out of range");
          m->len = 0;
          if (m->p) {
            if (--(m->p->count) <= 0)
              delete m->p;
            m->p = 0;
          }
          skip_line();
          return;
        }
        if (start < 0) {
          warning(WARN_RANGE,
                  "start index of substring out of range, set to 0");
          start = 0;
        }
        if (end >= real_length) {
          warning(WARN_RANGE,
                  "end index of substring out of range, set to string length");
          end = real_length - 1;
        }
        // now extract the substring
        string_iterator iter(*m);
        int i;
        for (i = 0; i < start; i++) {
          int c = iter.get(0);
          while (c == PUSH_GROFF_MODE
                 || c == PUSH_COMP_MODE
                 || c == POP_GROFFCOMP_MODE)
            c = iter.get(0);
          if (c == EOF)
            break;
        }
        macro mac;
        for (; i <= end; i++) {
          node *nd = 0;         // pacify compiler
          int c = iter.get(&nd);
          while (c == PUSH_GROFF_MODE
                 || c == PUSH_COMP_MODE
                 || c == POP_GROFFCOMP_MODE)
            c = iter.get(0);
          if (c == EOF)
            break;
          if (c == 0)
            mac.append(nd);
          else
            mac.append((unsigned char)c);
        }
        *m = mac;
      }
    }
  }
  skip_line();
}

void length_request()
{
  symbol ret;
  ret = get_name(1);
  if (ret.is_null()) {
    skip_line();
    return;
  }
  int c;
  node *n;
  if (tok.newline())
    c = '\n';
  else if (tok.tab())
    c = '\t';
  else if (!tok.space()) {
    error("bad string definition");
    skip_line();
    return;
  }
  else
    c = get_copy(&n);
  while (c == ' ')
    c = get_copy(&n);
  if (c == '"')
    c = get_copy(&n);
  int len = 0;
  while (c != '\n' && c != EOF) {
    ++len;
    c = get_copy(&n);
  }
  reg *r = (reg*)number_reg_dictionary.lookup(ret);
  if (r)
    r->set_value(len);
  else
    set_number_reg(ret, len);
  tok.next();
}

void asciify_macro()
{
  symbol s = get_name(1);
  if (!s.is_null()) {
    request_or_macro *p = lookup_request(s);
    macro *m = p->to_macro();
    if (!m)
      error("cannot asciify request");
    else {
      macro am;
      string_iterator iter(*m);
      for (;;) {
        node *nd = 0;           // pacify compiler
        int c = iter.get(&nd);
        if (c == EOF)
          break;
        if (c != 0)
          am.append(c);
        else
          nd->asciify(&am);
      }
      *m = am;
    }
  }
  skip_line();
}

void unformat_macro()
{
  symbol s = get_name(1);
  if (!s.is_null()) {
    request_or_macro *p = lookup_request(s);
    macro *m = p->to_macro();
    if (!m)
      error("cannot unformat request");
    else {
      macro am;
      string_iterator iter(*m);
      for (;;) {
        node *nd = 0;           // pacify compiler
        int c = iter.get(&nd);
        if (c == EOF)
          break;
        if (c != 0)
          am.append(c);
        else {
          if (nd->set_unformat_flag())
            am.append(nd);
        }
      }
      *m = am;
    }
  }
  skip_line();
}

static void interpolate_environment_variable(symbol nm)
{
  const char *s = getenv(nm.contents());
  if (s && *s)
    input_stack::push(make_temp_iterator(s));
}

void interpolate_number_reg(symbol nm, int inc)
{
  reg *r = lookup_number_reg(nm);
  if (inc < 0)
    r->decrement();
  else if (inc > 0)
    r->increment();
  input_stack::push(make_temp_iterator(r->get_string()));
}

static void interpolate_number_format(symbol nm)
{
  reg *r = (reg *)number_reg_dictionary.lookup(nm);
  if (r)
    input_stack::push(make_temp_iterator(r->get_format()));
}

static int get_delim_number(units *n, unsigned char si, int prev_value)
{
  token start;
  start.next();
  if (start.delimiter(1)) {
    tok.next();
    if (get_number(n, si, prev_value)) {
      if (start != tok)
        warning(WARN_DELIM, "closing delimiter does not match");
      return 1;
    }
  }
  return 0;
}

static int get_delim_number(units *n, unsigned char si)
{
  token start;
  start.next();
  if (start.delimiter(1)) {
    tok.next();
    if (get_number(n, si)) {
      if (start != tok)
        warning(WARN_DELIM, "closing delimiter does not match");
      return 1;
    }
  }
  return 0;
}

static int get_line_arg(units *n, unsigned char si, charinfo **cp)
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  if (!start.delimiter(1))
    return 0;
  tok.next();
  if (get_number(n, si)) {
    if (tok.dummy() || tok.transparent_dummy())
      tok.next();
    if (!(start == tok && input_stack::get_level() == start_level)) {
      *cp = tok.get_char(1);
      tok.next();
    }
    if (!(start == tok && input_stack::get_level() == start_level))
      warning(WARN_DELIM, "closing delimiter does not match");
    return 1;
  }
  return 0;
}

static int read_size(int *x)
{
  tok.next();
  int c = tok.ch();
  int inc = 0;
  if (c == '-') {
    inc = -1;
    tok.next();
    c = tok.ch();
  }
  else if (c == '+') {
    inc = 1;
    tok.next();
    c = tok.ch();
  }
  int val = 0;          // pacify compiler
  int bad = 0;
  if (c == '(') {
    tok.next();
    c = tok.ch();
    if (!inc) {
      // allow an increment either before or after the left parenthesis
      if (c == '-') {
        inc = -1;
        tok.next();
        c = tok.ch();
      }
      else if (c == '+') {
        inc = 1;
        tok.next();
        c = tok.ch();
      }
    }
    if (!csdigit(c))
      bad = 1;
    else {
      val = c - '0';
      tok.next();
      c = tok.ch();
      if (!csdigit(c))
        bad = 1;
      else {
        val = val*10 + (c - '0');
        val *= sizescale;
      }
    }
  }
  else if (csdigit(c)) {
    val = c - '0';
    if (!inc && c != '0' && c < '4') {
      tok.next();
      c = tok.ch();
      if (!csdigit(c))
        bad = 1;
      else
        val = val*10 + (c - '0');
    }
    val *= sizescale;
  }
  else if (!tok.delimiter(1))
    return 0;
  else {
    token start(tok);
    tok.next();
    c = tok.ch();
    if (!inc && (c == '-' || c == '+')) {
      inc = c == '+' ? 1 : -1;
      tok.next();
    }
    if (!get_number(&val, 'z'))
      return 0;
    if (!(start.ch() == '[' && tok.ch() == ']') && start != tok) {
      if (start.ch() == '[')
        error("missing `]'");
      else
        error("missing closing delimiter");
      return 0;
    }
  }
  if (!bad) {
    switch (inc) {
    case 0:
      if (val == 0) {
        // special case -- \s[0] and \s0 means to revert to previous size
        *x = 0;
        return 1;
      }
      *x = val;
      break;
    case 1:
      *x = curenv->get_requested_point_size() + val;
      break;
    case -1:
      *x = curenv->get_requested_point_size() - val;
      break;
    default:
      assert(0);
    }
    if (*x <= 0) {
      warning(WARN_RANGE,
              "\\s escape results in non-positive point size; set to 1");
      *x = 1;
    }
    return 1;
  }
  else {
    error("bad digit in point size");
    return 0;
  }
}

static symbol get_delim_name()
{
  token start;
  start.next();
  if (start.eof()) {
    error("end of input at start of delimited name");
    return NULL_SYMBOL;
  }
  if (start.newline()) {
    error("can't delimit name with a newline");
    return NULL_SYMBOL;
  }
  int start_level = input_stack::get_level();
  char abuf[ABUF_SIZE];
  char *buf = abuf;
  int buf_size = ABUF_SIZE;
  int i = 0;
  for (;;) {
    if (i + 1 > buf_size) {
      if (buf == abuf) {
        buf = new char[ABUF_SIZE*2];
        memcpy(buf, abuf, buf_size);
        buf_size = ABUF_SIZE*2;
      }
      else {
        char *old_buf = buf;
        buf = new char[buf_size*2];
        memcpy(buf, old_buf, buf_size);
        buf_size *= 2;
        a_delete old_buf;
      }
    }
    tok.next();
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    if ((buf[i] = tok.ch()) == 0) {
      error("missing delimiter (got %1)", tok.description());
      if (buf != abuf)
        a_delete buf;
      return NULL_SYMBOL;
    }
    i++;
  }
  buf[i] = '\0';
  if (buf == abuf) {
    if (i == 0) {
      error("empty delimited name");
      return NULL_SYMBOL;
    }
    else
      return symbol(buf);
  }
  else {
    symbol s(buf);
    a_delete buf;
    return s;
  }
}

// Implement \R

static void do_register()
{
  token start;
  start.next();
  if (!start.delimiter(1))
    return;
  tok.next();
  symbol nm = get_long_name(1);
  if (nm.is_null())
    return;
  while (tok.space())
    tok.next();
  reg *r = (reg *)number_reg_dictionary.lookup(nm);
  int prev_value;
  if (!r || !r->get_value(&prev_value))
    prev_value = 0;
  int val;
  if (!get_number(&val, 'u', prev_value))
    return;
  if (start != tok)
    warning(WARN_DELIM, "closing delimiter does not match");
  if (r)
    r->set_value(val);
  else
    set_number_reg(nm, val);
}

// this implements the \w escape sequence

static void do_width()
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  environment env(curenv);
  environment *oldenv = curenv;
  curenv = &env;
  for (;;) {
    tok.next();
    if (tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      break;
    }
    if (tok.newline()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    if (tok == start
        && (compatible_flag || input_stack::get_level() == start_level))
      break;
    tok.process();
  }
  env.wrap_up_tab();
  units x = env.get_input_line_position().to_units();
  input_stack::push(make_temp_iterator(i_to_a(x)));
  env.width_registers();
  curenv = oldenv;
  have_input = 0;
}

charinfo *page_character;

void set_page_character()
{
  page_character = get_optional_char();
  skip_line();
}

static const symbol percent_symbol("%");

void read_title_parts(node **part, hunits *part_width)
{
  tok.skip();
  if (tok.newline() || tok.eof())
    return;
  token start(tok);
  int start_level = input_stack::get_level();
  tok.next();
  for (int i = 0; i < 3; i++) {
    while (!tok.newline() && !tok.eof()) {
      if (tok == start
          && (compatible_flag || input_stack::get_level() == start_level)) {
        tok.next();
        break;
      }
      if (page_character != 0 && tok.get_char() == page_character)
        interpolate_number_reg(percent_symbol, 0);
      else
        tok.process();
      tok.next();
    }
    curenv->wrap_up_tab();
    part_width[i] = curenv->get_input_line_position();
    part[i] = curenv->extract_output_line();
  }
  while (!tok.newline() && !tok.eof())
    tok.next();
}

class non_interpreted_node : public node {
  macro mac;
public:
  non_interpreted_node(const macro &);
  int interpret(macro *);
  node *copy();
  int ends_sentence();
  int same(node *);
  const char *type();
  int force_tprint();
  int is_tag();
};

non_interpreted_node::non_interpreted_node(const macro &m) : mac(m)
{
}

int non_interpreted_node::ends_sentence()
{
  return 2;
}

int non_interpreted_node::same(node *nd)
{
  return mac == ((non_interpreted_node *)nd)->mac;
}

