roff.h

   1 /*
   2  * Most functions and variables in neatroff are prefixed with tokens
   3  * that indicate their purpose, such as:
   4  *
   5  * + tr_xyz: the implementation of troff request .xyz (mostly tr.c)
   6  * + in_xyz: input layer (in.c)
   7  * + cp_xyz: copy-mode interpretation layer (cp.c)
   8  * + ren_xyz: rendering characters into lines (ren.c)
   9  * + out_xyz: output layer for generating troff output (out.c)
  10  * + dev_xyz: output devices (dev.c)
  11  * + num_xyz: number registers (reg.c)
  12  * + str_xyz: string registers (reg.c)
  13  * + env_xyz: environments (reg.c)
  14  * + eval_xyz: integer expression evaluation (eval.c)
  15  * + font_xyz: fonts (font.c)
  16  * + sbuf_xyz: variable length string buffers (sbuf.c)
  17  * + dict_xyz: dictionaries (dict.c)
  18  * + wb_xyz: word buffers (wb.c)
  19  * + fmt_xyz: line formatting buffers (fmt.c)
  20  * + n_xyz: builtin number register xyz
  21  * + c_xyz: characters for requests like hc and mc
  22  *
  23  */
  24
  25 /* predefined array limits */
  26 #define PATHLEN         1024    /* path length */
  27 #define NFILES          16      /* number of input files */
  28 #define NFONTS          32      /* number of fonts */
  29 #define NGLYPHS         1024    /* glyphs in fonts */
  30 #define NLIGS           128     /* number of font ligatures */
  31 #define NKERNS          1024    /* number of font kerning pairs */
  32 #define FNLEN           32      /* font name length */
  33 #define NMLEN           32      /* macro/register/environment/glyph name length */
  34 #define GNLEN           NMLEN   /* glyph name length */
  35 #define RNLEN           NMLEN   /* register/macro name */
  36 #define ILNLEN          1000    /* line limit of input files */
  37 #define LNLEN           4000    /* line buffer length (ren.c/out.c) */
  38 #define NWORDS          1024    /* number of queued words in formatting buffer */
  39 #define NLINES          32      /* number of queued lines in formatting buffer */
  40 #define NARGS           16      /* number of macro arguments */
  41 #define NPREV           16      /* environment stack depth */
  42 #define NTRAPS          1024    /* number of traps per page */
  43 #define NIES            128     /* number of nested .ie commands */
  44 #define NTABS           16      /* number of tab stops */
  45 #define NCMAPS          512     /* number of character translations (.tr) */
  46 #define NSSTR           32      /* number of nested sstr_push() calls */
  47 #define NFIELDS         32      /* number of fields */
  48 #define MAXFRAC         100000  /* maximum value of the fractional part */
  49 #define LIGLEN          4       /* length of ligatures */
  50 #define NCDEFS          128     /* number of character definitions (.char) */
  51 #define NHYPHS          16384   /* hyphenation dictionary/patterns (.hw) */
  52 #define NHYPHSWORD      16      /* number of hyphenations per word */
  53 #define NHCODES         512     /* number of .hcode characters */
  54 #define WORDLEN         256     /* word length (for hyph.c) */
  55
  56 /* converting scales */
  57 #define SC_IN           (dev_res)       /* inch in units */
  58 #define SC_PT           (SC_IN / 72)    /* point in units */
  59 #define SC_EM           (n_s * SC_IN / 72)
  60
  61 /* escape sequences */
  62 #define ESC_Q   "bCDhHlLNoRSvwxX?"      /* \X'ccc' quoted escape sequences */
  63 #define ESC_P   "*fgkmns"               /* \Xc \X(cc \X[ccc] escape sequences */
  64
  65 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
  66 #define MAX(a, b)       ((a) < (b) ? (b) : (a))
  67 #define LEN(a)          (sizeof(a) / sizeof((a)[0]))
  68
  69 /* special characters */
  70 extern int c_ec;        /* escape character (\) */
  71 extern int c_cc;        /* basic control character (.) */
  72 extern int c_c2;        /* no-break control character (') */
  73 #define c_ni    4       /* non-interpreted copy-mode escape */
