Sync changes from latest snowball compiler version

[xapian.git] / xapian-core / languages / compiler / generator.c

#include <limits.h>  /* for INT_MAX */
#include <stdio.h>   /* for fprintf etc */
#include <stdlib.h>  /* for free etc */
#include <string.h>  /* for strlen */
#include "header.h"

/* Define this to get warning messages when optimisations can't be used. */
/* #define OPTIMISATION_WARNINGS */

/* recursive use: */

static void generate(struct generator * g, struct node * p);

enum special_labels {

    x_return = -1

};

static int new_label(struct generator * g) {
    return g->next_label++;
}

/* Write routines for simple entities */

/* Write a space if the preceding character was not whitespace */
static void ws_opt_space(struct generator * g, const char * s) {
    int ch = str_back(g->outbuf);
    if (ch != ' ' && ch != '\n' && ch != '\t' && ch != -1)
        write_char(g, ' ');
    write_string(g, s);
}

static void wi3(struct generator * g, int i) {
    if (i < 100) write_char(g, ' ');
    if (i < 10)  write_char(g, ' ');
    write_int(g, i); /* integer (width 3) */
}


/* Write routines for items from the syntax tree */

static void write_varname(struct generator * g, struct name * p) {

    int ch = "SBIrxg"[p->type];
    switch (p->type) {
        case t_external:
            write_string(g, g->options->externals_prefix); break;
        case t_string:
        case t_boolean:
        case t_integer:
            if (g->options->make_lang == LANG_C) {
                write_char(g, ch);
                write_char(g, '[');
                write_int(g, p->count);
                write_char(g, ']');
                return;
            }
            /* FALLTHRU */
        default:
            write_char(g, ch); write_char(g, '_');
    }
    str_append_b(g->outbuf, p->b);
}

static void write_varref(struct generator * g, struct name * p) {  /* reference to variable */
    if (g->options->make_lang == LANG_C && p->type < t_routine)
        write_string(g, "z->");
    write_varname(g, p);
}

static void write_hexdigit(struct generator * g, int i) {
    str_append_ch(g->outbuf, "0123456789ABCDEF"[i & 0xF]); /* hexchar */
}

static void write_hex(struct generator * g, int i) {
    if (i >> 4) write_hex(g, i >> 4);
    write_hexdigit(g, i); /* hex integer */
}

/* write character literal */
static void wlitch(struct generator * g, int ch) {
    if (32 <= ch && ch < 127) {
        write_char(g, '\'');
        if (ch == '\'' || ch == '\\') {
            write_char(g, '\\');
        }
        write_char(g, ch);
        write_char(g, '\'');
    }  else {
        write_string(g, "0x"); write_hex(g, ch);
    }
}

static void wlitarray(struct generator * g, symbol * p) {  /* write literal array */

    {
        int i;
        for (i = 0; i < SIZE(p); i++) {
            wlitch(g, p[i]);
            if (i < SIZE(p) - 1) write_string(g, ", ");
        }
    }
}

static void wlitref(struct generator * g, symbol * p) {  /* write ref to literal array */

    if (SIZE(p) == 0) write_char(g, '0'); else {
        struct str * s = g->outbuf;
        g->outbuf = g->declarations;
        write_string(g, "static const symbol s_"); write_int(g, g->literalstring_count); write_string(g, "[] = { ");
        wlitarray(g, p);
        write_string(g, " };\n");
        g->outbuf = s;
        write_string(g, "s_"); write_int(g, g->literalstring_count);
        g->literalstring_count++;
    }
}

static void write_margin(struct generator * g) {
    int i;
    for (i = 0; i < g->margin; i++) write_string(g, "    ");
}

static void write_comment(struct generator * g, struct node * p) {

    ws_opt_space(g, "/* ");
    switch (p->type) {
        case c_mathassign:
        case c_plusassign:
        case c_minusassign:
        case c_multiplyassign:
        case c_divideassign:
        case c_eq:
        case c_ne:
        case c_gr:
        case c_ge:
        case c_ls:
        case c_le:
            if (p->name) {
                write_char(g, '$');
                str_append_b(g->outbuf, p->name->b);
                write_char(g, ' ');
            }
            write_string(g, name_of_token(p->type));
            write_string(g, " <integer expression>");
            break;
        default:
            write_string(g, name_of_token(p->type));
            if (p->name) {
                write_char(g, ' ');
                str_append_b(g->outbuf, p->name->b);
            }
    }
    write_string(g, ", line "); write_int(g, p->line_number); write_string(g, " */");
    write_newline(g);
}

static void wms(struct generator * g, const char * s) {
    write_margin(g); write_string(g, s);   } /* margin + string */

static void write_block_start(struct generator * g) { /* block start */
    wms(g, "{   ");
    g->margin++;
}

static void write_block_end(struct generator * g) {    /* block end */

    if (g->line_labelled == g->line_count) { wms(g, ";"); write_newline(g); }
    g->margin--;
    wms(g, "}"); write_newline(g);
}

static void w(struct generator * g, const char * s);

/* keep c */
static void wk(struct generator * g, struct node * p, int keep_limit) {
    ++g->keep_count;
    if (p->mode == m_forward) {
        write_string(g, "int c");
        write_int(g, g->keep_count);
        w(g, " = ~zc");
        if (keep_limit) {
            write_string(g, ", mlimit");
            write_int(g, g->keep_count);
        }
        write_char(g, ';');
    } else {
        write_string(g, "int m");
        write_int(g, g->keep_count);
        w(g, " = ~zl - ~zc");
        if (keep_limit) {
            write_string(g, ", mlimit");
            write_int(g, g->keep_count);
        }
        write_string(g, "; (void)m");
        write_int(g, g->keep_count);
        write_char(g, ';');
    }
}

static void wrestore(struct generator * g, struct node * p, int keep_token) {     /* restore c */
    if (p->mode == m_forward) {
        w(g, "~zc = c");
    } else {
        w(g, "~zc = ~zl - m");
    }
    write_int(g, keep_token); write_char(g, ';');
}

static void wrestorelimit(struct generator * g, struct node * p, int keep_token) {     /* restore limit */
    if (p->mode == m_forward) {
        w(g, "~zl += mlimit");
    } else {
        w(g, "~zlb = mlimit");
    }
    write_int(g, keep_token); write_string(g, ";");
}

static void winc(struct generator * g, struct node * p) {     /* increment c */
    w(g, p->mode == m_forward ? "~zc++;" :
                                "~zc--;");
}

static void wsetl(struct generator * g, int n) {

    g->margin--;
    wms(g, "lab"); write_int(g, n); write_char(g, ':'); write_newline(g);
    g->line_labelled = g->line_count;
    g->margin++;
}

static void wgotol(struct generator * g, int n) {
    wms(g, "goto lab"); write_int(g, n); write_char(g, ';'); write_newline(g);
}

static void write_failure(struct generator * g, struct node * p) {          /* fail */
    if (g->failure_keep_count != 0) {
        write_string(g, "{ ");
        if (g->failure_keep_count > 0) {
            wrestore(g, p, g->failure_keep_count);
        } else {
            wrestorelimit(g, p, -g->failure_keep_count);
        }
        write_char(g, ' ');
    }
    switch (g->failure_label)
    {
        case x_return:
            write_string(g, "return 0;");
            break;
        default:
            write_string(g, "goto lab");
            write_int(g, g->failure_label);
            write_char(g, ';');
            g->label_used = 1;
    }
    if (g->failure_keep_count != 0) write_string(g, " }");
}