const char *non_interpreted_node::type()
{
  return "non_interpreted_node";
}

int non_interpreted_node::force_tprint()
{
  return 0;
}

int non_interpreted_node::is_tag()
{
  return 0;
}

node *non_interpreted_node::copy()
{
  return new non_interpreted_node(mac);
}

int non_interpreted_node::interpret(macro *m)
{
  string_iterator si(mac);
  node *n = 0;          // pacify compiler
  for (;;) {
    int c = si.get(&n);
    if (c == EOF)
      break;
    if (c == 0)
      m->append(n);
    else
      m->append(c);
  }
  return 1;
}

static node *do_non_interpreted()
{
  node *n;
  int c;
  macro mac;
  while ((c = get_copy(&n)) != ESCAPE_QUESTION && c != EOF && c != '\n')
    if (c == 0)
      mac.append(n);
    else
      mac.append(c);
  if (c == EOF || c == '\n') {
    error("missing \\?");
    return 0;
  }
  return new non_interpreted_node(mac);
}

static void encode_char(macro *mac, char c)
{
  if (c == '\0') {
    if ((font::use_charnames_in_special) && tok.special()) {
      charinfo *ci = tok.get_char(1);
      const char *s = ci->get_symbol()->contents();
      if (s[0] != (char)0) {
        mac->append('\\');
        mac->append('[');
        int i = 0;
        while (s[i] != (char)0) {
          mac->append(s[i]);
          i++;
        }
        mac->append(']');
      }
    }
    else if (tok.stretchable_space()
             || tok.unstretchable_space())
      mac->append(' ');
    else if (!(tok.hyphen_indicator()
               || tok.dummy()
               || tok.transparent_dummy()
               || tok.zero_width_break()))
      error("%1 is invalid within \\X", tok.description());
  }
  else {
    if ((font::use_charnames_in_special) && (c == '\\')) {
      /*
       * add escape escape sequence
       */
      mac->append(c);
    }
    mac->append(c);
  }
}

node *do_special()
{
  token start;
  start.next();
  int start_level = input_stack::get_level();
  macro mac;
  for (tok.next();
       tok != start || input_stack::get_level() != start_level;
       tok.next()) {
    if (tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      return 0;
    }
    if (tok.newline()) {
      input_stack::push(make_temp_iterator("\n"));
      warning(WARN_DELIM, "missing closing delimiter");
      break;
    }
    unsigned char c;
    if (tok.space())
      c = ' ';
    else if (tok.tab())
      c = '\t';
    else if (tok.leader())
      c = '\001';
    else if (tok.backspace())
      c = '\b';
    else
      c = tok.ch();
    encode_char(&mac, c);
  }
  return new special_node(mac);
}

void device_request()
{
  if (!tok.newline() && !tok.eof()) {
    int c;
    macro mac;
    for (;;) {
      c = get_copy(0);
      if (c == '"') {
        c = get_copy(0);
        break;
      }
      if (c != ' ' && c != '\t')
        break;
    }
    for (; c != '\n' && c != EOF; c = get_copy(0))
      mac.append(c);
    curenv->add_node(new special_node(mac));
  }
  tok.next();
}

void device_macro_request()
{
  symbol s = get_name(1);
  if (!(s.is_null() || s.is_empty())) {
    request_or_macro *p = lookup_request(s);
    macro *m = p->to_macro();
    if (m)
      curenv->add_node(new special_node(*m));
    else 
      error("can't transparently throughput a request");
  }
  skip_line();
}

void output_request()
{
  if (!tok.newline() && !tok.eof()) {
    int c;
    for (;;) {
      c = get_copy(0);
      if (c == '"') {
        c = get_copy(0);
        break;
      }
      if (c != ' ' && c != '\t')
        break;
    }
    for (; c != '\n' && c != EOF; c = get_copy(0))
      topdiv->transparent_output(c);
    topdiv->transparent_output('\n');
  }
  tok.next();
}

extern int image_no;            // from node.cpp

static node *do_suppress(symbol nm)
{
  if (nm.is_null() || nm.is_empty()) {
    error("expecting an argument to escape \\O");
    return 0;
  }
  const char *s = nm.contents();
  switch (*s) {
  case '0':
    if (begin_level == 0)
      // suppress generation of glyphs
      return new suppress_node(0, 0);
    break;
  case '1':
    if (begin_level == 0)
      // enable generation of glyphs
      return new suppress_node(1, 0);
    break;
  case '2':
    if (begin_level == 0)
      return new suppress_node(1, 1);
    break;
  case '3':
    have_input = 1;
    begin_level++;
    break;
  case '4':
    have_input = 1;
    begin_level--;
    break;
  case '5':
    {
      s++;                      // move over '5'
      char position = *s;
      if (*s == (char)0) {
        error("missing position and filename in \\O");
        return 0;
      }
      if (!(position == 'l'
            || position == 'r'
            || position == 'c'
            || position == 'i')) {
        error("l, r, c, or i position expected (got %1 in \\O)", position);
        return 0;
      }
      s++;                      // onto image name
      if (s == (char *)0) {
        error("missing image name for \\O");
        return 0;
      }
      image_no++;
      if (begin_level == 0)
        return new suppress_node(symbol(s), position, image_no);
      else
        have_input = 1;
    }
    break;
  default:
    error("`%1' is an invalid argument to \\O", *s);
  }
  return 0;
}

void special_node::tprint(troff_output_file *out)
{
  tprint_start(out);
  string_iterator iter(mac);
  for (;;) {
    int c = iter.get(0);
    if (c == EOF)
      break;
    for (const char *s = ::asciify(c); *s; s++)
      tprint_char(out, *s);
  }
  tprint_end(out);
}

int get_file_line(const char **filename, int *lineno)
{
  return input_stack::get_location(0, filename, lineno);
}

void line_file()
{
  int n;
  if (get_integer(&n)) {
    const char *filename = 0;
    if (has_arg()) {
      symbol s = get_long_name();
      filename = s.contents();
    }
    (void)input_stack::set_location(filename, n-1);
  }
  skip_line();
}

static int nroff_mode = 0;

static void nroff_request()
{
  nroff_mode = 1;
  skip_line();
}

static void troff_request()
{
  nroff_mode = 0;
  skip_line();
}

static void skip_alternative()
{
  int level = 0;
  // ensure that ``.if 0\{'' works as expected
  if (tok.left_brace())
    level++;
  int c;
  for (;;) {
    c = input_stack::get(0);
    if (c == EOF)
      break;
    if (c == ESCAPE_LEFT_BRACE)
      ++level;
    else if (c == ESCAPE_RIGHT_BRACE)
      --level;
    else if (c == escape_char && escape_char > 0)
      switch(input_stack::get(0)) {
      case '{':
        ++level;
        break;
      case '}':
        --level;
        break;
      case '"':
        while ((c = input_stack::get(0)) != '\n' && c != EOF)
          ;
      }
    /*
      Note that the level can properly be < 0, eg
        
        .if 1 \{\
        .if 0 \{\
        .\}\}

      So don't give an error message in this case.
    */
    if (level <= 0 && c == '\n')
      break;
  }
  tok.next();
}

static void begin_alternative()
{
  while (tok.space() || tok.left_brace())
    tok.next();
}

void nop_request()
{
  while (tok.space())
    tok.next();
}

static int_stack if_else_stack;

int do_if_request()
{
  int invert = 0;
  while (tok.space())
    tok.next();
  while (tok.ch() == '!') {
    tok.next();
    invert = !invert;
  }
  int result;
  unsigned char c = tok.ch();
  if (c == 't') {
    tok.next();
    result = !nroff_mode;
  }
  else if (c == 'n') {
    tok.next();
    result = nroff_mode;
  }
  else if (c == 'v') {
    tok.next();
    result = 0;
  }
  else if (c == 'o') {
    result = (topdiv->get_page_number() & 1);
    tok.next();
  }
  else if (c == 'e') {
    result = !(topdiv->get_page_number() & 1);
    tok.next();
  }
  else if (c == 'd' || c == 'r') {
    tok.next();
    symbol nm = get_name(1);
    if (nm.is_null()) {
      skip_alternative();
      return 0;
    }
    result = (c == 'd'
              ? request_dictionary.lookup(nm) != 0
              : number_reg_dictionary.lookup(nm) != 0);
  }
  else if (c == 'm') {
    tok.next();
    symbol nm = get_long_name(1);
    if (nm.is_null()) {
      skip_alternative();
      return 0;
    }
    result = (nm == default_symbol
              || color_dictionary.lookup(nm) != 0);
  }
  else if (c == 'c') {
    tok.next();
    tok.skip();
    charinfo *ci = tok.get_char(1);
    if (ci == 0) {
      skip_alternative();
      return 0;
    }
    result = character_exists(ci, curenv);
    tok.next();
  }
  else if (c == 'F') {
    tok.next();
    symbol nm = get_long_name(1);
    if (nm.is_null()) {
      skip_alternative();
      return 0;
    }
    result = check_font(curenv->get_family()->nm, nm);
  }
  else if (c == 'S') {
    tok.next();
    symbol nm = get_long_name(1);
    if (nm.is_null()) {
      skip_alternative();
      return 0;
    }
    result = check_style(nm);
  }
  else if (tok.space())
    result = 0;
  else if (tok.delimiter()) {
    token delim = tok;
    int delim_level = input_stack::get_level();
    environment env1(curenv);
    environment env2(curenv);
    environment *oldenv = curenv;
    curenv = &env1;
    suppress_push = 1;
    for (int i = 0; i < 2; i++) {
      for (;;) {
        tok.next();
        if (tok.newline() || tok.eof()) {
          warning(WARN_DELIM, "missing closing delimiter");
          tok.next();
          curenv = oldenv;
          return 0;
        }
        if (tok == delim
            && (compatible_flag || input_stack::get_level() == delim_level))
          break;
        tok.process();
      }
      curenv = &env2;
    }
    node *n1 = env1.extract_output_line();
    node *n2 = env2.extract_output_line();
    result = same_node_list(n1, n2);
    delete_node_list(n1);
    delete_node_list(n2);
    curenv = oldenv;
    have_input = 0;
    suppress_push = 0;
    tok.next();
  }
  else {
    units n;
    if (!get_number(&n, 'u')) {
      skip_alternative();
      return 0;
    }
    else
      result = n > 0;
  }
  if (invert)
    result = !result;
  if (result)
    begin_alternative();
  else
    skip_alternative();
  return result;
}

void if_else_request()
{
  if_else_stack.push(do_if_request());
}

void if_request()
{
  do_if_request();
}

void else_request()
{
  if (if_else_stack.is_empty()) {
    warning(WARN_EL, "unbalanced .el request");
    skip_alternative();
  }
  else {
    if (if_else_stack.pop())
      skip_alternative();
    else
      begin_alternative();
  }
}

static int while_depth = 0;
static int while_break_flag = 0;

void while_request()
{
  macro mac;
  int escaped = 0;
  int level = 0;
  mac.append(new token_node(tok));
  for (;;) {
    node *n = 0;                // pacify compiler
    int c = input_stack::get(&n);
    if (c == EOF)
      break;
    if (c == 0) {
      escaped = 0;
      mac.append(n);
    }
    else if (escaped) {
      if (c == '{')
        level += 1;
      else if (c == '}')
        level -= 1;
      escaped = 0;
      mac.append(c);
    }
    else {
      if (c == ESCAPE_LEFT_BRACE)
        level += 1;
      else if (c == ESCAPE_RIGHT_BRACE)
        level -= 1;
      else if (c == escape_char)
        escaped = 1;
      mac.append(c);
      if (c == '\n' && level <= 0)
        break;
    }
  }
  if (level != 0)
    error("unbalanced \\{ \\}");
  else {
    while_depth++;
    input_stack::add_boundary();
    for (;;) {
      input_stack::push(new string_iterator(mac, "while loop"));
      tok.next();
      if (!do_if_request()) {
        while (input_stack::get(0) != EOF)
          ;
        break;
      }
      process_input_stack();
      if (while_break_flag || input_stack::is_return_boundary()) {
        while_break_flag = 0;
        break;
      }
    }
    input_stack::remove_boundary();
    while_depth--;
  }
  tok.next();
}

void while_break_request()
{
  if (!while_depth) {
    error("no while loop");
    skip_line();
  }
  else {
    while_break_flag = 1;
    while (input_stack::get(0) != EOF)
      ;
    tok.next();
  }
}

void while_continue_request()
{
  if (!while_depth) {
    error("no while loop");
    skip_line();
  }
  else {
    while (input_stack::get(0) != EOF)
      ;
    tok.next();
  }
}