  74 #define c_hc    env_hc()/* hyphenation character */
  75 #define c_mc    env_mc()/* margin character (.mc) */
  76 #define c_tc    env_tc()
  77 #define c_lc    env_lc()
  78 #define c_bp    "\\:"   /* zero-width word break point */
  79
  80 /* number registers */
  81 int num_get(int id, int inc);
  82 void num_set(int id, int val);
  83 void num_inc(int id, int val);
  84 void num_del(int id);
  85 char *num_str(int id);
  86 char *num_getfmt(int id);
  87 void num_setfmt(int id, char *fmt);
  88 int *nreg(int id);
  89 int eval(char *s, int unit);
  90 int eval_up(char **s, int unit);
  91 int eval_re(char *s, int orig, int unit);
  92
  93 /* string registers */
  94 void str_set(int id, char *s);
  95 void str_dset(int id, void *d);
  96 char *str_get(int id);
  97 void *str_dget(int id);
  98 void str_rm(int id);
  99 void str_rn(int src, int dst);
 100
 101 /* saving and restoring registers before and after printing diverted lines */
 102 void odiv_beg(void);
 103 void odiv_end(void);
 104
 105 /* enviroments */
 106 void env_init(void);
 107 void env_done(void);
 108 struct fmt *env_fmt(void);
 109 struct wb *env_wb(void);
 110 char *env_hc(void);
 111 char *env_mc(void);
 112 char *env_tc(void);
 113 char *env_lc(void);
 114 int tab_next(int pos);
 115 int tab_type(int pos);
 116
 117 /* dictionary */
 118 struct dict {
 119         int *head;
 120         char **key;
 121         long *val;
 122         int *next;
 123         int size;
 124         int n;
 125         char *buf;              /* buffer for keys */
 126         int buflen;
 127         int level2;             /* use two characters for hashing */
 128         long notfound;          /* the value returned for missing keys */
 129 };
 130
 131 void dict_init(struct dict *d, int size, long notfound, int dupkeys, int level2);
 132 void dict_done(struct dict *d);
 133 void dict_put(struct dict *d, char *key, long val);
 134 long dict_get(struct dict *d, char *key);
 135 long dict_pop(struct dict *d, char *key);
 136 int dict_idx(struct dict *d, char *key);
 137 char *dict_key(struct dict *d, int idx);
 138 long dict_val(struct dict *d, int idx);
 139 long dict_prefix(struct dict *d, char *key, int *idx);
 140
 141 /* device related variables */
 142 extern int dev_res;
 143 extern int dev_uwid;
 144 extern int dev_hor;
 145 extern int dev_ver;
 146
 147 struct glyph {
 148         char id[GNLEN];         /* device-dependent glyph identifier */
 149         char name[GNLEN];       /* the first character mapped to this glyph */
 150         struct font *font;      /* glyph font */
 151         int wid;                /* character width */
 152         int type;               /* character type; ascender/descender */
 153         int llx, lly, urx, ury; /* character bounding box */
 154 };
 155
 156 struct font {
 157         char name[FNLEN];
 158         char fontname[FNLEN];
 159         struct glyph glyphs[NGLYPHS];
 160         int nglyphs;
 161         int spacewid;
 162         int special;
 163         int cs, bd;                     /* for .cs and .bd requests */
 164         struct dict gdict;              /* mapping from glyphs[i].id to i */
 165         /* charset section characters */
 166         char c[NGLYPHS][GNLEN];         /* character names in charset */
 167         struct glyph *g[NGLYPHS];       /* character glyphs in charset */
 168         struct glyph *g_map[NGLYPHS];   /* character remapped via font_map() */
 169         int n;                          /* number of characters in charset */
 170         struct dict cdict;              /* mapping from c[i] to i */
 171         /* font ligatures (lg*) */
 172         char lg[NLIGS][LIGLEN * GNLEN]; /* ligatures */
 173         int lgn;                        /* number of ligatures in lg[] */
 174         /* kerning pair table per glyph (kn*) */
 175         int knhead[NGLYPHS];            /* kerning pairs of glyphs[] */
 176         int knnext[NKERNS];             /* next item in knhead[] list */