/* if at limit fail */
static void write_check_limit(struct generator * g, struct node * p) {

    w(g, p->mode == m_forward ? "if (~zc >= ~zl) " :
                                "if (~zc <= ~zlb) ");
    write_failure(g, p);
}

static void write_data_address(struct generator * g, struct node * p) {
    symbol * b = p->literalstring;
    if (b != 0) {
        write_int(g, SIZE(b)); w(g, ", ");
        wlitref(g, b);
    } else {
        write_varref(g, p->name);
    }
}

/* Formatted write. */
static void writef(struct generator * g, const char * input, struct node * p) {
    int i = 0;
    int l = strlen(input);

    while (i < l) {
        int ch = input[i++];
        if (ch != '~') {
            write_char(g, ch);
            continue;
        }
        switch (input[i++]) {
            default: write_char(g, input[i - 1]); continue;
            case 'C': write_comment(g, p); continue;
            case 'k': wk(g, p, false); continue;
            case 'K': wk(g, p, true); continue;
            case 'i': winc(g, p); continue;
            case 'l': write_check_limit(g, p); continue;
            case 'f': write_failure(g, p); continue;
            case 'M': write_margin(g); continue;
            case 'N': write_newline(g); continue;
            case '{': write_block_start(g); continue;
            case '}': write_block_end(g); continue;
            case 'S': write_string(g, g->S[input[i++] - '0']); continue;
            case 'I': write_int(g, g->I[input[i++] - '0']); continue;
            case 'J': wi3(g, g->I[input[i++] - '0']); continue;
            case 'V': write_varref(g, g->V[input[i++] - '0']); continue;
            case 'W': write_varname(g, g->V[input[i++] - '0']); continue;
            case 'L': wlitref(g, g->L[input[i++] - '0']); continue;
            case 'A': wlitarray(g, g->L[input[i++] - '0']); continue;
            case 'c': wlitch(g, g->I[input[i++] - '0']); continue;
            case 'a': write_data_address(g, p); continue;
            case '+': g->margin++; continue;
            case '-': g->margin--; continue;
            case '$': /* insert_s, insert_v etc */
                write_char(g, p->literalstring == 0 ? 'v' : 's');
                continue;
            case 'z':
                if (g->options->make_lang == LANG_C)
                    write_string(g, "z->");
                continue;
            case 'Z':
                if (g->options->make_lang == LANG_C)
                    write_string(g, input[i] == ')' ? "z" : "z, ");
                continue;
            case 'p': write_string(g, g->options->externals_prefix); continue;
        }
    }
}

static void w(struct generator * g, const char * s) {
    writef(g, s, 0);
}

static void generate_AE(struct generator * g, struct node * p) {
    const char * s;
    switch (p->type) {
        case c_name:
            write_varref(g, p->name); break;
        case c_number:
            write_int(g, p->number); break;
        case c_maxint:
            write_string(g, "MAXINT"); break;
        case c_minint:
            write_string(g, "MININT"); break;
        case c_neg:
            write_char(g, '-'); generate_AE(g, p->right); break;
        case c_multiply:
            s = " * "; goto label0;
        case c_plus:
            s = " + "; goto label0;
        case c_minus:
            s = " - "; goto label0;
        case c_divide:
            s = " / ";
        label0:
            write_char(g, '('); generate_AE(g, p->left);
            write_string(g, s); generate_AE(g, p->right); write_char(g, ')'); break;
        case c_cursor:
            w(g, "~zc"); break;
        case c_limit:
            w(g, p->mode == m_forward ? "~zl" : "~zlb"); break;
        case c_len:
            if (g->options->encoding == ENC_UTF8) {
                w(g, "len_utf8(~zp)");
                break;
            }
            /* FALLTHRU */
        case c_size:
            w(g, "SIZE(~zp)");
            break;
        case c_lenof:
            if (g->options->encoding == ENC_UTF8) {
                g->V[0] = p->name;
                w(g, "len_utf8(~V0)");
                break;
            }
            /* FALLTHRU */
        case c_sizeof:
            g->V[0] = p->name;
            w(g, "SIZE(~V0)");
            break;
    }
}

/* K_needed() tests to see if we really need to keep c. Not true when the
   command does not touch the cursor. This and repeat_score() could be
   elaborated almost indefinitely.
*/

static int K_needed_(struct generator * g, struct node * p, int call_depth) {
    while (p) {
        switch (p->type) {
            case c_atlimit:
            case c_do:
            case c_dollar:
            case c_leftslice:
            case c_rightslice:
            case c_mathassign:
            case c_plusassign:
            case c_minusassign:
            case c_multiplyassign:
            case c_divideassign:
            case c_eq:
            case c_ne:
            case c_gr:
            case c_ge:
            case c_ls:
            case c_le:
            case c_sliceto:
            case c_booltest:
            case c_set:
            case c_unset:
            case c_true:
            case c_false:
            case c_debug:
                break;

            case c_call:
                /* Recursive functions aren't typical in snowball programs, so
                 * make the pessimistic assumption that keep is needed if we
                 * hit a generous limit on recursion.  It's not likely to make
                 * a difference to any real world program, but means we won't
                 * recurse until we run out of stack for pathological cases.
                 */
                if (call_depth >= 100) return true;
                if (K_needed_(g, p->name->definition, call_depth + 1))
                    return true;
                break;

            case c_bra:
                if (K_needed_(g, p->left, call_depth)) return true;
                break;

            default: return true;
        }
        p = p->right;
    }
    return false;
}

extern int K_needed(struct generator * g, struct node * p) {
    return K_needed_(g, p, 0);
}

static int repeat_score(struct generator * g, struct node * p, int call_depth) {
    int score = 0;
    while (p) {
        switch (p->type) {
            case c_dollar:
            case c_leftslice:
            case c_rightslice:
            case c_mathassign:
            case c_plusassign:
            case c_minusassign:
            case c_multiplyassign:
            case c_divideassign:
            case c_eq:
            case c_ne:
            case c_gr:
            case c_ge:
            case c_ls:
            case c_le:
            case c_sliceto:   /* case c_not: must not be included here! */
            case c_debug:
                break;

            case c_call:
                /* Recursive functions aren't typical in snowball programs, so
                 * make the pessimistic assumption that repeat requires cursor
                 * reinstatement if we hit a generous limit on recursion.  It's
                 * not likely to make a difference to any real world program,
                 * but means we won't recurse until we run out of stack for
                 * pathological cases.
                 */
                if (call_depth >= 100) {
                    return 2;
                }
                score += repeat_score(g, p->name->definition, call_depth + 1);
                if (score >= 2)
                    return score;
                break;

            case c_bra:
                score += repeat_score(g, p->left, call_depth);
                if (score >= 2)
                    return score;
                break;

            case c_name:
            case c_literalstring:
            case c_next:
            case c_grouping:
            case c_non:
            case c_hop:
                if (++score >= 2)
                    return score;
                break;

            default:
                return 2;
        }
        p = p->right;
    }
    return score;
}