// .so

void source()
{
  symbol nm = get_long_name(1);
  if (nm.is_null())
    skip_line();
  else {
    while (!tok.newline() && !tok.eof())
      tok.next();
    file_case *fcp = include_search_path.open_file_cautious(nm.contents(),
        fcp->mux_unpack);
    if (fcp != NULL)
      input_stack::push(new file_iterator(fcp, nm.contents()));
    else
      error("can't open `%1': %2", nm.contents(), strerror(errno));
    tok.next();
  }
}

// like .so but use popen()

void pipe_source()
{
  if (!unsafe_flag) {
    error(".pso request not allowed in safer mode");
    skip_line();
  }
  else {
#ifdef POPEN_MISSING
    error("pipes not available on this system");
    skip_line();
#else /* not POPEN_MISSING */
    if (tok.newline() || tok.eof())
      error("missing command");
    else {
      int c;
      while ((c = get_copy(0)) == ' ' || c == '\t')
        ;
      int buf_size = 24;
      char *buf = new char[buf_size];
      int buf_used = 0;
      for (; c != '\n' && c != EOF; c = get_copy(0)) {
        const char *s = asciify(c);
        int slen = strlen(s);
        if (buf_used + slen + 1> buf_size) {
          char *old_buf = buf;
          int old_buf_size = buf_size;
          buf_size *= 2;
          buf = new char[buf_size];
          memcpy(buf, old_buf, old_buf_size);
          a_delete old_buf;
        }
        strcpy(buf + buf_used, s);
        buf_used += slen;
      }
      buf[buf_used] = '\0';
      errno = 0;
      FILE *fp = popen(buf, POPEN_RT);
      if (fp != NULL)
        input_stack::push(new file_iterator(
          new file_case(fp, buf, file_case::fc_pipe | file_case::fc_take_path),
                symbol(buf).contents()));
      else {
        error("can't open pipe to process `%1': %2", buf, strerror(errno));
        a_delete buf;
      }
    }
    tok.next();
#endif /* not POPEN_MISSING */
  }
}

// .psbb

static int llx_reg_contents = 0;
static int lly_reg_contents = 0;
static int urx_reg_contents = 0;
static int ury_reg_contents = 0;

struct bounding_box {
  int llx, lly, urx, ury;
};

/* Parse the argument to a %%BoundingBox comment.  Return 1 if it
contains 4 numbers, 2 if it contains (atend), 0 otherwise. */

int parse_bounding_box(char *p, bounding_box *bb)
{
  if (sscanf(p, "%d %d %d %d",
             &bb->llx, &bb->lly, &bb->urx, &bb->ury) == 4)
    return 1;
  else {
    /* The Document Structuring Conventions say that the numbers
       should be integers.  Unfortunately some broken applications
       get this wrong. */
    double x1, x2, x3, x4;
    if (sscanf(p, "%lf %lf %lf %lf", &x1, &x2, &x3, &x4) == 4) {
      bb->llx = (int)x1;
      bb->lly = (int)x2;
      bb->urx = (int)x3;
      bb->ury = (int)x4;
      return 1;
    }
    else {
      for (; *p == ' ' || *p == '\t'; p++)
        ;
      if (strncmp(p, "(atend)", 7) == 0) {
        return 2;
      }
    }
  }
  bb->llx = bb->lly = bb->urx = bb->ury = 0;
  return 0;
}

// This version is taken from psrm.cpp

#define PS_LINE_MAX 255
cset white_space("\n\r \t");

int ps_get_line(char *buf, file_case *fcp, const char* filename)
{
  int c = fcp->get_c();
  if (c == EOF) {
    buf[0] = '\0';
    return 0;
  }
  int i = 0;
  int err = 0;
  while (c != '\r' && c != '\n' && c != EOF) {
    if ((c < 0x1b && !white_space(c)) || c == 0x7f)
      error("invalid input character code %1 in `%2'", int(c), filename);
    else if (i < PS_LINE_MAX)
      buf[i++] = c;
    else if (!err) {
      err = 1;
      error("PostScript file `%1' is non-conforming "
            "because length of line exceeds 255", filename);
    }
    c = fcp->get_c();
  }
  buf[i++] = '\n';
  buf[i] = '\0';
  if (c == '\r') {
    c = fcp->get_c();
    if (c != EOF && c != '\n')
      fcp->unget_c(c);
  }
  return 1;
}

inline void assign_registers(int llx, int lly, int urx, int ury)
{
  llx_reg_contents = llx;
  lly_reg_contents = lly;
  urx_reg_contents = urx;
  ury_reg_contents = ury;
}

void do_ps_file(file_case *fcp, const char* filename)
{
  bounding_box bb;
  int bb_at_end = 0;
  char buf[PS_LINE_MAX];
  llx_reg_contents = lly_reg_contents =
    urx_reg_contents = ury_reg_contents = 0;
  if (!ps_get_line(buf, fcp, filename)) {
    error("`%1' is empty", filename);
    return;
  }
  if (strncmp("%!PS-Adobe-", buf, 11) != 0) {
    error("`%1' is not conforming to the Document Structuring Conventions",
          filename);
    return;
  }
  while (ps_get_line(buf, fcp, filename) != 0) {
    // in header comments, `%X' (`X' any printable character except
    // whitespace) is possible too
    if (buf[0] == '%') {
      if (strncmp(buf + 1, "%EndComments", 12) == 0)
        break;
      if (white_space(buf[1]))
        break;
    }
    else
      break;
    if (strncmp(buf + 1, "%BoundingBox:", 13) == 0) {
      int res = parse_bounding_box(buf + 14, &bb);
      if (res == 1) {
        assign_registers(bb.llx, bb.lly, bb.urx, bb.ury);
        return;
      }
      else if (res == 2) {
        bb_at_end = 1;
        break;
      }
      else {
        error("the arguments to the %%%%BoundingBox comment in `%1' are bad",
              filename);
        return;
      }
    }
  }
  if (bb_at_end) {
    long offset;
    int last_try = 0;
    // in the trailer, the last BoundingBox comment is significant
    for (offset = 512; !last_try; offset *= 2) {
      int had_trailer = 0;
      int got_bb = 0;
      if (offset > 32768 || fcp->seek(-offset, fcp->seek_end) == -1) {
        last_try = 1;
        if (fcp->seek(0L, fcp->seek_set) == -1)
          break;
      }
      while (ps_get_line(buf, fcp, filename) != 0) {
        if (buf[0] == '%' && buf[1] == '%') {
          if (!had_trailer) {
            if (strncmp(buf + 2, "Trailer", 7) == 0)
              had_trailer = 1;
          }
          else {
            if (strncmp(buf + 2, "BoundingBox:", 12) == 0) {
              int res = parse_bounding_box(buf + 14, &bb);
              if (res == 1)
                got_bb = 1;
              else if (res == 2) {
                error("`(atend)' not allowed in trailer of `%1'", filename);
                return;
              }
              else {
                error("the arguments to the %%%%BoundingBox comment in `%1' are bad",
                      filename);
                return;
              }
            }
          }
        }
      }
      if (got_bb) {
        assign_registers(bb.llx, bb.lly, bb.urx, bb.ury);
        return;
      }
    }
  }
  error("%%%%BoundingBox comment not found in `%1'", filename);
}

void ps_bbox_request()
{
  symbol nm = get_long_name(1);
  if (nm.is_null())
    skip_line();
  else {
    while (!tok.newline() && !tok.eof())
      tok.next();
    // PS files might contain non-printable characters, such as ^Z
    // and CRs not followed by an LF, so open them in binary mode.
    file_case *fcp = include_search_path.open_file_cautious(nm.contents(),
        fcp->mux_need_seek | fcp->mux_need_binary);
    if (fcp != NULL) {
      do_ps_file(fcp, nm.contents());
      delete fcp;
    } else
      error("can't open `%1': %2", nm.contents(), strerror(errno));
    tok.next();
  }
}

const char *asciify(int c)
{
  static char buf[3];
  buf[0] = escape_char == '\0' ? '\\' : escape_char;
  buf[1] = buf[2] = '\0';
  switch (c) {
  case ESCAPE_QUESTION:
    buf[1] = '?';
    break;
  case ESCAPE_AMPERSAND:
    buf[1] = '&';
    break;
  case ESCAPE_RIGHT_PARENTHESIS:
    buf[1] = ')';
    break;
  case ESCAPE_UNDERSCORE:
    buf[1] = '_';
    break;
  case ESCAPE_BAR:
    buf[1] = '|';
    break;
  case ESCAPE_CIRCUMFLEX:
    buf[1] = '^';
    break;
  case ESCAPE_LEFT_BRACE:
    buf[1] = '{';
    break;
  case ESCAPE_RIGHT_BRACE:
    buf[1] = '}';
    break;
  case ESCAPE_LEFT_QUOTE:
    buf[1] = '`';
    break;
  case ESCAPE_RIGHT_QUOTE:
    buf[1] = '\'';
    break;
  case ESCAPE_HYPHEN:
    buf[1] = '-';
    break;
  case ESCAPE_BANG:
    buf[1] = '!';
    break;
  case ESCAPE_c:
    buf[1] = 'c';
    break;
  case ESCAPE_e:
    buf[1] = 'e';
    break;
  case ESCAPE_E:
    buf[1] = 'E';
    break;
  case ESCAPE_PERCENT:
    buf[1] = '%';
    break;
  case ESCAPE_SPACE:
    buf[1] = ' ';
    break;
  case ESCAPE_TILDE:
    buf[1] = '~';
    break;
  case ESCAPE_COLON:
    buf[1] = ':';
    break;
  case PUSH_GROFF_MODE:
  case PUSH_COMP_MODE:
  case POP_GROFFCOMP_MODE:
    buf[0] = '\0';
    break;
  default:
    if (invalid_input_char(c))
      buf[0] = '\0';
    else
      buf[0] = c;
    break;
  }
  return buf;
}

const char *input_char_description(int c)
{
  switch (c) {
  case '\n':
    return "a newline character";
  case '\b':
    return "a backspace character";
  case '\001':
    return "a leader character";
  case '\t':
    return "a tab character";
  case ' ':
    return "a space character";
  case '\0':
    return "a node";
  }
  static char buf[sizeof("magic character code ") + 1 + INT_DIGITS];
  if (invalid_input_char(c)) {
    const char *s = asciify(c);
    if (*s) {
      buf[0] = '`';
      strcpy(buf + 1, s);
      strcat(buf, "'");
      return buf;
    }
    sprintf(buf, "magic character code %d", c);
    return buf;
  }
  if (csprint(c)) {
    buf[0] = '`';
    buf[1] = c;
    buf[2] = '\'';
    return buf;
  }
  sprintf(buf, "character code %d", c);
  return buf;
}

void tag()
{
  if (!tok.newline() && !tok.eof()) {
    string s;
    int c;
    for (;;) {
      c = get_copy(0);
      if (c == '"') {
        c = get_copy(0);
        break;
      }
      if (c != ' ' && c != '\t')
        break;
    }
    s = "x X ";
    for (; c != '\n' && c != EOF; c = get_copy(0))
      s += (char)c;
    s += '\n';
    curenv->add_node(new tag_node(s, 0));
  }
  tok.next();
}

void taga()
{
  if (!tok.newline() && !tok.eof()) {
    string s;
    int c;
    for (;;) {
      c = get_copy(0);
      if (c == '"') {
        c = get_copy(0);
        break;
      }
      if (c != ' ' && c != '\t')
        break;
    }
    s = "x X ";
    for (; c != '\n' && c != EOF; c = get_copy(0))
      s += (char)c;
    s += '\n';
    curenv->add_node(new tag_node(s, 1));
  }
  tok.next();
}