 177         int knpair[NKERNS];             /* kerning pair 2nd glyphs */
 178         int knval[NKERNS];              /* font pairwise kerning value */
 179         int knn;                        /* number of kerning pairs */
 180 };
 181
 182 /* output device functions */
 183 int dev_open(char *dir, char *dev);
 184 void dev_close(void);
 185 int dev_mnt(int pos, char *id, char *name);
 186 int dev_pos(char *id);
 187 struct font *dev_font(int pos);
 188 int dev_fontpos(struct font *fn);
 189 void dev_setcs(int fn, int cs);
 190 int dev_getcs(int fn);
 191 void dev_setbd(int fn, int bd);
 192 int dev_getbd(int fn);
 193
 194 /* font-related functions */
 195 struct font *font_open(char *path);
 196 void font_close(struct font *fn);
 197 struct glyph *font_glyph(struct font *fn, char *id);
 198 struct glyph *font_find(struct font *fn, char *name);
 199 int font_lig(struct font *fn, char **c, int n);
 200 int font_kern(struct font *fn, char *c1, char *c2);
 201 int font_islig(struct font *fn, char *s);
 202 int font_map(struct font *fn, char *name, struct glyph *gl);
 203 int font_mapped(struct font *fn, char *name);
 204
 205 /* glyph handling functions */
 206 struct glyph *dev_glyph(char *c, int fn);
 207 int charwid(int fn, int sz, int wid);
 208
 209 /* convert wid in device unitwidth size to size sz */
 210 #define DEVWID(sz, wid)         (((wid) * (sz) + (dev_uwid / 2)) / dev_uwid)
 211 /* the amount of word and sentence space for the given font and size */
 212 #define N_SS(fn, sz)    (charwid((fn), (sz), (dev_font(fn)->spacewid * n_ss + 6) / 12))
 213 #define N_SSS(fn, sz)   (charwid((fn), (sz), (dev_font(fn)->spacewid * n_sss + 6) / 12))
 214
 215 /* different layers of neatroff */
 216 int in_next(void);              /* input layer */
 217 int cp_next(void);              /* copy-mode layer */
 218 int tr_next(void);              /* troff layer */
 219
 220 void in_push(char *s, char **args);
 221 void in_so(char *path);         /* .so request */
 222 void in_nx(char *path);         /* .nx request */
 223 void in_ex(void);               /* .ex request */
 224 void in_lf(char *path, int ln); /* .lf request */
 225 void in_queue(char *path);      /* queue the given input file */
 226 char *in_arg(int i);            /* look up argument */
 227 int in_nargs(void);             /* number of arguments */
 228 void in_back(int c);            /* push back input character */
 229 int in_top(void);               /* the first pushed-back character */
 230 char *in_filename(void);        /* current filename */
 231 int in_lnum(void);              /* current line number */
 232
 233 void cp_blk(int skip);          /* skip or read the next line or block */
 234 void cp_copymode(int mode);     /* do not interpret \w and \E */
 235 #define cp_back         in_back /* cp.c is stateless */
 236 int tr_nextreq(void);           /* read the next troff request */
 237
 238 /* variable length string buffer */
 239 struct sbuf {
 240         char *s;                /* allocated buffer */
 241         int sz;                 /* buffer size */
 242         int n;                  /* length of the string stored in s */
 243 };
 244
 245 void sbuf_init(struct sbuf *sbuf);
 246 void sbuf_done(struct sbuf *sbuf);
 247 char *sbuf_buf(struct sbuf *sbuf);
 248 void sbuf_add(struct sbuf *sbuf, int c);
 249 void sbuf_append(struct sbuf *sbuf, char *s);
 250 void sbuf_printf(struct sbuf *sbuf, char *s, ...);
 251 void sbuf_putnl(struct sbuf *sbuf);
 252 void sbuf_cut(struct sbuf *sbuf, int n);
 253 int sbuf_len(struct sbuf *sbuf);
 254 int sbuf_empty(struct sbuf *sbuf);
 255
 256 /* word buffer */
 257 struct wb {
 258         struct sbuf sbuf;
 259         int f, s, m;            /* the last output font and size */
 260         int r_f, r_s, r_m;      /* current font and size; use n_f and n_s if -1 */
 261         int part;               /* partial input (\c) */
 262         int els_neg, els_pos;   /* extra line spacing */