/* tests if an expression requires cursor reinstatement in a repeat */

extern int repeat_restore(struct generator * g, struct node * p) {
    return repeat_score(g, p, 0) >= 2;
}

static void generate_bra(struct generator * g, struct node * p) {
    p = p->left;
    while (p) {
        generate(g, p);
        p = p->right;
    }
}

static void generate_and(struct generator * g, struct node * p) {
    int keep_c = 0;
    if (K_needed(g, p->left)) {
        writef(g, "~{~k~C", p);
        keep_c = g->keep_count;
    } else {
        writef(g, "~M~C", p);
    }
    p = p->left;
    while (p) {
        generate(g, p);
        if (keep_c && p->right != 0) {
            w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
        }
        p = p->right;
    }
    if (keep_c) w(g, "~}");
}

static void generate_or(struct generator * g, struct node * p) {
    int keep_c = 0;

    int used = g->label_used;
    int a0 = g->failure_label;
    int a1 = g->failure_keep_count;

    int out_lab = new_label(g);

    if (K_needed(g, p->left)) {
        writef(g, "~{~k~C", p);
        keep_c = g->keep_count;
    } else {
        writef(g, "~M~C", p);
    }
    p = p->left;
    g->failure_keep_count = 0;
    while (p->right) {
        g->failure_label = new_label(g);
        g->label_used = 0;
        generate(g, p);
        wgotol(g, out_lab);
        if (g->label_used)
            wsetl(g, g->failure_label);
        if (keep_c) {
            w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
        }
        p = p->right;
    }
    g->label_used = used;
    g->failure_label = a0;
    g->failure_keep_count = a1;

    generate(g, p);
    if (keep_c) w(g, "~}");
    wsetl(g, out_lab);
}

static void generate_backwards(struct generator * g, struct node * p) {

    writef(g, "~M~zlb = ~zc; ~zc = ~zl;~C~N", p);
    generate(g, p->left);
    w(g, "~M~zc = ~zlb;~N");
}


static void generate_not(struct generator * g, struct node * p) {
    int keep_c = 0;

    int used = g->label_used;
    int a0 = g->failure_label;
    int a1 = g->failure_keep_count;

    if (K_needed(g, p->left)) {
        writef(g, "~{~k~C", p);
        keep_c = g->keep_count;
    } else {
        writef(g, "~M~C", p);
    }

    g->failure_label = new_label(g);
    g->label_used = 0;
    g->failure_keep_count = 0;
    generate(g, p->left);

    {
        int l = g->failure_label;
        int u = g->label_used;

        g->label_used = used;
        g->failure_label = a0;
        g->failure_keep_count = a1;

        writef(g, "~M~f~N", p);
        if (u)
            wsetl(g, l);
    }
    if (keep_c) {
        w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N~}");
    }
}


static void generate_try(struct generator * g, struct node * p) {
    int keep_c = 0;
    if (K_needed(g, p->left)) {
        writef(g, "~{~k~C", p);
        keep_c = g->keep_count;
    } else {
        writef(g, "~M~C", p);
    }
    g->failure_keep_count = keep_c;

    g->failure_label = new_label(g);
    g->label_used = 0;
    generate(g, p->left);

    if (g->label_used)
        wsetl(g, g->failure_label);

    if (keep_c) w(g, "~}");
}

static void generate_set(struct generator * g, struct node * p) {
    g->V[0] = p->name; writef(g, "~M~V0 = 1;~C", p);
}

static void generate_unset(struct generator * g, struct node * p) {
    g->V[0] = p->name; writef(g, "~M~V0 = 0;~C", p);
}

static void generate_fail(struct generator * g, struct node * p) {
    generate(g, p->left);
    writef(g, "~M~f~C", p);
}

/* generate_test() also implements 'reverse' */

static void generate_test(struct generator * g, struct node * p) {
    int keep_c = 0;
    if (K_needed(g, p->left)) {
        keep_c = ++g->keep_count;
        w(g, p->mode == m_forward ? "~{int c_test" :
                                    "~{int m_test");
        write_int(g, keep_c);
        w(g, p->mode == m_forward ? " = ~zc;" :
                                    " = ~zl - ~zc;");
        writef(g, "~C", p);
    } else writef(g, "~M~C", p);

    generate(g, p->left);

    if (keep_c) {
        w(g, p->mode == m_forward ? "~M~zc = c_test" :
                                    "~M~zc = ~zl - m_test");
        write_int(g, keep_c);
        writef(g, ";~N~}", p);
    }
}

static void generate_do(struct generator * g, struct node * p) {
    int keep_c = 0;
    if (K_needed(g, p->left)) {
        writef(g, "~{~k~C", p);
        keep_c = g->keep_count;
    } else {
        writef(g, "~M~C", p);
    }

    g->failure_label = new_label(g);
    g->label_used = 0;
    g->failure_keep_count = 0;
    generate(g, p->left);

    if (g->label_used)
        wsetl(g, g->failure_label);
    if (keep_c) {
        w(g, "~M"); wrestore(g, p, keep_c);
        w(g, "~N~}");
    }
}

static void generate_next(struct generator * g, struct node * p) {
    if (g->options->encoding == ENC_UTF8) {
        if (p->mode == m_forward)
            w(g, "~{int ret = skip_utf8(~zp, ~zc, 0, ~zl, 1");
        else
            w(g, "~{int ret = skip_utf8(~zp, ~zc, ~zlb, 0, -1");
        writef(g, ");~N"
              "~Mif (ret < 0) ~f~N"
              "~M~zc = ret;~C"
              "~}", p);
    } else
        writef(g, "~M~l~N"
              "~M~i~C", p);
}

static void generate_GO_grouping(struct generator * g, struct node * p, int is_goto, int complement) {

    struct grouping * q = p->name->grouping;
    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->S[1] = complement ? "in" : "out";
    g->S[2] = g->options->encoding == ENC_UTF8 ? "_U" : "";
    g->V[0] = p->name;
    g->I[0] = q->smallest_ch;
    g->I[1] = q->largest_ch;
    if (is_goto) {
        writef(g, "~Mif (~S1_grouping~S0~S2(~Z~V0, ~I0, ~I1, 1) < 0) ~f /* goto */~C", p);
    } else {
        writef(g, "~{ /* gopast */~C"
              "~Mint ret = ~S1_grouping~S0~S2(~Z~V0, ~I0, ~I1, 1);~N"
              "~Mif (ret < 0) ~f~N", p);
        if (p->mode == m_forward)
            w(g, "~M~zc += ret;~N");
        else
            w(g, "~M~zc -= ret;~N");
        w(g, "~}");
    }
}

static void generate_GO(struct generator * g, struct node * p, int style) {
    int keep_c = 0;

    int used = g->label_used;
    int a0 = g->failure_label;
    int a1 = g->failure_keep_count;

    if (p->left->type == c_grouping || p->left->type == c_non) {
        /* Special case for "goto" or "gopast" when used on a grouping or an
         * inverted grouping - the movement of c by the matching action is
         * exactly what we want! */
#ifdef OPTIMISATION_WARNINGS
        printf("Optimising %s %s\n", style ? "goto" : "gopast", p->left->type == c_non ? "non" : "grouping");
#endif
        generate_GO_grouping(g, p->left, style, p->left->type == c_non);
        return;
    }

    w(g, "~Mwhile(1) {"); writef(g, "~C~+", p);

    if (style == 1 || repeat_restore(g, p->left)) {
        writef(g, "~M~k~N", p);
        keep_c = g->keep_count;
    }

    g->failure_label = new_label(g);
    g->label_used = 0;
    generate(g, p->left);

    if (style == 1) {
        /* include for goto; omit for gopast */
        w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
    }
    w(g, "~Mbreak;~N");
    if (g->label_used)
        wsetl(g, g->failure_label);
    if (keep_c) {
        w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
    }

    g->label_used = used;
    g->failure_label = a0;
    g->failure_keep_count = a1;