// .tm, .tm1, and .tmc

void do_terminal(int newline, int string_like)
{
  if (!tok.newline() && !tok.eof()) {
    int c;
    for (;;) {
      c = get_copy(0);
      if (string_like && c == '"') {
        c = get_copy(0);
        break;
      }
      if (c != ' ' && c != '\t')
        break;
    }
    for (; c != '\n' && c != EOF; c = get_copy(0))
      fputs(asciify(c), stderr);
  }
  if (newline)
    fputc('\n', stderr);
  fflush(stderr);
  tok.next();
}

void terminal()
{
  do_terminal(1, 0);
}

void terminal1()
{
  do_terminal(1, 1);
}

void terminal_continue()
{
  do_terminal(0, 1);
}

dictionary stream_dictionary(20);

void do_open(int append)
{
  symbol stream = get_name(1);
  if (!stream.is_null()) {
    symbol filename = get_long_name(1);
    if (!filename.is_null()) {
      errno = 0;
      FILE *fp = fopen(filename.contents(), append ? "a" : "w");
      if (!fp) {
        error("can't open `%1' for %2: %3",
              filename.contents(),
              append ? "appending" : "writing",
              strerror(errno));
        fp = (FILE *)stream_dictionary.remove(stream);
      }
      else
        fp = (FILE *)stream_dictionary.lookup(stream, fp);
      if (fp)
        fclose(fp);
    }
  }
  skip_line();
}

void open_request()
{
  if (!unsafe_flag) {
    error(".open request not allowed in safer mode");
    skip_line();
  }
  else
    do_open(0);
}

void opena_request()
{
  if (!unsafe_flag) {
    error(".opena request not allowed in safer mode");
    skip_line();
  }
  else
    do_open(1);
}

void close_request()
{
  symbol stream = get_name(1);
  if (!stream.is_null()) {
    FILE *fp = (FILE *)stream_dictionary.remove(stream);
    if (!fp)
      error("no stream named `%1'", stream.contents());
    else
      fclose(fp);
  }
  skip_line();
}

// .write and .writec

void do_write_request(int newline)
{
  symbol stream = get_name(1);
  if (stream.is_null()) {
    skip_line();
    return;
  }
  FILE *fp = (FILE *)stream_dictionary.lookup(stream);
  if (!fp) {
    error("no stream named `%1'", stream.contents());
    skip_line();
    return;
  }
  int c;
  while ((c = get_copy(0)) == ' ')
    ;
  if (c == '"')
    c = get_copy(0);
  for (; c != '\n' && c != EOF; c = get_copy(0))
    fputs(asciify(c), fp);
  if (newline)
    fputc('\n', fp);
  fflush(fp);
  tok.next();
}

void write_request()
{
  do_write_request(1);
}

void write_request_continue()
{
  do_write_request(0);
}

void write_macro_request()
{
  symbol stream = get_name(1);
  if (stream.is_null()) {
    skip_line();
    return;
  }
  FILE *fp = (FILE *)stream_dictionary.lookup(stream);
  if (!fp) {
    error("no stream named `%1'", stream.contents());
    skip_line();
    return;
  }
  symbol s = get_name(1);
  if (s.is_null()) {
    skip_line();
    return;
  }
  request_or_macro *p = lookup_request(s);
  macro *m = p->to_macro();
  if (!m)
    error("cannot write request");
  else {
    string_iterator iter(*m);
    for (;;) {
      int c = iter.get(0);
      if (c == EOF)
        break;
      fputs(asciify(c), fp);
    }
    fflush(fp);
  }
  skip_line();
}

void warnscale_request()
{
  if (has_arg()) {
    char c = tok.ch();
    if (c == 'u')
      warn_scale = 1.0;
    else if (c == 'i')
      warn_scale = (double)units_per_inch;
    else if (c == 'c')
      warn_scale = (double)units_per_inch / 2.54;
    else if (c == 'p')
      warn_scale = (double)units_per_inch / 72.0;
    else if (c == 'P')
      warn_scale = (double)units_per_inch / 6.0;
    else {
      warning(WARN_SCALE,
              "invalid scaling indicator `%1', using `i' instead", c);
      c = 'i';
    }
    warn_scaling_indicator = c;
  }
  skip_line();
}

void spreadwarn_request()
{
  hunits n;
  if (has_arg() && get_hunits(&n, 'm')) {
    if (n < 0)
      n = 0;
    hunits em = curenv->get_size();
    spread_limit = (double)n.to_units()
                   / (em.is_zero() ? hresolution : em.to_units());
  }
  else
    spread_limit = -spread_limit - 1;   // no arg toggles on/off without
                                        // changing value; we mirror at
                                        // -0.5 to make zero a valid value
  skip_line();
}

static void init_charset_table()
{
  char buf[16];
  strcpy(buf, "char");
  for (int i = 0; i < 256; i++) {
    strcpy(buf + 4, i_to_a(i));
    charset_table[i] = get_charinfo(symbol(buf));
    charset_table[i]->set_ascii_code(i);
    if (csalpha(i))
      charset_table[i]->set_hyphenation_code(cmlower(i));
  }
  charset_table['.']->set_flags(charinfo::ENDS_SENTENCE);
  charset_table['?']->set_flags(charinfo::ENDS_SENTENCE);
  charset_table['!']->set_flags(charinfo::ENDS_SENTENCE);
  charset_table['-']->set_flags(charinfo::BREAK_AFTER);
  charset_table['"']->set_flags(charinfo::TRANSPARENT);
  charset_table['\'']->set_flags(charinfo::TRANSPARENT);
  charset_table[')']->set_flags(charinfo::TRANSPARENT);
  charset_table[']']->set_flags(charinfo::TRANSPARENT);
  charset_table['*']->set_flags(charinfo::TRANSPARENT);
  get_charinfo(symbol("dg"))->set_flags(charinfo::TRANSPARENT);
  get_charinfo(symbol("rq"))->set_flags(charinfo::TRANSPARENT);
  get_charinfo(symbol("em"))->set_flags(charinfo::BREAK_AFTER);
  get_charinfo(symbol("hy"))->set_flags(charinfo::BREAK_AFTER);
  get_charinfo(symbol("ul"))->set_flags(charinfo::OVERLAPS_HORIZONTALLY);
  get_charinfo(symbol("rn"))->set_flags(charinfo::OVERLAPS_HORIZONTALLY);
  get_charinfo(symbol("radicalex"))->set_flags(charinfo::OVERLAPS_HORIZONTALLY);
  get_charinfo(symbol("sqrtex"))->set_flags(charinfo::OVERLAPS_HORIZONTALLY);
  get_charinfo(symbol("ru"))->set_flags(charinfo::OVERLAPS_HORIZONTALLY);
  get_charinfo(symbol("br"))->set_flags(charinfo::OVERLAPS_VERTICALLY);
  page_character = charset_table['%'];
}

static void init_hpf_code_table()
{
  for (int i = 0; i < 256; i++)
    hpf_code_table[i] = i;
}

static void do_translate(int translate_transparent, int translate_input)
{
  tok.skip();
  while (!tok.newline() && !tok.eof()) {
    if (tok.space()) {
      // This is a really bizarre troff feature.
      tok.next();
      translate_space_to_dummy = tok.dummy();
      if (tok.newline() || tok.eof())
        break;
      tok.next();
      continue;
    }
    charinfo *ci1 = tok.get_char(1);
    if (ci1 == 0)
      break;
    tok.next();
    if (tok.newline() || tok.eof()) {
      ci1->set_special_translation(charinfo::TRANSLATE_SPACE,
                                   translate_transparent);
      break;
    }
    if (tok.space())
      ci1->set_special_translation(charinfo::TRANSLATE_SPACE,
                                   translate_transparent);
    else if (tok.stretchable_space())
      ci1->set_special_translation(charinfo::TRANSLATE_STRETCHABLE_SPACE,
                                   translate_transparent);
    else if (tok.dummy())
      ci1->set_special_translation(charinfo::TRANSLATE_DUMMY,
                                   translate_transparent);
    else if (tok.hyphen_indicator())
      ci1->set_special_translation(charinfo::TRANSLATE_HYPHEN_INDICATOR,
                                   translate_transparent);
    else {
      charinfo *ci2 = tok.get_char(1);
      if (ci2 == 0)
        break;
      if (ci1 == ci2)
        ci1->set_translation(0, translate_transparent, translate_input);
      else
        ci1->set_translation(ci2, translate_transparent, translate_input);
    }
    tok.next();
  }
  skip_line();
}

void translate()
{
  do_translate(1, 0);
}

void translate_no_transparent()
{
  do_translate(0, 0);
}

void translate_input()
{
  do_translate(1, 1);
}

void char_flags()
{
  int flags;
  if (get_integer(&flags))
    while (has_arg()) {
      charinfo *ci = tok.get_char(1);
      if (ci) {
        charinfo *tem = ci->get_translation();
        if (tem)
          ci = tem;
        ci->set_flags(flags);
      }
      tok.next();
    }
  skip_line();
}

void hyphenation_code()
{
  tok.skip();
  while (!tok.newline() && !tok.eof()) {
    charinfo *ci = tok.get_char(1);
    if (ci == 0)
      break;
    tok.next();
    tok.skip();
    unsigned char c = tok.ch();
    if (c == 0) {
      error("hyphenation code must be ordinary character");
      break;
    }
    if (csdigit(c)) {
      error("hyphenation code cannot be digit");
      break;
    }
    ci->set_hyphenation_code(c);
    if (ci->get_translation()
        && ci->get_translation()->get_translation_input())
      ci->get_translation()->set_hyphenation_code(c);
    tok.next();
    tok.skip();
  }
  skip_line();
}

void hyphenation_patterns_file_code()
{
  tok.skip();
  while (!tok.newline() && !tok.eof()) {
    int n1, n2;
    if (get_integer(&n1) && (0 <= n1 && n1 <= 255)) {
      if (!has_arg()) {
        error("missing output hyphenation code");
        break;
      }
      if (get_integer(&n2) && (0 <= n2 && n2 <= 255)) {
        hpf_code_table[n1] = n2;
        tok.skip();
      }
      else {
        error("output hyphenation code must be integer in the range 0..255");
        break;
      }
    }
    else {
      error("input hyphenation code must be integer in the range 0..255");
      break;
    }
  }
  skip_line();
}

charinfo *token::get_char(int required)
{
  if (type == TOKEN_CHAR)
    return charset_table[c];
  if (type == TOKEN_SPECIAL)
    return get_charinfo(nm);
  if (type == TOKEN_NUMBERED_CHAR)
    return get_charinfo_by_number(val);
  if (type == TOKEN_ESCAPE) {
    if (escape_char != 0)
      return charset_table[escape_char];
    else {
      error("`\\e' used while no current escape character");
      return 0;
    }
  }
  if (required) {
    if (type == TOKEN_EOF || type == TOKEN_NEWLINE)
      warning(WARN_MISSING, "missing normal or special character");
    else
      error("normal or special character expected (got %1)", description());
  }
  return 0;
}

charinfo *get_optional_char()
{
  while (tok.space())
    tok.next();
  charinfo *ci = tok.get_char();
  if (!ci)
    check_missing_character();
  else
    tok.next();
  return ci;
}

void check_missing_character()
{
  if (!tok.newline() && !tok.eof() && !tok.right_brace() && !tok.tab())
    error("normal or special character expected (got %1): "
          "treated as missing",
          tok.description());
}