 263         int h, v;               /* buffer vertical and horizontal positions */
 264         int ct, sb, st;         /* \w registers */
 265         int llx, lly, urx, ury; /* bounding box */
 266         int icleft_ll;          /* len after the pending left italic correction */
 267         /* saving previous characters added via wb_put() */
 268         char prev_c[LIGLEN][GNLEN];
 269         int prev_l[LIGLEN];     /* sbuf_len(&wb->sbuf) before wb_put() calls */
 270         int prev_h[LIGLEN];     /* wb->h before wb_put() calls */
 271         int prev_n;             /* number of characters in prev_c[] */
 272         int prev_ll;            /* sbuf_len(&wb->sbuf) after the last wb_put() */
 273 };
 274
 275 void wb_init(struct wb *wb);
 276 void wb_done(struct wb *wb);
 277 void wb_hmov(struct wb *wb, int n);
 278 void wb_vmov(struct wb *wb, int n);
 279 void wb_els(struct wb *wb, int els);
 280 void wb_etc(struct wb *wb, char *x);
 281 void wb_put(struct wb *wb, char *c);
 282 void wb_putexpand(struct wb *wb, char *c);
 283 int wb_part(struct wb *wb);
 284 void wb_setpart(struct wb *wb);
 285 void wb_drawl(struct wb *wb, int c, int h, int v);
 286 void wb_drawc(struct wb *wb, int c, int r);
 287 void wb_drawe(struct wb *wb, int c, int h, int v);
 288 void wb_drawa(struct wb *wb, int c, int h1, int v1, int h2, int v2);
 289 void wb_drawxbeg(struct wb *wb, int c);
 290 void wb_drawxdot(struct wb *wb, int h, int v);
 291 void wb_drawxend(struct wb *wb);
 292 void wb_italiccorrection(struct wb *wb);
 293 void wb_italiccorrectionleft(struct wb *wb);
 294 void wb_cat(struct wb *wb, struct wb *src);
 295 void wb_catstr(struct wb *wb, char *beg, char *end);
 296 int wb_hyphmark(char *word, int *hyidx, int *hyins);
 297 int wb_hyph(char *word, int *hyidx, int flg);
 298 int wb_wid(struct wb *wb);
 299 int wb_dashwid(struct wb *wb);
 300 int wb_empty(struct wb *wb);
 301 int wb_eos(struct wb *wb);
 302 void wb_wconf(struct wb *wb, int *ct, int *st, int *sb,
 303                 int *llx, int *lly, int *urx, int *ury);
 304 int wb_lig(struct wb *wb, char *c);
 305 int wb_kern(struct wb *wb, char *c);
 306 void wb_reset(struct wb *wb);
 307 char *wb_buf(struct wb *wb);
 308 void wb_fnszget(struct wb *wb, int *fn, int *sz, int *m);
 309 void wb_fnszset(struct wb *wb, int fn, int sz, int m);
 310
 311 /* character translation (.tr) */
 312 void cmap_add(char *c1, char *c2);
 313 char *cmap_map(char *c);
 314 /* character definition (.char) */
 315 char *cdef_map(char *c, int fn);
 316 int cdef_expand(struct wb *wb, char *c, int fn);
 317
 318 /* hyphenation flags */
 319 #define HY_LAST         0x02    /* do not hyphenate last lines */
 320 #define HY_FINAL2       0x04    /* do not hyphenate the final two characters */
 321 #define HY_FIRST2       0x08    /* do not hyphenate the first two characters */
 322
 323 void hyphenate(char *hyphs, char *word, int flg);
 324 void hyph_init(void);
 325
 326 /* adjustment types */
 327 #define AD_C            0       /* center */
 328 #define AD_L            1       /* adjust left margin (flag) */
 329 #define AD_R            2       /* adjust right margin (flag) */
 330 #define AD_B            3       /* adjust both margin (mask) */
 331 #define AD_P            4       /* paragraph-at-once adjustment (flag) */
 332
 333 /* line formatting */
 334 struct fmt *fmt_alloc(void);
 335 void fmt_free(struct fmt *fmt);
 336 int fmt_wid(struct fmt *fmt);
 337 void fmt_space(struct fmt *fmt);
 338 void fmt_suppressnl(struct fmt *fmt);
 339 int fmt_word(struct fmt *fmt, struct wb *wb);
 340 int fmt_newline(struct fmt *fmt);
 341 int fmt_fillreq(struct fmt *f);
 342 int fmt_br(struct fmt *fmt);
 343 int fmt_fill(struct fmt *fmt);
 344 int fmt_morelines(struct fmt *fmt);
 345 int fmt_morewords(struct fmt *fmt);
 346 int fmt_nextline(struct fmt *fmt, struct sbuf *sbuf, int *w,
 347                 int *li, int *ll, int *els_neg, int *els_pos);
 348
 349 /* rendering */
 350 int render(void);                               /* the main loop */