/*  writef(g, "~M~l~N"
          "~M~i~N", p);  */
    generate_next(g, p);
    w(g, "~}");
}

static void generate_loop(struct generator * g, struct node * p) {
    w(g, "~{int i; for (i = "); generate_AE(g, p->AE); writef(g, "; i > 0; i--)~C"
            "~{", p);

    generate(g, p->left);

    w(g,    "~}"
         "~}");
}

static void generate_repeat(struct generator * g, struct node * p, int atleast_case) {
    int keep_c = 0;
    writef(g, "~Mwhile(1) {~C~+", p);

    if (repeat_restore(g, p->left)) {
        writef(g, "~M~k~N", p);
        keep_c = g->keep_count;
    }

    g->failure_label = new_label(g);
    g->label_used = 0;
    g->failure_keep_count = 0;
    generate(g, p->left);

    if (atleast_case) w(g, "~Mi--;~N");

    w(g, "~Mcontinue;~N");
    if (g->label_used)
        wsetl(g, g->failure_label);

    if (keep_c) {
        w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
    }

    w(g, "~Mbreak;~N"
      "~}");
}

static void generate_atleast(struct generator * g, struct node * p) {
    w(g, "~{int i = "); generate_AE(g, p->AE); w(g, ";~N");
    {
        int used = g->label_used;
        int a0 = g->failure_label;
        int a1 = g->failure_keep_count;

        generate_repeat(g, p, true);

        g->label_used = used;
        g->failure_label = a0;
        g->failure_keep_count = a1;
    }
    writef(g, "~Mif (i > 0) ~f~N"
       "~}", p);
}

static void generate_setmark(struct generator * g, struct node * p) {
    g->V[0] = p->name;
    writef(g, "~M~V0 = ~zc;~C", p);
}

static void generate_tomark(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? ">" : "<";

    w(g, "~Mif (~zc ~S0 "); generate_AE(g, p->AE); writef(g, ") ~f~N", p);
    w(g, "~M~zc = "); generate_AE(g, p->AE); writef(g, ";~C", p);
}

static void generate_atmark(struct generator * g, struct node * p) {

    w(g, "~Mif (~zc != "); generate_AE(g, p->AE); writef(g, ") ~f~C", p);
}

static void generate_hop(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? "+" : "-";
    g->S[1] = p->mode == m_forward ? "0" :
        (g->options->make_lang == LANG_C ? "z->lb" : "lb");
    if (g->options->encoding == ENC_UTF8) {
        w(g, "~{int ret = skip_utf8(~zp, ~zc, ~S1, ~zl, ~S0 ");
        generate_AE(g, p->AE); writef(g, ");~C", p);
        writef(g, "~Mif (ret < 0) ~f~N", p);
    } else {
        w(g, "~{int ret = ~zc ~S0 ");
        generate_AE(g, p->AE); writef(g, ";~C", p);
        writef(g, "~Mif (~S1 > ret || ret > ~zl) ~f~N", p);
    }
    writef(g, "~M~zc = ret;~N"
          "~}", p);
}

static void generate_delete(struct generator * g, struct node * p) {
#if 1
    writef(g, "~Mif (slice_del(~Z) == -1) return -1;~C", p);
#else
    writef(g, "~{int ret = slice_del(~Z);~C", p);
    writef(g, "~Mif (ret < 0) return ret;~N"
          "~}", p);
#endif
}

static void generate_tolimit(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? "" : "b";
    writef(g, "~M~zc = ~zl~S0;~C", p);
}

static void generate_atlimit(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? "" : "b";
    g->S[1] = p->mode == m_forward ? "<" : ">";
    writef(g, "~Mif (~zc ~S1 ~zl~S0) ~f~C", p);
}

static void generate_leftslice(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? "bra" : "ket";
    writef(g, "~M~z~S0 = ~zc;~C", p);
}

static void generate_rightslice(struct generator * g, struct node * p) {
    g->S[0] = p->mode == m_forward ? "ket" : "bra";
    writef(g, "~M~z~S0 = ~zc;~C", p);
}

static void generate_assignto(struct generator * g, struct node * p) {
    g->V[0] = p->name;
    writef(g, "~M~V0 = assign_to(~Z~V0);~C", p);
    if (g->options->make_lang == LANG_C)
        writef(g, "~Mif (~V0 == 0) return -1;~C", p);
}

static void generate_sliceto(struct generator * g, struct node * p) {
    g->V[0] = p->name;
    writef(g, "~{symbol * ret = slice_to(~Z~V0);~C"
          "~Mif (ret == 0) return -1;~N"
          "~M~V0 = ret;~N"
          "~}", p);
}

static void generate_insert(struct generator * g, struct node * p, int style) {

    int keep_c = style == c_attach;
    if (p->mode == m_backward) keep_c = !keep_c;
    if (g->options->make_lang == LANG_C)
        writef(g, "~{int ret;~N", p);
    if (keep_c) w(g, "~{int saved_c = ~zc;~N");
    if (g->options->make_lang == LANG_C)
        writef(g, "~Mret = insert_~$(~Z~zc, ~zc, ~a);~C", p);
    else
        writef(g, "~Minsert_~$(~Z~zc, ~zc, ~a);~C", p);
    if (keep_c) w(g, "~M~zc = saved_c;~N~}");
    if (g->options->make_lang == LANG_C)
        writef(g, "~Mif (ret < 0) return ret;~N"
              "~}", p);
}

static void generate_assignfrom(struct generator * g, struct node * p) {

    int keep_c = p->mode == m_forward; /* like 'attach' */
    if (g->options->make_lang == LANG_C)
        writef(g, "~{int ret;~N", p);
    if (keep_c) writef(g, "~{int saved_c = ~zc;~N", p);
    w(g, g->options->make_lang == LANG_C ? "~Mret =" : "~M");
    writef(g, keep_c ? "insert_~$(~Z~zc, ~zl, ~a);~C" : "insert_~$(~Z~zlb, ~zc, ~a);~C", p);
    if (keep_c) w(g, "~M~zc = saved_c;~N~}");
    if (g->options->make_lang == LANG_C)
        writef(g, "~Mif (ret < 0) return ret;~N"
              "~}", p);
}

/* bugs marked <======= fixed 22/7/02. Similar fixes required for Java */

static void generate_slicefrom(struct generator * g, struct node * p) {

/*  w(g, "~Mslice_from_s(~Z");   <============= bug! should be: */
    writef(g, "~{int ret = slice_from_~$(~Z~a);~C", p);
    writef(g, "~Mif (ret < 0) return ret;~N"
          "~}", p);
}

static void generate_setlimit(struct generator * g, struct node * p) {
    int keep_c;
    if (p->left && p->left->type == c_tomark && !p->left->right) {
        /* Special case for:
         *
         *   setlimit tomark AE for C
         *
         * All uses of setlimit in the current stemmers we ship follow this
         * pattern, and by special-casing we can avoid having to save and
         * restore c.
         */
        struct node * q = p->left;

        ++g->keep_count;
        writef(g, "~N~{int mlimit", p);
        write_int(g, g->keep_count);
        writef(g, ";~C", p);
        keep_c = g->keep_count;

        g->S[0] = q->mode == m_forward ? ">" : "<";

        w(g, "~Mif (~zc ~S0 "); generate_AE(g, q->AE); writef(g, ") ~f~N", q);
        w(g, "~Mmlimit");
        write_int(g, keep_c);
        if (p->mode == m_forward) {
            w(g, " = ~zl - ~zc; ~zl = ");
        } else {
            w(g, " = ~zlb; ~zlb = ");
        }
        generate_AE(g, q->AE);
        w(g, ";~N");
    } else {
        writef(g, "~{~K~C", p);
        keep_c = g->keep_count;
        generate(g, p->left);

        w(g, "~Mmlimit");
        write_int(g, keep_c);
        if (p->mode == m_forward)
            w(g, " = ~zl - ~zc; ~zl = ~zc;~N");
        else
            w(g, " = ~zlb; ~zlb = ~zc;~N");
        w(g, "~M"); wrestore(g, p, keep_c); w(g, "~N");
    }

    g->failure_keep_count = -keep_c;
    generate(g, p->aux);
    w(g, "~M");
    wrestorelimit(g, p, -g->failure_keep_count);
    w(g, "~N"
      "~}");
}

static const char * vars[] = { "p", "c", "l", "lb", "bra", "ket", NULL };