// this is for \Z

int token::add_to_node_list(node **pp)
{
  hunits w;
  int s;
  node *n = 0;
  switch (type) {
  case TOKEN_CHAR:
    *pp = (*pp)->add_char(charset_table[c], curenv, &w, &s);
    break;
  case TOKEN_DUMMY:
    n = new dummy_node;
    break;
  case TOKEN_ESCAPE:
    if (escape_char != 0)
      *pp = (*pp)->add_char(charset_table[escape_char], curenv, &w, &s);
    break;
  case TOKEN_HYPHEN_INDICATOR:
    *pp = (*pp)->add_discretionary_hyphen();
    break;
  case TOKEN_ITALIC_CORRECTION:
    *pp = (*pp)->add_italic_correction(&w);
    break;
  case TOKEN_LEFT_BRACE:
    break;
  case TOKEN_MARK_INPUT:
    set_number_reg(nm, curenv->get_input_line_position().to_units());
    break;
  case TOKEN_NODE:
    n = nd;
    nd = 0;
    break;
  case TOKEN_NUMBERED_CHAR:
    *pp = (*pp)->add_char(get_charinfo_by_number(val), curenv, &w, &s);
    break;
  case TOKEN_RIGHT_BRACE:
    break;
  case TOKEN_SPACE:
    n = new hmotion_node(curenv->get_space_width(),
                         curenv->get_fill_color());
    break;
  case TOKEN_SPECIAL:
    *pp = (*pp)->add_char(get_charinfo(nm), curenv, &w, &s);
    break;
  case TOKEN_STRETCHABLE_SPACE:
    n = new unbreakable_space_node(curenv->get_space_width(),
                                   curenv->get_fill_color());
    break;
  case TOKEN_UNSTRETCHABLE_SPACE:
    n = new space_char_hmotion_node(curenv->get_space_width(),
                                    curenv->get_fill_color());
    break;
  case TOKEN_TRANSPARENT_DUMMY:
    n = new transparent_dummy_node;
    break;
  case TOKEN_ZERO_WIDTH_BREAK:
    n = new space_node(H0, curenv->get_fill_color());
    n->freeze_space();
    n->is_escape_colon();
    break;
  default:
    return 0;
  }
  if (n) {
    n->next = *pp;
    *pp = n;
  }
  return 1;
}

void token::process()
{
  if (possibly_handle_first_page_transition())
    return;
  switch (type) {
  case TOKEN_BACKSPACE:
    curenv->add_node(new hmotion_node(-curenv->get_space_width(),
                                      curenv->get_fill_color()));
    break;
  case TOKEN_CHAR:
    curenv->add_char(charset_table[c]);
    break;
  case TOKEN_DUMMY:
    curenv->add_node(new dummy_node);
    break;
  case TOKEN_EMPTY:
    assert(0);
    break;
  case TOKEN_EOF:
    assert(0);
    break;
  case TOKEN_ESCAPE:
    if (escape_char != 0)
      curenv->add_char(charset_table[escape_char]);
    break;
  case TOKEN_BEGIN_TRAP:
  case TOKEN_END_TRAP:
  case TOKEN_PAGE_EJECTOR:
    // these are all handled in process_input_stack()
    break;
  case TOKEN_HYPHEN_INDICATOR:
    curenv->add_hyphen_indicator();
    break;
  case TOKEN_INTERRUPT:
    curenv->interrupt();
    break;
  case TOKEN_ITALIC_CORRECTION:
    curenv->add_italic_correction();
    break;
  case TOKEN_LEADER:
    curenv->handle_tab(1);
    break;
  case TOKEN_LEFT_BRACE:
    break;
  case TOKEN_MARK_INPUT:
    set_number_reg(nm, curenv->get_input_line_position().to_units());
    break;
  case TOKEN_NEWLINE:
    curenv->newline();
    break;
  case TOKEN_NODE:
    curenv->add_node(nd);
    nd = 0;
    break;
  case TOKEN_NUMBERED_CHAR:
    curenv->add_char(get_charinfo_by_number(val));
    break;
  case TOKEN_REQUEST:
    // handled in process_input_stack()
    break;
  case TOKEN_RIGHT_BRACE:
    break;
  case TOKEN_SPACE:
    curenv->space();
    break;
  case TOKEN_SPECIAL:
    curenv->add_char(get_charinfo(nm));
    break;
  case TOKEN_SPREAD:
    curenv->spread();
    break;
  case TOKEN_STRETCHABLE_SPACE:
    curenv->add_node(new unbreakable_space_node(curenv->get_space_width(),
                                                curenv->get_fill_color()));
    break;
  case TOKEN_UNSTRETCHABLE_SPACE:
    curenv->add_node(new space_char_hmotion_node(curenv->get_space_width(),
                                                 curenv->get_fill_color()));
    break;
  case TOKEN_TAB:
    curenv->handle_tab(0);
    break;
  case TOKEN_TRANSPARENT:
    break;
  case TOKEN_TRANSPARENT_DUMMY:
    curenv->add_node(new transparent_dummy_node);
    break;
  case TOKEN_ZERO_WIDTH_BREAK:
    {
      node *tmp = new space_node(H0, curenv->get_fill_color());
      tmp->freeze_space();
      tmp->is_escape_colon();
      curenv->add_node(tmp);
      break;
    }
  default:
    assert(0);
  }
}

class nargs_reg : public reg {
public:
  const char *get_string();
};

const char *nargs_reg::get_string()
{
  return i_to_a(input_stack::nargs());
}

class lineno_reg : public reg {
public:
  const char *get_string();
};

const char *lineno_reg::get_string()
{
  int line;
  const char *file;
  if (!input_stack::get_location(0, &file, &line))
    line = 0;
  return i_to_a(line);
}

class writable_lineno_reg : public general_reg {
public:
  writable_lineno_reg();
  void set_value(units);
  int get_value(units *);
};

writable_lineno_reg::writable_lineno_reg()
{
}

int writable_lineno_reg::get_value(units *res)
{
  int line;
  const char *file;
  if (!input_stack::get_location(0, &file, &line))
    return 0;
  *res = line;
  return 1;
}

void writable_lineno_reg::set_value(units n)
{
  input_stack::set_location(0, n);
}

class filename_reg : public reg {
public:
  const char *get_string();
};

const char *filename_reg::get_string()
{
  int line;
  const char *file;
  if (input_stack::get_location(0, &file, &line))
    return file;
  else
    return 0;
}

class break_flag_reg : public reg {
public:
  const char *get_string();
};

const char *break_flag_reg::get_string()
{
  return i_to_a(input_stack::get_break_flag());
}

class constant_reg : public reg {
  const char *s;
public:
  constant_reg(const char *);
  const char *get_string();
};

constant_reg::constant_reg(const char *p) : s(p)
{
}

const char *constant_reg::get_string()
{
  return s;
}

constant_int_reg::constant_int_reg(int *q) : p(q)
{
}

const char *constant_int_reg::get_string()
{
  return i_to_a(*p);
}

void abort_request()
{
  int c;
  if (tok.eof())
    c = EOF;
  else if (tok.newline())
    c = '\n';
  else {
    while ((c = get_copy(0)) == ' ')
      ;
  }
  if (c == EOF || c == '\n')
    fputs("User Abort.", stderr);
  else {
    for (; c != '\n' && c != EOF; c = get_copy(0))
      fputs(asciify(c), stderr);
  }
  fputc('\n', stderr);
  cleanup_and_exit(1);
}

char *read_string()
{
  int len = 256;
  char *s = new char[len];
  int c;
  while ((c = get_copy(0)) == ' ')
    ;
  int i = 0;
  while (c != '\n' && c != EOF) {
    if (!invalid_input_char(c)) {
      if (i + 2 > len) {
        char *tem = s;
        s = new char[len*2];
        memcpy(s, tem, len);
        len *= 2;
        a_delete tem;
      }
      s[i++] = c;
    }
    c = get_copy(0);
  }
  s[i] = '\0';
  tok.next();
  if (i == 0) {
    a_delete s;
    return 0;
  }
  return s;
}

void pipe_output()
{
  if (!unsafe_flag) {
    error(".pi request not allowed in safer mode");
    skip_line();
  }
  else {
#ifdef POPEN_MISSING
    error("pipes not available on this system");
    skip_line();
#else /* not POPEN_MISSING */
    if (the_output) {
      error("can't pipe: output already started");
      skip_line();
    }
    else {
      char *pc;
      if ((pc = read_string()) == 0)
        error("can't pipe to empty command");
      if (pipe_command) {
        char *s = new char[strlen(pipe_command) + strlen(pc) + 1 + 1];
        strcpy(s, pipe_command);
        strcat(s, "|");
        strcat(s, pc);
        a_delete pipe_command;
        a_delete pc;
        pipe_command = s;
      }
      else
        pipe_command = pc;
    }
#endif /* not POPEN_MISSING */
  }
}

static int system_status;

void system_request()
{
  if (!unsafe_flag) {
    error(".sy request not allowed in safer mode");
    skip_line();
  }
  else {
    char *command = read_string();
    if (!command)
      error("empty command");
    else {
      system_status = system(command);
      a_delete command;
    }
  }
}

void copy_file()
{
  if (curdiv == topdiv && topdiv->before_first_page) {
    handle_initial_request(COPY_FILE_REQUEST);
    return;
  }
  symbol filename = get_long_name(1);
  while (!tok.newline() && !tok.eof())
    tok.next();
  if (break_flag)
    curenv->do_break();
  if (!filename.is_null())
    curdiv->copy_file(filename.contents());
  tok.next();
}

#ifdef COLUMN

void vjustify()
{
  if (curdiv == topdiv && topdiv->before_first_page) {
    handle_initial_request(VJUSTIFY_REQUEST);
    return;
  }
  symbol type = get_long_name(1);
  if (!type.is_null())
    curdiv->vjustify(type);
  skip_line();
}