 351 int ren_parse(struct wb *wb, char *c);
 352 int ren_char(struct wb *wb, int (*next)(void), void (*back)(int));
 353 int ren_wid(int (*next)(void), void (*back)(int));
 354 void ren_tl(int (*next)(void), void (*back)(int));
 355 void ren_hline(struct wb *wb, int l, char *c);  /* horizontal line */
 356 void ren_hlcmd(struct wb *wb, char *arg);       /* \l */
 357 void ren_vlcmd(struct wb *wb, char *arg);       /* \L */
 358 void ren_bcmd(struct wb *wb, char *arg);        /* \b */
 359 void ren_ocmd(struct wb *wb, char *arg);        /* \o */
 360 void ren_dcmd(struct wb *wb, char *arg);        /* \D */
 361
 362 /* out.c */
 363 void out_line(char *s);                         /* output rendered line */
 364 void out(char *s, ...);                         /* output troff cmd */
 365
 366 /* troff commands */
 367 void tr_ab(char **args);
 368 void tr_bp(char **args);
 369 void tr_br(char **args);
 370 void tr_ce(char **args);
 371 void tr_ch(char **args);
 372 void tr_cl(char **args);
 373 void tr_di(char **args);
 374 void tr_divbeg(char **args);
 375 void tr_divend(char **args);
 376 void tr_dt(char **args);
 377 void tr_em(char **args);
 378 void tr_ev(char **args);
 379 void tr_fc(char **args);
 380 void tr_fi(char **args);
 381 void tr_fp(char **args);
 382 void tr_fspecial(char **args);
 383 void tr_ft(char **args);
 384 void tr_hcode(char **args);
 385 void tr_hpf(char **args);
 386 void tr_hpfa(char **args);
 387 void tr_hw(char **args);
 388 void tr_in(char **args);
 389 void tr_ll(char **args);
 390 void tr_mk(char **args);
 391 void tr_ne(char **args);
 392 void tr_nf(char **args);
 393 void tr_ns(char **args);
 394 void tr_os(char **args);
 395 void tr_pn(char **args);
 396 void tr_ps(char **args);
 397 void tr_rs(char **args);
 398 void tr_rt(char **args);
 399 void tr_sp(char **args);
 400 void tr_sv(char **args);
 401 void tr_ta(char **args);
 402 void tr_ti(char **args);
 403 void tr_wh(char **args);
 404 void tr_popren(char **args);
 405
 406 void tr_init(void);
 407 int tr_readargs(char **args, struct sbuf *sbuf,
 408                 int (*next)(void), void (*back)(int));
 409
 410 /* helpers */
 411 void errmsg(char *msg, ...);
 412 void errdie(char *msg);
 413 void *xmalloc(long len);
 414 int utf8len(int c);
 415 int utf8next(char *s, int (*next)(void));
 416 int utf8read(char **s, char *d);
 417 int utf8one(char *s);
 418 int charnext(char *c, int (*next)(void), void (*back)(int));
 419 int charread(char **s, char *c);
 420 int charnext_delim(char *c, int (*next)(void), void (*back)(int), char *delim);
 421 int charread_delim(char **s, char *c, char *delim);
 422 void charnext_str(char *d, char *c);
 423 void argnext(char *d, int cmd, int (*next)(void), void (*back)(int));
 424 void argread(char **sp, char *d, int cmd);
 425 int escread(char **s, char *d);
 426 /* string streams; nested next()/back() interface for string buffers */
 427 void sstr_push(char *s);
 428 char *sstr_pop(void);
 429 int sstr_next(void);
 430 void sstr_back(int c);
 431
 432 /* internal commands */
 433 #define TR_DIVBEG       "\07<"  /* diversion begins */
 434 #define TR_DIVEND       "\07>"  /* diversion ends */
 435 #define TR_POPREN       "\07P"  /* exit render_rec() */
 436
 437 /* mapping register, macro and environment names to indices */
 438 #define NREGS           4096    /* maximum number of mapped names */
 439 #define DOTMAP(c2)      (c2)    /* optimized mapping for ".x" names */
 440
 441 int map(char *s);               /* map name s to an index */
 442 char *map_name(int id);         /* return the name mapped to id */
 443
 444 /* colors */
 445 #define CLR_R(c)                (((c) >> 16) & 0xff)
 446 #define CLR_G(c)                (((c) >> 8) & 0xff)
 447 #define CLR_B(c)                ((c) & 0xff)
 448 #define CLR_RGB(r, g, b)        (((r) << 16) | ((g) << 8) | (b))
 449
 450 char *clr_str(int c);
 451 int clr_get(char *s);
 452
 453 /* builtin number registers; n_X for .X register */