/* dollar sets snowball up to operate on a string variable as if it were the
 * current string */
static void generate_dollar(struct generator * g, struct node * p) {

    int used = g->label_used;
    int a0 = g->failure_label;
    int a1 = g->failure_keep_count;
    int keep_token;
    g->failure_label = new_label(g);
    g->label_used = 0;
    g->failure_keep_count = 0;

    keep_token = ++g->keep_count;
    g->I[0] = keep_token;
    if (g->options->make_lang != LANG_C) {
        const char ** var;
        writef(g, "~{~C", p);
        for (var = vars; *var; ++var) {
            g->S[0] = *var;
            w(g, "~Mint ~S0~I0 = ~S0;~N");
        }
    } else {
        writef(g, "~{struct SN_env env~I0 = * z;~C", p);
    }
    g->V[0] = p->name;
    writef(g, "~Mint failure = 1; /* assume failure */~N"
          "~M~zp = ~V0;~N"
          "~M~zlb = ~zc = 0;~N"
          "~M~zl = SIZE(~zp);~N", p);
    generate(g, p->left);
    w(g, "~Mfailure = 0; /* mark success */~N");
    if (g->label_used)
        wsetl(g, g->failure_label);
    g->V[0] = p->name; /* necessary */

    g->label_used = used;
    g->failure_label = a0;
    g->failure_keep_count = a1;

    g->I[0] = keep_token;
    if (g->options->make_lang != LANG_C) {
        const char ** var;
        w(g, "~M~V0 = ~zp;~N");
        for (var = vars; *var; ++var) {
            g->S[0] = *var;
            w(g, "~M~S0 = ~S0~I0;~N");
        }
        writef(g, "~Mif (failure) ~f~N~}", p);
    } else {
        writef(g, "~M~V0 = z->p;~N"
              "~M* z = env~I0;~N"
              "~Mif (failure) ~f~N~}", p);
    }
}

static void generate_integer_assign(struct generator * g, struct node * p, char * s) {

    g->V[0] = p->name;
    g->S[0] = s;
    w(g, "~M~V0 ~S0 "); generate_AE(g, p->AE); writef(g, ";~C", p);
}

static void generate_integer_test(struct generator * g, struct node * p, char * s) {

    g->V[0] = p->name;
    g->S[0] = s;
    w(g, "~Mif (!(~V0 ~S0 "); generate_AE(g, p->AE); writef(g, ")) ~f~C", p);
}

static void generate_call(struct generator * g, struct node * p) {

    g->V[0] = p->name;
    writef(g, "~{int ret = ~V0(~Z);~C", p);
    if (g->failure_keep_count == 0 && g->failure_label == x_return) {
        /* Combine the two tests in this special case for better optimisation
         * and clearer generated code. */
        writef(g, "~Mif (ret <= 0) return ret;~N~}", p);
    } else {
        writef(g, "~Mif (ret == 0) ~f~N"
              "~Mif (ret < 0) return ret;~N~}", p);
    }
}

static void generate_grouping(struct generator * g, struct node * p, int complement) {

    struct grouping * q = p->name->grouping;
    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->S[1] = complement ? "out" : "in";
    g->S[2] = g->options->encoding == ENC_UTF8 ? "_U" : "";
    g->V[0] = p->name;
    g->I[0] = q->smallest_ch;
    g->I[1] = q->largest_ch;
    writef(g, "~Mif (~S1_grouping~S0~S2(~Z~V0, ~I0, ~I1, 0)) ~f~C", p);
}

static void generate_namedstring(struct generator * g, struct node * p) {

    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->V[0] = p->name;
    writef(g, "~Mif (!(eq_v~S0(~Z~V0))) ~f~C", p);
}

static void generate_literalstring(struct generator * g, struct node * p) {
    symbol * b = p->literalstring;
    if (SIZE(b) == 1) {
        /* It's quite common to compare with a single character literal string,
         * so just inline the simpler code for this case rather than making a
         * function call.  In UTF-8 mode, only do this for the ASCII subset,
         * since multi-byte characters are more complex to test against.
         */
        if (g->options->encoding == ENC_UTF8 && *b >= 128) {
            printf("single byte %d\n", *b);
            exit(1);
        }
        g->I[0] = *b;
        if (p->mode == m_forward) {
            writef(g, "~Mif (~zc == ~zl || ~zp[~zc] != ~c0) ~f~C"
                  "~M~zc++;~N", p);
        } else {
            writef(g, "~Mif (~zc <= ~zlb || ~zp[~zc - 1] != ~c0) ~f~C"
                  "~M~zc--;~N", p);
        }
    } else {
        g->S[0] = p->mode == m_forward ? "" : "_b";
        g->I[0] = SIZE(b);
        g->L[0] = b;

        writef(g, "~Mif (!(eq_s~S0(~Z~I0, ~L0))) ~f~C", p);
    }
}

static void generate_define(struct generator * g, struct node * p) {
    struct name * q = p->name;
    g->next_label = 0;

    if (g->options->make_lang == LANG_C)
        g->S[0] = q->type == t_routine ? "static" : "extern";
    else
        g->S[0] = g->options->name;
    g->V[0] = q;

    if (g->options->make_lang == LANG_C)
        w(g, "~N~S0 int ~V0(struct SN_env * z) {");
    else
        w(g, "~Nint Xapian::~S0::~V0() {");
    write_string(g, p->mode == m_forward ? " /* forwardmode */" : " /* backwardmode */");
    w(g, "~N~+");
    if (p->amongvar_needed) w(g, "~Mint among_var;~N");
    g->failure_keep_count = 0;
    g->failure_label = x_return;
    g->label_used = 0;
    g->keep_count = 0;
    generate(g, p->left);
    w(g, "~Mreturn 1;~N~}");
}

static void generate_substring(struct generator * g, struct node * p) {

    struct among * x = p->among;
    int block = -1;
    unsigned int bitmap = 0;
    struct amongvec * among_cases = x->b;
    int c;
    int empty_case = -1;
    int n_cases = 0;
    symbol cases[2];
    int shortest_size = INT_MAX;
    int shown_comment = 0;

    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->I[0] = x->number;
    g->I[1] = x->literalstring_count;

    /* In forward mode with non-ASCII UTF-8 characters, the first character
     * of the string will often be the same, so instead look at the last
     * common character position.
     *
     * In backward mode, we can't match if there are fewer characters before
     * the current position than the minimum length.
     */
    for (c = 0; c < x->literalstring_count; ++c) {
        int size = among_cases[c].size;
        if (size != 0 && size < shortest_size) {
            shortest_size = size;
        }
    }

    for (c = 0; c < x->literalstring_count; ++c) {
        symbol ch;
        if (among_cases[c].size == 0) {
            empty_case = c;
            continue;
        }
        if (p->mode == m_forward) {
            ch = among_cases[c].b[shortest_size - 1];
        } else {
            ch = among_cases[c].b[among_cases[c].size - 1];
        }
        if (n_cases == 0) {
            block = ch >> 5;
        } else if (ch >> 5 != block) {
            block = -1;
            if (n_cases > 2) break;
        }
        if (block == -1) {
            if (n_cases > 0 && ch == cases[0]) continue;
            if (n_cases < 2) {
                cases[n_cases++] = ch;
            } else if (ch != cases[1]) {
                ++n_cases;
                break;
            }
        } else {
            if ((bitmap & (1u << (ch & 0x1f))) == 0) {
                bitmap |= 1u << (ch & 0x1f);
                if (n_cases < 2)
                    cases[n_cases] = ch;
                ++n_cases;
            }
        }
    }