#endif /* COLUMN */

void transparent_file()
{
  if (curdiv == topdiv && topdiv->before_first_page) {
    handle_initial_request(TRANSPARENT_FILE_REQUEST);
    return;
  }
  symbol filename = get_long_name(1);
  while (!tok.newline() && !tok.eof())
    tok.next();
  if (break_flag)
    curenv->do_break();
  if (!filename.is_null()) {
    file_case *fcp = include_search_path
        .open_file_cautious(filename.contents());
    if (fcp == NULL)
      error("can't open `%1': %2", filename.contents(), strerror(errno));
    else {
      int bol = 1;
      for (;;) {
        int c = fcp->get_c();
        if (c == EOF)
          break;
        if (invalid_input_char(c))
          warning(WARN_INPUT, "invalid input character code %1", int(c));
        else {
          curdiv->transparent_output(c);
          bol = c == '\n';
        }
      }
      if (!bol)
        curdiv->transparent_output('\n');
      delete fcp;
    }
  }
  tok.next();
}

class page_range {
  int first;
  int last;
public:
  page_range *next;
  page_range(int, int, page_range *);
  int contains(int n);
};

page_range::page_range(int i, int j, page_range *p)
: first(i), last(j), next(p)
{
}

int page_range::contains(int n)
{
  return n >= first && (last <= 0 || n <= last);
}

page_range *output_page_list = 0;

int in_output_page_list(int n)
{
  if (!output_page_list)
    return 1;
  for (page_range *p = output_page_list; p; p = p->next)
    if (p->contains(n))
      return 1;
  return 0;
}

static void parse_output_page_list(char *p)
{
  for (;;) {
    int i;
    if (*p == '-')
      i = 1;
    else if (csdigit(*p)) {
      i = 0;
      do
        i = i*10 + *p++ - '0';
      while (csdigit(*p));
    }
    else
      break;
    int j;
    if (*p == '-') {
      p++;
      j = 0;
      if (csdigit(*p)) {
        do
          j = j*10 + *p++ - '0';
        while (csdigit(*p));
      }
    }
    else
      j = i;
    if (j == 0)
      last_page_number = -1;
    else if (last_page_number >= 0 && j > last_page_number)
      last_page_number = j;
    output_page_list = new page_range(i, j, output_page_list);
    if (*p != ',')
      break;
    ++p;
  }
  if (*p != '\0') {
    error("bad output page list");
    output_page_list = 0;
  }
}

static file_case *open_mac_file(const char *mac)
{
  // Try first FOOBAR.tmac, then tmac.FOOBAR
  char *s = new char[strlen(mac) + strlen(MACRO_POSTFIX) +1];
  strcpy(s, mac);
  strcat(s, MACRO_POSTFIX);

  file_case *fcp;
  if ((fcp = mac_path->open_file(s, fcp->fc_take_path)) == NULL) {
    s = new char[strlen(mac) + strlen(MACRO_PREFIX) +1];
    strcpy(s, MACRO_PREFIX);
    strcat(s, mac);
    fcp = mac_path->open_file(s, fcp->fc_take_path);
  }
  return fcp;
}

static void process_macro_file(const char *mac)
{
  file_case *fcp = open_mac_file(mac);
  if (fcp == NULL)
    fatal("can't find macro file %1", mac);
  const char *s = symbol(fcp->path()).contents();
  input_stack::push(new file_iterator(fcp, s));
  tok.next();
  process_input_stack();
}

static void process_startup_file(const char *filename)
{
  search_path *orig_mac_path = mac_path;
  mac_path = &config_macro_path;
  file_case *fcp;
  if ((fcp = mac_path->open_file(filename)) != NULL) {
    input_stack::push(new file_iterator(fcp, symbol(fcp->path()).contents()));
    tok.next();
    process_input_stack();
  }
  mac_path = orig_mac_path;
}

void macro_source()
{
  symbol nm = get_long_name(1);
  if (nm.is_null())
    skip_line();
  else {
    while (!tok.newline() && !tok.eof())
      tok.next();
    // .mso doesn't (and cannot) go through open_mac_file, so we
    // need to do it here manually: If we have tmac.FOOBAR, try
    // FOOBAR.tmac and vice versa
    file_case *fcp;
    if ((fcp = mac_path->open_file(nm.contents())) == NULL) {
      const char *fn = nm.contents();

      if (strncasecmp(fn, MACRO_PREFIX, sizeof(MACRO_PREFIX) - 1) == 0) {
        char *s = new char[strlen(fn) + sizeof(MACRO_POSTFIX)];
        strcpy(s, fn + sizeof(MACRO_PREFIX) - 1);
        strcat(s, MACRO_POSTFIX);
        fcp = mac_path->open_file(s, fcp->fc_take_path);
      }

      if (fcp == NULL) {
        if (strncasecmp(fn + strlen(fn) - sizeof(MACRO_POSTFIX) + 1,
            MACRO_POSTFIX, sizeof(MACRO_POSTFIX) - 1) == 0) {
          char *s = new char[strlen(fn) + sizeof(MACRO_PREFIX)];
          strcpy(s, MACRO_PREFIX);
          strncat(s, fn, strlen(fn) - sizeof(MACRO_POSTFIX) + 1);
          fcp = mac_path->open_file(s, fcp->fc_take_path);
        }
      }
    }

    if (fcp != NULL)
      input_stack::push(new file_iterator(fcp, symbol(fcp->path()).contents()));
    else
      warning(WARN_FILE, "can't find macro file `%1'", nm.contents());
    tok.next();
  }
}

static void process_input_file(const char *name)
{
  file_case *fcp;
  if ((fcp = include_search_path.open_file_cautious(name)) == NULL) {
    assert(strcmp(name, "-"));
    fatal("can't open `%1': %2", name, strerror(errno));
   }
  input_stack::push(new file_iterator(fcp, name));
  tok.next();
  process_input_stack();
}

// make sure the_input is empty before calling this

static int evaluate_expression(const char *expr, units *res)
{
  input_stack::push(make_temp_iterator(expr));
  tok.next();
  int success = get_number(res, 'u');
  while (input_stack::get(0) != EOF)
    ;
  return success;
}

static void do_register_assignment(const char *s)
{
  const char *p = strchr(s, '=');
  if (!p) {
    char buf[2];
    buf[0] = s[0];
    buf[1] = 0;
    units n;
    if (evaluate_expression(s + 1, &n))
      set_number_reg(buf, n);
  }
  else {
    char *buf = new char[p - s + 1];
    memcpy(buf, s, p - s);
    buf[p - s] = 0;
    units n;
    if (evaluate_expression(p + 1, &n))
      set_number_reg(buf, n);
    a_delete buf;
  }
}

static void set_string(const char *name, const char *value)
{
  macro *m = new macro;
  for (const char *p = value; *p; p++)
    if (!invalid_input_char((unsigned char)*p))
      m->append(*p);
  request_dictionary.define(name, m);
}

static void do_string_assignment(const char *s)
{
  const char *p = strchr(s, '=');
  if (!p) {
    char buf[2];
    buf[0] = s[0];
    buf[1] = 0;
    set_string(buf, s + 1);
  }
  else {
    char *buf = new char[p - s + 1];
    memcpy(buf, s, p - s);
    buf[p - s] = 0;
    set_string(buf, p + 1);
    a_delete buf;
  }
}

struct string_list {
  const char *s;
  string_list *next;
  string_list(const char *ss) : s(ss), next(0) {}
};

#if 0
static void prepend_string(const char *s, string_list **p)
{
  string_list *l = new string_list(s);
  l->next = *p;
  *p = l;
}
#endif

static void add_string(const char *s, string_list **p)
{
  while (*p)
    p = &((*p)->next);
  *p = new string_list(s);
}

void usage(FILE *stream, const char *prog)
{
  fprintf(stream,
"usage: %s -abcivzCERU -wname -Wname -dcs -ffam -mname -nnum -olist\n"
"       -rcn -Tname -Fdir -Idir -Mdir [files...]\n",
          prog);
}

int main(int argc, char **argv)
{
  program_name = argv[0];
  static char stderr_buf[BUFSIZ];
  setbuf(stderr, stderr_buf);
  int c;
  string_list *macros = 0;
  string_list *register_assignments = 0;
  string_list *string_assignments = 0;
  int iflag = 0;
  int tflag = 0;
  int fflag = 0;
  int nflag = 0;
  int no_rc = 0;                // don't process troffrc and troffrc-end
  int next_page_number = 0;     // pacify compiler
  opterr = 0;
  hresolution = vresolution = 1;
  // restore $PATH if called from groff
  char* groff_path = getenv("GROFF_PATH__");
  if (groff_path) {
    string e = "PATH";
    e += '=';
    if (*groff_path)
      e += groff_path;
    e += '\0';
    if (putenv(strsave(e.contents())))
      fatal("putenv failed");
  }
  static const struct option long_options[] = {
    { "help", no_argument, 0, CHAR_MAX + 1 },
    { "version", no_argument, 0, 'v' },
    { 0, 0, 0, 0 }
  };
#if defined(DEBUGGING)
#define DEBUG_OPTION "D"
#endif
  while ((c = getopt_long(argc, argv,
                          "abciI:vw:W:zCEf:m:n:o:r:d:F:M:T:tqs:RU"
                          DEBUG_OPTION, long_options, 0))
         != EOF)
    switch(c) {
    case 'v':
      {
        printf("GNU troff (groff) version %s\n", Version_string);
        exit(0);
        break;
      }
    case 'I':
      // Search path for .psbb files
      // and most other non-system input files.
      include_search_path.command_line_dir(optarg);
      break;
    case 'T':
      device = optarg;
      tflag = 1;
      is_html = (strcmp(device, "html") == 0);
      break;
    case 'C':
      compatible_flag = 1;
      // fall through
    case 'c':
      color_flag = 0;
      break;
    case 'M':
      macro_path.command_line_dir(optarg);
      safer_macro_path.command_line_dir(optarg);
      config_macro_path.command_line_dir(optarg);
      break;
    case 'F':
      font::command_line_font_dir(optarg);
      break;
    case 'm':
      add_string(optarg, &macros);
      break;
    case 'E':
      inhibit_errors = 1;
      break;
    case 'R':
      no_rc = 1;
      break;
    case 'w':
      enable_warning(optarg);
      break;
    case 'W':
      disable_warning(optarg);
      break;
    case 'i':
      iflag = 1;
      break;
    case 'b':
      backtrace_flag = 1;
      break;
    case 'a':
      ascii_output_flag = 1;
      break;
    case 'z':
      suppress_output_flag = 1;
      break;
    case 'n':
      if (sscanf(optarg, "%d", &next_page_number) == 1)
        nflag++;
      else
        error("bad page number");
      break;
    case 'o':
      parse_output_page_list(optarg);
      break;
    case 'd':
      if (*optarg == '\0')
        error("`-d' requires non-empty argument");
      else
        add_string(optarg, &string_assignments);
      break;
    case 'r':
      if (*optarg == '\0')
        error("`-r' requires non-empty argument");
      else
        add_string(optarg, &register_assignments);
      break;
    case 'f':
      default_family = symbol(optarg);
      fflag = 1;
      break;
    case 'q':
    case 's':
    case 't':
      // silently ignore these
      break;
    case 'U':
      unsafe_flag = 1;  // unsafe behaviour
      break;
#if defined(DEBUGGING)
    case 'D':
      debug_state = 1;
      break;
#endif
    case CHAR_MAX + 1: // --help
      usage(stdout, argv[0]);
      exit(0);
      break;
    case '?':
      usage(stderr, argv[0]);
      exit(1);
      break;            // never reached
    default:
      assert(0);
    }
  if (unsafe_flag)
    mac_path = &macro_path;
  set_string(".T", device);
  init_charset_table();
  init_hpf_code_table();
  if (!font::load_desc())
    fatal("sorry, I can't continue");
  units_per_inch = font::res;
  hresolution = font::hor;
  vresolution = font::vert;
  sizescale = font::sizescale;
  tcommand_flag = font::tcommand;
  warn_scale = (double)units_per_inch;
  warn_scaling_indicator = 'i';
  if (!fflag && font::family != 0 && *font::family != '\0')
    default_family = symbol(font::family);
  font_size::init_size_table(font::sizes);
  int i;
  int j = 1;
  if (font::style_table) {
    for (i = 0; font::style_table[i]; i++)
      mount_style(j++, symbol(font::style_table[i]));
  }
  for (i = 0; font::font_name_table[i]; i++, j++)
    // In the DESC file a font name of 0 (zero) means leave this
    // position empty.
    if (strcmp(font::font_name_table[i], "0") != 0)
      mount_font(j, symbol(font::font_name_table[i]));
  curdiv = topdiv = new top_level_diversion;
  if (nflag)
    topdiv->set_next_page_number(next_page_number);
  init_input_requests();
  init_env_requests();
  init_div_requests();
#ifdef COLUMN
  init_column_requests();
#endif /* COLUMN */
  init_node_requests();
  number_reg_dictionary.define(".T", new constant_reg(tflag ? "1" : "0"));
  init_registers();
  init_reg_requests();
  init_hyphen_requests();
  init_environments();
  while (string_assignments) {
    do_string_assignment(string_assignments->s);
    string_list *tem = string_assignments;
    string_assignments = string_assignments->next;
    delete tem;
  }
  while (register_assignments) {
    do_register_assignment(register_assignments->s);
    string_list *tem = register_assignments;
    register_assignments = register_assignments->next;
    delete tem;
  }
  if (!no_rc)
    process_startup_file(INITIAL_STARTUP_FILE);
  while (macros) {
    process_macro_file(macros->s);
    string_list *tem = macros;
    macros = macros->next;
    delete tem;
  }
  if (!no_rc)
    process_startup_file(FINAL_STARTUP_FILE);
  for (i = optind; i < argc; i++)
    process_input_file(argv[i]);
  if (optind >= argc || iflag)
    process_input_file("-");
  exit_troff();
  return 0;                     // not reached
}