    if (block != -1 || n_cases <= 2) {
        char buf[64];
        g->I[2] = block;
        g->I[3] = bitmap;
        g->I[4] = shortest_size - 1;
        if (p->mode == m_forward) {
            const char * z = g->options->make_lang == LANG_C ? "z->" : "";
            sprintf(buf, "%sp[%sc + %d]", z, z, shortest_size - 1);
            g->S[1] = buf;
            if (shortest_size == 1) {
                writef(g, "~Mif (~zc >= ~zl", p);
            } else {
                writef(g, "~Mif (~zc + ~I4 >= ~zl", p);
            }
        } else {
            if (g->options->make_lang == LANG_C)
                g->S[1] = "z->p[z->c - 1]";
            else
                g->S[1] = "p[c - 1]";
            if (shortest_size == 1) {
                writef(g, "~Mif (~zc <= ~zlb", p);
            } else {
                writef(g, "~Mif (~zc - ~I4 <= ~zlb", p);
            }
        }
        if (n_cases == 0) {
            /* We get this for the degenerate case: among { '' }
             * This doesn't seem to be a useful construct, but it is
             * syntactically valid.
             */
        } else if (n_cases == 1) {
            g->I[4] = cases[0];
            writef(g, " || ~S1 != ~I4", p);
        } else if (n_cases == 2) {
            g->I[4] = cases[0];
            g->I[5] = cases[1];
            writef(g, " || (~S1 != ~I4 && ~S1 != ~I5)", p);
        } else {
            writef(g, " || ~S1 >> 5 != ~I2 || !((~I3 >> (~S1 & 0x1f)) & 1)", p);
        }
        write_string(g, ") ");
        if (empty_case != -1) {
            /* If the among includes the empty string, it can never fail
             * so not matching the bitmap means we match the empty string.
             */
            g->I[4] = among_cases[empty_case].result;
            writef(g, "among_var = ~I4; else~C", p);
        } else {
            writef(g, "~f~C", p);
        }
        shown_comment = 1;
    } else {
#ifdef OPTIMISATION_WARNINGS
        printf("Couldn't shortcut among %d\n", x->number);
#endif
    }

    if (x->command_count == 0 && x->starter == 0) {
        w(g, "~Mif (!(find_among~S0(s_pool, ~Za_~I0, ~I1, ");
        if (x->function_count) {
            w(g, "af_~I0, af");
        } else {
            write_string(g, "0, 0");
        }
        writef(g, "))) ~f", p);
        writef(g, shown_comment ? "~N" : "~C", p);
    } else {
        w(g, "~Mamong_var = find_among~S0(s_pool, ~Za_~I0, ~I1, ");
        if (x->function_count) {
            w(g, "af_~I0, af");
        } else {
            write_string(g, "0, 0");
        }
        writef(g, ");", p);
        writef(g, shown_comment ? "~N" : "~C", p);
        writef(g, "~Mif (!(among_var)) ~f~N", p);
    }
}

static void generate_among(struct generator * g, struct node * p) {

    struct among * x = p->among;
    int case_number = 1;

    if (x->substring == 0) generate_substring(g, p);
    if (x->command_count == 0 && x->starter == 0) return;

    if (x->starter != 0) generate(g, x->starter);

    writef(g, "~Mswitch (among_var) {~C~+"
              "~Mcase 0: ~f~N", p);

    p = p->left;
    if (p != 0 && p->type != c_literalstring) p = p->right;

    while (p) {
        if (p->type == c_bra && p->left != 0) {
            g->I[0] = case_number++;
            w(g, "~Mcase ~I0:~N~+"); generate(g, p); w(g, "~Mbreak;~N~-");
        }
        p = p->right;
    }
    w(g, "~}");
}

static void generate_booltest(struct generator * g, struct node * p) {

    g->V[0] = p->name;
    writef(g, "~Mif (!(~V0)) ~f~C", p);
}

static void generate_false(struct generator * g, struct node * p) {

    writef(g, "~M~f~C", p);
}

static void generate_debug(struct generator * g, struct node * p) {

    g->I[0] = g->debug_count++;
    g->I[1] = p->line_number;
    writef(g, "~Mdebug(~Z~I0, ~I1);~C", p);

}

static void generate(struct generator * g, struct node * p) {

    int used = g->label_used;
    int a0 = g->failure_label;
    int a1 = g->failure_keep_count;

    switch (p->type)
    {
        case c_define:        generate_define(g, p); break;
        case c_bra:           generate_bra(g, p); break;
        case c_and:           generate_and(g, p); break;
        case c_or:            generate_or(g, p); break;
        case c_backwards:     generate_backwards(g, p); break;
        case c_not:           generate_not(g, p); break;
        case c_set:           generate_set(g, p); break;
        case c_unset:         generate_unset(g, p); break;
        case c_try:           generate_try(g, p); break;
        case c_fail:          generate_fail(g, p); break;
        case c_reverse:
        case c_test:          generate_test(g, p); break;
        case c_do:            generate_do(g, p); break;
        case c_goto:          generate_GO(g, p, 1); break;
        case c_gopast:        generate_GO(g, p, 0); break;
        case c_repeat:        generate_repeat(g, p, false); break;
        case c_loop:          generate_loop(g, p); break;
        case c_atleast:       generate_atleast(g, p); break;
        case c_setmark:       generate_setmark(g, p); break;
        case c_tomark:        generate_tomark(g, p); break;
        case c_atmark:        generate_atmark(g, p); break;
        case c_hop:           generate_hop(g, p); break;
        case c_delete:        generate_delete(g, p); break;
        case c_next:          generate_next(g, p); break;
        case c_tolimit:       generate_tolimit(g, p); break;
        case c_atlimit:       generate_atlimit(g, p); break;
        case c_leftslice:     generate_leftslice(g, p); break;
        case c_rightslice:    generate_rightslice(g, p); break;
        case c_assignto:      generate_assignto(g, p); break;
        case c_sliceto:       generate_sliceto(g, p); break;
        case c_assign:        generate_assignfrom(g, p); break;
        case c_insert:
        case c_attach:        generate_insert(g, p, p->type); break;
        case c_slicefrom:     generate_slicefrom(g, p); break;
        case c_setlimit:      generate_setlimit(g, p); break;
        case c_dollar:        generate_dollar(g, p); break;
        case c_mathassign:    generate_integer_assign(g, p, "="); break;
        case c_plusassign:    generate_integer_assign(g, p, "+="); break;
        case c_minusassign:   generate_integer_assign(g, p, "-="); break;
        case c_multiplyassign:generate_integer_assign(g, p, "*="); break;
        case c_divideassign:  generate_integer_assign(g, p, "/="); break;
        case c_eq:            generate_integer_test(g, p, "=="); break;
        case c_ne:            generate_integer_test(g, p, "!="); break;
        case c_gr:            generate_integer_test(g, p, ">"); break;
        case c_ge:            generate_integer_test(g, p, ">="); break;
        case c_ls:            generate_integer_test(g, p, "<"); break;
        case c_le:            generate_integer_test(g, p, "<="); break;
        case c_call:          generate_call(g, p); break;
        case c_grouping:      generate_grouping(g, p, false); break;
        case c_non:           generate_grouping(g, p, true); break;
        case c_name:          generate_namedstring(g, p); break;
        case c_literalstring: generate_literalstring(g, p); break;
        case c_among:         generate_among(g, p); break;
        case c_substring:     generate_substring(g, p); break;
        case c_booltest:      generate_booltest(g, p); break;
        case c_false:         generate_false(g, p); break;
        case c_true:          break;
        case c_debug:         generate_debug(g, p); break;
        default: fprintf(stderr, "%d encountered\n", p->type);
                 exit(1);
    }

    if (g->failure_label != a0)
        g->label_used = used;
    g->failure_label = a0;
    g->failure_keep_count = a1;
}

static void generate_start_comment(struct generator * g) {

    if (g->options->make_lang == LANG_C)
        w(g, "/* This file was generated automatically by the Snowball to ISO C compiler */~N");
    else
        w(g, "/* This file was generated automatically by the Snowball to ISO C++ compiler */~N");
    w(g, "/* http://snowballstem.org/ */~N");
}

static void generate_head(struct generator * g) {

    if (g->options->make_lang != LANG_C) {
        const char * s = g->options->output_file;
        const char * leaf;
        w(g, "~N"
             "#include <config.h>~N"
             "#include <limits.h>~N");
        if (!s) abort(); /* checked in driver.c */
        leaf = strrchr(s, '/');
        if (leaf) ++leaf; else leaf = s;
        write_string(g, "#include \"");
        write_string(g, leaf);
        w(g, ".h\"~N~N");
        return;
    }

    if (g->options->runtime_path == 0) {
        w(g, "~N#include \"header.h\"~N~N");
    } else {
        w(g, "~N#include \"");
        write_string(g, g->options->runtime_path);
        if (g->options->runtime_path[strlen(g->options->runtime_path) - 1] != '/')
            write_char(g, '/');
        w(g, "header.h\"~N~N");
    }
}

static void generate_routine_headers(struct generator * g) {
    struct name * q;
    for (q = g->analyser->names; q; q = q->next) {
        g->V[0] = q;
        switch (q->type) {
            case t_routine:
                w(g, "static int ~W0(struct SN_env * z);~N");
                break;
            case t_external:
                w(g,
                  "#ifdef __cplusplus~N"
                  "extern \"C\" {~N"
                  "#endif~N"
                  "extern int ~W0(struct SN_env * z);~N"
                  "#ifdef __cplusplus~N"
                  "}~N"
                  "#endif~N"
                  );
                break;
        }
    }
}

static unsigned pool_size = 0;

static void generate_among_pool(struct generator * g, struct among * x) {

    while (x) {
        struct amongvec * v = x->b;
        int i;
        char * done = check_malloc(x->literalstring_count);
        memset(done, 0, x->literalstring_count);

        g->I[0] = x->number;

        for (i = 0; i < x->literalstring_count; i++, v++)
        {
            int j;
            if (v->size == 0 || done[i]) continue;
            g->I[1] = i;
            /* Eliminate entries which are just substrings of other entries */
            for (j = 0; j < x->literalstring_count; j++) {
                if (j == i) continue;
                if (v->size <= v[j - i].size) {
                    size_t offset = v[j - i].size - v->size;
                    size_t len = v->size * sizeof(symbol);
                    do {
                        if (memcmp(v->b, v[j - i].b + offset, len) == 0) {
                            g->I[2] = j;
                            if (offset) {
                                g->I[3] = offset;
                                w(g, "#define s_~I0_~I1 (s_~I0_~I2 + ~I3)~N");
                            } else {
                                w(g, "#define s_~I0_~I1 s_~I0_~I2~N");
                            }
                            goto done;
                        }
                    } while (offset--);
                }
            }
            if (v->size) {
                if (pool_size == 0) {
                    w(g, "static const symbol s_pool[] = {~N");
                }
                g->I[2] = pool_size;
                w(g, "#define s_~I0_~I1 ~I2~N");
                g->L[0] = v->b;
                w(g, "~A0,~N");
                pool_size += v->size;
            }
done: ;
        }

        check_free(done);
        x = x->next;
    }
    if (pool_size != 0) {
        w(g, "};~N~N");
    }
}

static void generate_among_table(struct generator * g, struct among * x) {

    struct amongvec * v = x->b;

    g->I[0] = x->number;
    g->I[1] = x->literalstring_count;
    w(g, "~N~Mstatic const struct among a_~I0[~I1] =~N{~N");

    {
        int i;
        for (i = 0; i < x->literalstring_count; i++) {
            g->I[1] = i;
            g->I[2] = v->size;
            g->I[3] = v->i;
            g->I[4] = v->result;
            g->S[0] = i < x->literalstring_count - 1 ? "," : "";

            w(g, "/*~J1 */ { ~I2, ");
            if (v->size == 0) w(g, "0,");
                         else w(g, "s_~I0_~I1,");
            w(g, " ~I3, ~I4");
            w(g, "}~S0~N");
            v++;
        }
    }
    w(g, "};~N~N");

    if (x->function_count) {
        g->I[1] = x->literalstring_count;
        w(g, "~Mstatic const unsigned char af_~I0[~I1] =~N{~N");

        v = x->b;
        {
            int i;
            for (i = 0; i < x->literalstring_count; i++) {
                g->I[1] = i;

                w(g, "/*~J1 */ ");
                if (v[i].function == 0) {
                    w(g, "0");
                } else {
                    write_int(g, v[i].function->among_func_count);
                    g->V[0] = v[i].function;
                    w(g, " /* t~W0 */");
                }
                if (i < x->literalstring_count - 1) w(g, ",~N");
            }
        }
        w(g, "~N};~N~N");
    }
}

static void generate_amongs(struct generator * g) {
    struct among * x;
    struct name * q;
    int among_func_count = 0;

    g->S[0] = g->options->name;
    for (q = g->analyser->names; q; q = q->next) {
        if (q->type == t_routine && q->used_in_among) {
            q->among_func_count = ++among_func_count;
            g->V[0] = q;
            w(g, "static int t~V0(Xapian::StemImplementation * this_ptr) {~N"
                 "    return (static_cast<Xapian::~S0 *>(this_ptr))->~V0();~N"
                 "}~N"
                 "~N");
        }
    }

    if (among_func_count) {
        g->I[0] = among_func_count;
        w(g, "~Mstatic const among_function af[~I0] =~N{~N");

        q = g->analyser->names;
        g->S[0] = g->options->name;
        for (q = g->analyser->names; q; q = q->next) {
            if (q->type == t_routine && q->used_in_among) {
                g->V[0] = q;
                g->I[0] = q->among_func_count;
                w(g, "/*~J0 */ t~V0");
                if (q->among_func_count < among_func_count) w(g, ",~N"); else w(g, "~N");
            }
        }

        w(g, "};~N~N");
    }

    generate_among_pool(g, g->analyser->amongs);

    for (x = g->analyser->amongs; x; x = x->next) {
        generate_among_table(g, x);
    }
}

static void set_bit(symbol * b, int i) { b[i/8] |= 1 << i%8; }

static void generate_grouping_table(struct generator * g, struct grouping * q) {

    int range = q->largest_ch - q->smallest_ch + 1;
    int size = (range + 7)/ 8;  /* assume 8 bits per symbol */
    symbol * b = q->b;
    symbol * map = create_b(size);
    int i;
    for (i = 0; i < size; i++) map[i] = 0;

    for (i = 0; i < SIZE(b); i++) set_bit(map, b[i] - q->smallest_ch);

    g->V[0] = q->name;

    w(g, "static const unsigned char ~V0[] = { ");
    for (i = 0; i < size; i++) {
        write_int(g, map[i]);
        if (i < size - 1) w(g, ", ");
    }
    w(g, " };~N~N");
    lose_b(map);
}

static void generate_groupings(struct generator * g) {
    struct grouping * q;
    for (q = g->analyser->groupings; q; q = q->next) {
        generate_grouping_table(g, q);
    }
}

static void generate_create(struct generator * g) {

    int * p = g->analyser->name_count;