void warn_request()
{
  int n;
  if (has_arg() && get_integer(&n)) {
    if (n & ~WARN_TOTAL) {
      warning(WARN_RANGE, "warning mask must be between 0 and %1", WARN_TOTAL);
      n &= WARN_TOTAL;
    }
    warning_mask = n;
  }
  else
    warning_mask = WARN_TOTAL;
  skip_line();
}

static void init_registers()
{
#ifdef LONG_FOR_TIME_T
  long
#else /* not LONG_FOR_TIME_T */
  time_t
#endif /* not LONG_FOR_TIME_T */
    t = time(0);
  // Use struct here to work around misfeature in old versions of g++.
  struct tm *tt = localtime(&t);
  set_number_reg("seconds", int(tt->tm_sec));
  set_number_reg("minutes", int(tt->tm_min));
  set_number_reg("hours", int(tt->tm_hour));
  set_number_reg("dw", int(tt->tm_wday + 1));
  set_number_reg("dy", int(tt->tm_mday));
  set_number_reg("mo", int(tt->tm_mon + 1));
  set_number_reg("year", int(1900 + tt->tm_year));
  set_number_reg("yr", int(tt->tm_year));
  set_number_reg("$$", getpid());
  number_reg_dictionary.define(".A",
                               new constant_reg(ascii_output_flag
                                                ? "1"
                                                : "0"));
}

/*
 *  registers associated with \O
 */

static int output_reg_minx_contents = -1;
static int output_reg_miny_contents = -1;
static int output_reg_maxx_contents = -1;
static int output_reg_maxy_contents = -1;

void check_output_limits(int x, int y)
{
  if ((output_reg_minx_contents == -1) || (x < output_reg_minx_contents))
    output_reg_minx_contents = x;
  if (x > output_reg_maxx_contents)
    output_reg_maxx_contents = x;
  if ((output_reg_miny_contents == -1) || (y < output_reg_miny_contents))
    output_reg_miny_contents = y;
  if (y > output_reg_maxy_contents)
    output_reg_maxy_contents = y;
}

void reset_output_registers()
{
  output_reg_minx_contents = -1;
  output_reg_miny_contents = -1;
  output_reg_maxx_contents = -1;
  output_reg_maxy_contents = -1;
}

void get_output_registers(int *minx, int *miny, int *maxx, int *maxy)
{
  *minx = output_reg_minx_contents;
  *miny = output_reg_miny_contents;
  *maxx = output_reg_maxx_contents;
  *maxy = output_reg_maxy_contents;
}

void init_input_requests()
{
  init_request("ab", abort_request);
  init_request("als", alias_macro);
  init_request("am", append_macro);
  init_request("am1", append_nocomp_macro);
  init_request("ami", append_indirect_macro);
  init_request("ami1", append_indirect_nocomp_macro);
  init_request("as", append_string);
  init_request("as1", append_nocomp_string);
  init_request("asciify", asciify_macro);
  init_request("backtrace", backtrace_request);
  init_request("blm", blank_line_macro);
  init_request("break", while_break_request);
  init_request("cf", copy_file);
  init_request("cflags", char_flags);
  init_request("char", define_character);
  init_request("chop", chop_macro);
  init_request("close", close_request);
  init_request("color", activate_color);
  init_request("composite", composite_request);
  init_request("continue", while_continue_request);
  init_request("cp", compatible);
  init_request("de", define_macro);
  init_request("de1", define_nocomp_macro);
  init_request("defcolor", define_color);
  init_request("dei", define_indirect_macro);
  init_request("dei1", define_indirect_nocomp_macro);
  init_request("device", device_request);
  init_request("devicem", device_macro_request);
  init_request("do", do_request);
  init_request("ds", define_string);
  init_request("ds1", define_nocomp_string);
  init_request("ec", set_escape_char);
  init_request("ecr", restore_escape_char);
  init_request("ecs", save_escape_char);
  init_request("el", else_request);
  init_request("em", end_macro);
  init_request("eo", escape_off);
  init_request("ex", exit_request);
  init_request("fchar", define_fallback_character);
#ifdef WIDOW_CONTROL
  init_request("fpl", flush_pending_lines);
#endif /* WIDOW_CONTROL */
  init_request("hcode", hyphenation_code);
  init_request("hpfcode", hyphenation_patterns_file_code);
  init_request("ie", if_else_request);
  init_request("if", if_request);
  init_request("ig", ignore);
  init_request("length", length_request);
  init_request("lf", line_file);
  init_request("mso", macro_source);
  init_request("nop", nop_request);
  init_request("nroff", nroff_request);
  init_request("nx", next_file);
  init_request("open", open_request);
  init_request("opena", opena_request);
  init_request("output", output_request);
  init_request("pc", set_page_character);
  init_request("pi", pipe_output);
  init_request("pm", print_macros);
  init_request("psbb", ps_bbox_request);
#ifndef POPEN_MISSING
  init_request("pso", pipe_source);
#endif /* not POPEN_MISSING */
  init_request("rchar", remove_character);
  init_request("rd", read_request);
  init_request("return", return_macro_request);
  init_request("rm", remove_macro);
  init_request("rn", rename_macro);
  init_request("schar", define_special_character);
  init_request("shift", shift);
  init_request("so", source);
  init_request("spreadwarn", spreadwarn_request);
  init_request("substring", substring_request);
  init_request("sy", system_request);
  init_request("tag", tag);
  init_request("taga", taga);
  init_request("tm", terminal);
  init_request("tm1", terminal1);
  init_request("tmc", terminal_continue);
  init_request("tr", translate);
  init_request("trf", transparent_file);
  init_request("trin", translate_input);
  init_request("trnt", translate_no_transparent);
  init_request("troff", troff_request);
  init_request("unformat", unformat_macro);
#ifdef COLUMN
  init_request("vj", vjustify);
#endif /* COLUMN */
  init_request("warn", warn_request);
  init_request("warnscale", warnscale_request);
  init_request("while", while_request);
  init_request("write", write_request);
  init_request("writec", write_request_continue);
  init_request("writem", write_macro_request);
  number_reg_dictionary.define(".$", new nargs_reg);
  number_reg_dictionary.define(".br", new break_flag_reg);
  number_reg_dictionary.define(".C", new constant_int_reg(&compatible_flag));
  number_reg_dictionary.define(".O", new variable_reg(&begin_level));
  number_reg_dictionary.define(".c", new lineno_reg);
  number_reg_dictionary.define(".color", new constant_int_reg(&color_flag));
  number_reg_dictionary.define(".F", new filename_reg);
  number_reg_dictionary.define(".g", new constant_reg("1"));
  number_reg_dictionary.define(".H", new constant_int_reg(&hresolution));
  number_reg_dictionary.define(".R", new constant_reg("10000"));
  number_reg_dictionary.define(".U", new constant_int_reg(&unsafe_flag));
  number_reg_dictionary.define(".V", new constant_int_reg(&vresolution));
  number_reg_dictionary.define(".warn", new constant_int_reg(&warning_mask));
  extern const char *major_version;
  number_reg_dictionary.define(".x", new constant_reg(major_version));
  extern const char *revision;
  number_reg_dictionary.define(".Y", new constant_reg(revision));
  extern const char *minor_version;
  number_reg_dictionary.define(".y", new constant_reg(minor_version));
  number_reg_dictionary.define("c.", new writable_lineno_reg);
  number_reg_dictionary.define("llx", new variable_reg(&llx_reg_contents));
  number_reg_dictionary.define("lly", new variable_reg(&lly_reg_contents));
  number_reg_dictionary.define("opmaxx",
                               new variable_reg(&output_reg_maxx_contents));
  number_reg_dictionary.define("opmaxy",
                               new variable_reg(&output_reg_maxy_contents));
  number_reg_dictionary.define("opminx",
                               new variable_reg(&output_reg_minx_contents));
  number_reg_dictionary.define("opminy",
                               new variable_reg(&output_reg_miny_contents));
  number_reg_dictionary.define("slimit",
                               new variable_reg(&input_stack::limit));
  number_reg_dictionary.define("systat", new variable_reg(&system_status));
  number_reg_dictionary.define("urx", new variable_reg(&urx_reg_contents));
  number_reg_dictionary.define("ury", new variable_reg(&ury_reg_contents));
}

object_dictionary request_dictionary(501);

void init_request(const char *s, REQUEST_FUNCP f)
{
  request_dictionary.define(s, new request(f));
}

static request_or_macro *lookup_request(symbol nm)
{
  assert(!nm.is_null());
  request_or_macro *p = (request_or_macro *)request_dictionary.lookup(nm);
  if (p == 0) {
    warning(WARN_MAC, "macro `%1' not defined", nm.contents());
    p = new macro;
    request_dictionary.define(nm, p);
  }
  return p;
}

node *charinfo_to_node_list(charinfo *ci, const environment *envp)
{
  // Don't interpret character definitions in compatible mode.
  int old_compatible_flag = compatible_flag;
  compatible_flag = 0;
  int old_escape_char = escape_char;
  escape_char = '\\';
  macro *mac = ci->set_macro(0);
  assert(mac != 0);
  environment *oldenv = curenv;
  environment env(envp);
  curenv = &env;
  curenv->set_composite();
  token old_tok = tok;
  input_stack::add_boundary();
  string_iterator *si =
    new string_iterator(*mac, "composite character", ci->nm);
  input_stack::push(si);
  // we don't use process_input_stack, because we don't want to recognise
  // requests
  for (;;) {
    tok.next();
    if (tok.eof())
      break;
    if (tok.newline()) {
      error("composite character mustn't contain newline");
      while (!tok.eof())
        tok.next();
      break;
    }
    else
      tok.process();
  }
  node *n = curenv->extract_output_line();
  input_stack::remove_boundary();
  ci->set_macro(mac);
  tok = old_tok;
  curenv = oldenv;
  compatible_flag = old_compatible_flag;
  escape_char = old_escape_char;
  have_input = 0;
  return n;
}

static node *read_draw_node()
{
  token start;
  start.next();
  if (!start.delimiter(1)){
    do {
      tok.next();
    } while (tok != start && !tok.newline() && !tok.eof());
  }
  else {
    tok.next();
    if (tok == start)
      error("missing argument");
    else {
      unsigned char type = tok.ch();
      if (type == 'F') {
        read_color_draw_node(start);
        return 0;
      }
      tok.next();
      int maxpoints = 10;
      hvpair *point = new hvpair[maxpoints];
      int npoints = 0;
      int no_last_v = 0;
      int err = 0;
      int i;
      for (i = 0; tok != start; i++) {
        if (i == maxpoints) {
          hvpair *oldpoint = point;
          point = new hvpair[maxpoints*2];
          for (int j = 0; j < maxpoints; j++)
            point[j] = oldpoint[j];
          maxpoints *= 2;
          a_delete oldpoint;
        }
        if (!get_hunits(&point[i].h,
                        type == 'f' || type == 't' ? 'u' : 'm')) {
          err = 1;
          break;
        }
        ++npoints;
        tok.skip();
        point[i].v = V0;
        if (tok == start) {
          no_last_v = 1;
          break;
        }
        if (!get_vunits(&point[i].v, 'v')) {
          err = 1;
          break;
        }
        tok.skip();
      }
      while (tok != start && !tok.newline() && !tok.eof())
        tok.next();
      if (!err) {
        switch (type) {
        case 'l':
          if (npoints != 1 || no_last_v) {
            error("two arguments needed for line");
            npoints = 1;
          }
          break;
        case 'c':
          if (npoints != 1 || !no_last_v) {
            error("one argument needed for circle");
            npoints = 1;
            point[0].v = V0;
          }
          break;
        case 'e':
          if (npoints != 1 || no_last_v) {
            error("two arguments needed for ellipse");
            npoints = 1;
          }
          break;
        case 'a':
          if (npoints != 2 || no_last_v) {
            error("four arguments needed for arc");
            npoints = 2;
          }
          break;
        case '~':
          if (no_last_v)
            error("even number of arguments needed for spline");
          break;
        case 'f':
          if (npoints != 1 || !no_last_v) {
            error("one argument needed for gray shade");
            npoints = 1;
            point[0].v = V0;
          }
        default:
          // silently pass it through
          break;
        }
        draw_node *dn = new draw_node(type, point, npoints,
                                      curenv->get_font_size(),
                                      curenv->get_glyph_color(),
                                      curenv->get_fill_color());
        a_delete point;
        return dn;
      }
      else {
        a_delete point;
      }
    }
  }
  return 0;
}

static void read_color_draw_node(token &start)
{
  tok.next();
  if (tok == start) {
    error("missing color scheme");
    return;
  }
  unsigned char scheme = tok.ch();
  tok.next();
  color *col = 0;
  char end = start.ch();
  switch (scheme) {
  case 'c':
    col = read_cmy(end);
    break;
  case 'd':
    col = &default_color;
    break;
  case 'g':
    col = read_gray(end);
    break;
  case 'k':
    col = read_cmyk(end);
    break;
  case 'r':
    col = read_rgb(end);
    break;
  }
  if (col)
    curenv->set_fill_color(col);
  while (tok != start) {
    if (tok.newline() || tok.eof()) {
      warning(WARN_DELIM, "missing closing delimiter");
      input_stack::push(make_temp_iterator("\n"));
      break;
    }
    tok.next();
  }
  have_input = 1;
}

static struct {
  const char *name;
  int mask;
} warning_table[] = {
  { "char", WARN_CHAR },
  { "range", WARN_RANGE },
  { "break", WARN_BREAK },
  { "delim", WARN_DELIM },
  { "el", WARN_EL },
  { "scale", WARN_SCALE },
  { "number", WARN_NUMBER },
  { "syntax", WARN_SYNTAX },
  { "tab", WARN_TAB },
  { "right-brace", WARN_RIGHT_BRACE },
  { "missing", WARN_MISSING },
  { "input", WARN_INPUT },
  { "escape", WARN_ESCAPE },
  { "space", WARN_SPACE },
  { "font", WARN_FONT },
  { "di", WARN_DI },
  { "mac", WARN_MAC },
  { "reg", WARN_REG },
  { "ig", WARN_IG },
  { "color", WARN_COLOR },
  { "all", WARN_TOTAL & ~(WARN_DI | WARN_MAC | WARN_REG) },
  { "w", WARN_TOTAL },
  { "default", DEFAULT_WARNING_MASK },
};

static int lookup_warning(const char *name)
{
  for (unsigned int i = 0;
       i < sizeof(warning_table)/sizeof(warning_table[0]);
       i++)
    if (strcmp(name, warning_table[i].name) == 0)
      return warning_table[i].mask;
  return 0;
}

static void enable_warning(const char *name)
{
  int mask = lookup_warning(name);
  if (mask)
    warning_mask |= mask;
  else
    error("unknown warning `%1'", name);
}

static void disable_warning(const char *name)
{
  int mask = lookup_warning(name);
  if (mask)
    warning_mask &= ~mask;
  else
    error("unknown warning `%1'", name);
}

static void copy_mode_error(const char *format,
                            const errarg &arg1,
                            const errarg &arg2,
                            const errarg &arg3)
{
  if (ignoring) {
    static const char prefix[] = "(in ignored input) ";
    char *s = new char[sizeof(prefix) + strlen(format)];
    strcpy(s, prefix);
    strcat(s, format);
    warning(WARN_IG, s, arg1, arg2, arg3);
    a_delete s;
  }
  else
    error(format, arg1, arg2, arg3);
}

enum error_type { WARNING, OUTPUT_WARNING, ERROR, FATAL };

static void do_error(error_type type,
                     const char *format,
                     const errarg &arg1,
                     const errarg &arg2,
                     const errarg &arg3)
{
  const char *filename;
  int lineno;
  if (inhibit_errors && type < FATAL)
    return;
  if (backtrace_flag)
    input_stack::backtrace();
  if (!get_file_line(&filename, &lineno))
    filename = 0;
  if (filename)
    errprint("%1:%2: ", filename, lineno);
  else if (program_name)
    fprintf(stderr, "%s: ", program_name);
  switch (type) {
  case FATAL:
    fputs("fatal error: ", stderr);
    break;
  case ERROR:
    break;
  case WARNING:
    fputs("warning: ", stderr);
    break;
  case OUTPUT_WARNING:
    double fromtop = topdiv->get_vertical_position().to_units() / warn_scale;
    fprintf(stderr, "warning [p %d, %.1f%c",
            topdiv->get_page_number(), fromtop, warn_scaling_indicator);
    if (topdiv != curdiv) {
      double fromtop1 = curdiv->get_vertical_position().to_units()
                        / warn_scale;
      fprintf(stderr, ", div `%s', %.1f%c",
              curdiv->get_diversion_name(), fromtop1, warn_scaling_indicator);
    }
    fprintf(stderr, "]: ");
    break;
  }
  errprint(format, arg1, arg2, arg3);
  fputc('\n', stderr);
  fflush(stderr);
  if (type == FATAL)
    cleanup_and_exit(1);
}

int warning(warning_type t,
            const char *format,
            const errarg &arg1,
            const errarg &arg2,
            const errarg &arg3)
{
  if ((t & warning_mask) != 0) {
    do_error(WARNING, format, arg1, arg2, arg3);
    return 1;
  }
  else
    return 0;
}

int output_warning(warning_type t,
                   const char *format,
                   const errarg &arg1,
                   const errarg &arg2,
                   const errarg &arg3)
{
  if ((t & warning_mask) != 0) {
    do_error(OUTPUT_WARNING, format, arg1, arg2, arg3);
    return 1;
  }
  else
    return 0;
}

void error(const char *format,
           const errarg &arg1,
           const errarg &arg2,
           const errarg &arg3)
{
  do_error(ERROR, format, arg1, arg2, arg3);
}

void fatal(const char *format,
           const errarg &arg1,
           const errarg &arg2,
           const errarg &arg3)
{
  do_error(FATAL, format, arg1, arg2, arg3);
}

void fatal_with_file_and_line(const char *filename, int lineno,
                              const char *format,
                              const errarg &arg1,
                              const errarg &arg2,
                              const errarg &arg3)
{
  fprintf(stderr, "%s:%d: fatal error: ", filename, lineno);
  errprint(format, arg1, arg2, arg3);
  fputc('\n', stderr);
  fflush(stderr);
  cleanup_and_exit(1);
}

void error_with_file_and_line(const char *filename, int lineno,
                              const char *format,
                              const errarg &arg1,
                              const errarg &arg2,
                              const errarg &arg3)
{
  fprintf(stderr, "%s:%d: error: ", filename, lineno);
  errprint(format, arg1, arg2, arg3);
  fputc('\n', stderr);
  fflush(stderr);
}

dictionary charinfo_dictionary(501);

charinfo *get_charinfo(symbol nm)
{
  void *p = charinfo_dictionary.lookup(nm);
  if (p != 0)
    return (charinfo *)p;
  charinfo *cp = new charinfo(nm);
  (void)charinfo_dictionary.lookup(nm, cp);
  return cp;
}

int charinfo::next_index = 0;

charinfo::charinfo(symbol s)
: translation(0), mac(0), special_translation(TRANSLATE_NONE),
  hyphenation_code(0), flags(0), ascii_code(0), asciify_code(0),
  not_found(0), transparent_translate(1), translate_input(0),
  mode(CHAR_NORMAL), nm(s)
{
  index = next_index++;
  number = -1;
}

void charinfo::set_hyphenation_code(unsigned char c)
{
  hyphenation_code = c;
}

void charinfo::set_translation(charinfo *ci, int tt, int ti)
{
  translation = ci;
  if (ci && ti) {
    if (hyphenation_code != 0)
      ci->set_hyphenation_code(hyphenation_code);
    if (asciify_code != 0)
      ci->set_asciify_code(asciify_code);
    else if (ascii_code != 0)
      ci->set_asciify_code(ascii_code);
    ci->set_translation_input();
  }
  special_translation = TRANSLATE_NONE;
  transparent_translate = tt;
}

void charinfo::set_special_translation(int c, int tt)
{
  special_translation = c;
  translation = 0;
  transparent_translate = tt;
}

void charinfo::set_ascii_code(unsigned char c)
{
  ascii_code = c;
}

void charinfo::set_asciify_code(unsigned char c)
{
  asciify_code = c;
}

macro *charinfo::set_macro(macro *m)
{
  macro *tem = mac;
  mac = m;
  return tem;
}

macro *charinfo::setx_macro(macro *m, char_mode cm)
{
  macro *tem = mac;
  mac = m;
  mode = cm;
  return tem;
}

void charinfo::set_number(int n)
{
  assert(n >= 0);
  number = n;
}

int charinfo::get_number()
{
  assert(number >= 0);
  return number;
}

symbol UNNAMED_SYMBOL("---");

// For numbered characters not between 0 and 255, we make a symbol out
// of the number and store them in this dictionary.

dictionary numbered_charinfo_dictionary(11);

charinfo *get_charinfo_by_number(int n)
{
  static charinfo *number_table[256];

  if (n >= 0 && n < 256) {
    charinfo *ci = number_table[n];
    if (!ci) {
      ci = new charinfo(UNNAMED_SYMBOL);
      ci->set_number(n);
      number_table[n] = ci;
    }
    return ci;
  }
  else {
    symbol ns(i_to_a(n));
    charinfo *ci = (charinfo *)numbered_charinfo_dictionary.lookup(ns);
    if (!ci) {
      ci = new charinfo(UNNAMED_SYMBOL);
      ci->set_number(n);
      (void)numbered_charinfo_dictionary.lookup(ns, ci);
    }
    return ci;
  }
}

// This overrides the same function from libgroff; while reading font
// definition files it puts single-letter glyph names into `charset_table'
// and converts glyph names of the form `\x' (`x' a single letter) into `x'. 
// Consequently, symbol("x") refers to glyph name `\x', not `x'.

glyph *name_to_glyph(const char *nm)
{
  charinfo *ci;
  if (nm[1] == 0)
    ci = charset_table[nm[0] & 0xff];
  else if (nm[0] == '\\' && nm[2] == 0)
    ci = get_charinfo(symbol(nm + 1));
  else
    ci = get_charinfo(symbol(nm));
  return ci->as_glyph();
}

glyph *number_to_glyph(int n)
{
  return get_charinfo_by_number(n)->as_glyph();
}

const char *glyph_to_name(glyph *g)
{
  charinfo *ci = (charinfo *)g; // Every glyph is actually a charinfo.
  return (ci->nm != UNNAMED_SYMBOL ? ci->nm.contents() : NULL);
}