    if (g->options->make_lang != LANG_C) {
        struct name * q = g->analyser->names;
        int first = true;
        const char * dtor;
        g->S[0] = g->options->name;
        dtor = strrchr(g->options->name, ':');
        if (dtor) ++dtor; else dtor = g->options->name;
        g->S[1] = dtor;
        w(g, "~N"
             "Xapian::~S0::~S1()");
        while (q) {
            if (q->type < t_routine) {
                w(g, first ? "~N    : " : ", ");
                first = false;
                g->V[0] = q;
                w(g, "~W0(0)");
            }
            q = q->next;
        }
        w(g, "~N{~N");
        q = g->analyser->names;
        while (q) {
            if (q->type == t_string) {
                g->V[0] = q;
                w(g, "    ~W0 = create_s();~N");
            }
            q = q->next;
        }
        w(g, "}~N");

        return;
    }

    g->I[0] = p[t_string];
    g->I[1] = p[t_integer];
    g->I[2] = p[t_boolean];
    w(g, "~N"
         "extern struct SN_env * ~pcreate_env(void) { return SN_create_env(~I0, ~I1, ~I2); }"
         "~N");
}

static void generate_close(struct generator * g) {

    int * p = g->analyser->name_count;
    if (g->options->make_lang != LANG_C) {
        struct name * q = g->analyser->names;
        const char * dtor;
        const char * lang;
        g->S[0] = g->options->name;
        dtor = strrchr(g->options->name, ':');
        if (dtor) ++dtor; else dtor = g->options->name;
        g->S[1] = dtor;
        lang = strrchr(g->options->output_file, '/');
        if (lang) ++lang; else lang = g->options->output_file;
        g->S[2] = lang;
        w(g, "~N"
             "Xapian::~S0::~~~S1()~N"
             "{~N");
        while (q) {
            if (q->type == t_string) {
                g->V[0] = q;
                w(g, "    lose_s(~W0);~N");
            }
            q = q->next;
        }
        w(g, "}~N");

        w(g, "~N"
             "std::string~N"
             "Xapian::~S0::get_description() const~N"
             "{~N"
             "    return \"~S2\";~N"
             "}~N");
        return;
    }

    g->I[0] = p[t_string];
    w(g, "~Nextern void ~pclose_env(struct SN_env * z) { SN_close_env(z, ~I0); }~N~N");
}

static void generate_create_and_close_templates(struct generator * g) {
    w(g, "~N"
         "extern struct SN_env * ~pcreate_env(void);~N"
         "extern void ~pclose_env(struct SN_env * z);~N"
         "~N");
}

static void generate_header_file(struct generator * g) {

    struct name * q;
    const char * vp = g->options->variables_prefix;
    g->S[0] = vp;

    if (g->options->make_lang != LANG_C) {
        const char * p;
        w(g, "~N"
             "#include \"steminternal.h\"~N"
             "~N"
             "namespace Xapian {~N"
             "~N");

        g->S[1] = g->options->name;
        w(g, "class ~S1 ");
        if (g->options->parent_class_name) {
            g->S[1] = g->options->parent_class_name;
            w(g, ": public ~S1 ");
        }
        w(g, "{~N");
        for (q = g->analyser->names; q; q = q->next) {
            switch (q->type) {
                case t_string:  g->S[1] = "symbol *"; goto label1;
                case t_integer: g->S[1] = "int"; goto label1;
                case t_boolean: g->S[1] = "unsigned char";
                label1:
                    g->V[0] = q;
                    w(g, "    ~S1 ~W0;~N");
                    break;
             }
        }

        for (q = g->analyser->names; q; q = q->next) {
            if (q->type == t_routine && !q->used_in_among) {
                g->V[0] = q;
                w(g, "    int ~W0();~N");
            }
        }

        w(g, "~N  public:~N");

        /* FIXME: We currently need to make any routines used in an among
         * public. */
        for (q = g->analyser->names; q; q = q->next) {
            if (q->type == t_routine && q->used_in_among) {
                g->V[0] = q;
                w(g, "    int ~W0();~N");
            }
        }

        w(g, "~N");
        p = strrchr(g->options->name, ':');
        if (p) ++p; else p = g->options->name;
        g->S[1] = p;
        w(g, "    ~S1();~N"
             "    ~~~S1();~N");
        for (q = g->analyser->names; q; q = q->next) {
            if (q->type == t_external) {
                g->V[0] = q;
                w(g, "    int ~W0();~N");
            }
        }

        w(g, "    std::string get_description() const;~N"
             "};~N"
             "~N"
             "}~N");

        return;
    }

    w(g, "~N"
         "#ifdef __cplusplus~N"
         "extern \"C\" {~N"
         "#endif~N");            /* for C++ */

    generate_create_and_close_templates(g);
    for (q = g->analyser->names; q; q = q->next) {
        g->V[0] = q;
        switch (q->type) {
            case t_external:
                w(g, "extern int ~W0(struct SN_env * z);~N");
                break;
            case t_string:  g->S[1] = "S"; goto label0;
            case t_integer: g->S[1] = "I"; goto label0;
            case t_boolean: g->S[1] = "B";
            label0:
                if (vp) {
                    g->I[0] = q->count;
                    w(g, "#define ~S0");
                    str_append_b(g->outbuf, q->b);
                    w(g, " (~S1[~I0])~N");
                }
                break;
        }
    }

    w(g, "~N"
         "#ifdef __cplusplus~N"
         "}~N"
         "#endif~N");            /* for C++ */

    w(g, "~N");
}

extern void generate_program_c(struct generator * g) {

    g->outbuf = str_new();
    generate_start_comment(g);
    generate_head(g);
    if (g->options->make_lang == LANG_C) {
        generate_routine_headers(g);
        w(g, "#ifdef __cplusplus~N"
             "extern \"C\" {~N"
             "#endif~N"
             "~N");
        generate_create_and_close_templates(g);
        w(g, "~N"
             "#ifdef __cplusplus~N"
             "}~N"
             "#endif~N");
    }
    generate_amongs(g);
    generate_groupings(g);
    g->declarations = g->outbuf;
    g->outbuf = str_new();
    g->literalstring_count = 0;
    {
        struct node * p = g->analyser->program;
        while (p) { generate(g, p); p = p->right; }
    }
    generate_create(g);
    generate_close(g);
    output_str(g->options->output_src, g->declarations);
    str_delete(g->declarations);
    output_str(g->options->output_src, g->outbuf);
    str_clear(g->outbuf);

    generate_start_comment(g);
    generate_header_file(g);
    output_str(g->options->output_h, g->outbuf);
    str_delete(g->outbuf);
}

/* Generator functions common to multiple languages. */

extern struct generator * create_generator(struct analyser * a, struct options * o) {
    NEW(generator, g);
    g->analyser = a;
    g->options = o;
    g->margin = 0;
    g->debug_count = 0;
    g->copy_from_count = 0;
    g->line_count = 0;
    g->line_labelled = 0;
    g->failure_label = -1;
    g->unreachable = false;
#ifndef DISABLE_PYTHON
    g->max_label = 0;
#endif
    return g;
}

extern void close_generator(struct generator * g) {
    FREE(g);
}

/* Write routines for simple entities */

extern void write_char(struct generator * g, int ch) {
    str_append_ch(g->outbuf, ch); /* character */
}

extern void write_newline(struct generator * g) {
    str_append_ch(g->outbuf, '\n'); /* newline */
    g->line_count++;
}

extern void write_string(struct generator * g, const char * s) {
    str_append_string(g->outbuf, s);
}

extern void write_int(struct generator * g, int i) {
    str_append_int(g->outbuf, i);
}

extern void write_b(struct generator * g, symbol * b) {

    str_append_b(g->outbuf, b);
}

extern void write_str(struct generator * g, struct str * str) {

    str_append(g->outbuf, str);
}