 454 #define n_a             (*nreg(DOTMAP('a')))
 455 #define n_cp            (*nreg(DOTMAP('C')))
 456 #define n_d             (*nreg(DOTMAP('d')))
 457 #define n_f             (*nreg(DOTMAP('f')))
 458 #define n_h             (*nreg(DOTMAP('h')))
 459 #define n_i             (*nreg(DOTMAP('i')))
 460 #define n_it            (*nreg(map(".it")))     /* .it trap macro */
 461 #define n_itn           (*nreg(map(".itn")))    /* .it lines left */
 462 #define n_j             (*nreg(DOTMAP('j')))
 463 #define n_l             (*nreg(DOTMAP('l')))
 464 #define n_L             (*nreg(DOTMAP('L')))
 465 #define n_n             (*nreg(DOTMAP('n')))
 466 #define n_nI            (*nreg(map(".nI")))     /* i for .nm */
 467 #define n_nm            (*nreg(map(".nm")))     /* .nm enabled */
 468 #define n_nM            (*nreg(map(".nM")))     /* m for .nm */
 469 #define n_nn            (*nreg(map(".nn")))     /* remaining .nn */
 470 #define n_nS            (*nreg(map(".nS")))     /* s for .nm */
 471 #define n_m             (*nreg(DOTMAP('m')))
 472 #define n_mc            (*nreg(map(".mc")))     /* .mc enabled */
 473 #define n_mcn           (*nreg(map(".mcn")))    /* .mc distance */
 474 #define n_o             (*nreg(DOTMAP('o')))
 475 #define n_p             (*nreg(DOTMAP('p')))
 476 #define n_s             (*nreg(DOTMAP('s')))
 477 #define n_u             (*nreg(DOTMAP('u')))
 478 #define n_v             (*nreg(DOTMAP('v')))
 479 #define n_ct            (*nreg(map("ct")))
 480 #define n_dl            (*nreg(map("dl")))
 481 #define n_dn            (*nreg(map("dn")))
 482 #define n_ln            (*nreg(map("ln")))
 483 #define n_nl            (*nreg(map("nl")))
 484 #define n_sb            (*nreg(map("sb")))
 485 #define n_st            (*nreg(map("st")))
 486 #define n_pg            (*nreg(map("%")))       /* % */
 487 #define n_lb            (*nreg(map(".b0")))     /* input line beg */
 488 #define n_ce            (*nreg(map(".ce")))     /* .ce remaining */
 489 #define n_f0            (*nreg(map(".f0")))     /* last .f */
 490 #define n_lg            (*nreg(map(".lg")))     /* .lg mode */
 491 #define n_hy            (*nreg(map(".hy")))     /* .hy mode */
 492 #define n_hyp           (*nreg(map(".hyp")))    /* hyphenation penalty  */
 493 #define n_i0            (*nreg(map(".i0")))     /* last .i */
 494 #define n_ti            (*nreg(map(".ti")))     /* pending .ti */
 495 #define n_kn            (*nreg(map(".kern")))   /* .kn mode */
 496 #define n_l0            (*nreg(map(".l0")))     /* last .l */
 497 #define n_L0            (*nreg(map(".L0")))     /* last .L */
 498 #define n_m0            (*nreg(map(".m0")))     /* last .m */
 499 #define n_mk            (*nreg(map(".mk")))     /* .mk internal register */
 500 #define n_na            (*nreg(map(".na")))     /* .na mode */
 501 #define n_ns            (*nreg(map(".ns")))     /* .ns mode */
 502 #define n_o0            (*nreg(map(".o0")))     /* last .o */
 503 #define n_ss            (*nreg(map(".ss")))     /* word space (.ss) */
 504 #define n_sss           (*nreg(map(".sss")))    /* sentence space (.ss) */
 505 #define n_ssh           (*nreg(map(".ssh")))    /* word space compression (.ssh) */
 506 #define n_s0            (*nreg(map(".s0")))     /* last .s */
 507 #define n_sv            (*nreg(map(".sv")))     /* .sv value */
 508 #define n_lt            (*nreg(map(".lt")))     /* .lt value */
 509 #define n_t0            (*nreg(map(".lt0")))    /* previous .lt value */
 510 #define n_v0            (*nreg(map(".v0")))     /* last .v */
 511 #define n_llx           (*nreg(map("bbllx")))   /* \w bounding box */
 512 #define n_lly           (*nreg(map("bblly")))   /* \w bounding box */
 513 #define n_urx           (*nreg(map("bburx")))   /* \w bounding box */
 514 #define n_ury           (*nreg(map("bbury")))   /* \w bounding box */
 515
 516 /* functions for implementing read-only registers */
 517 int f_nexttrap(void);   /* .t */
 518 int f_divreg(void);     /* .z */
 519 int f_hpos(void);       /* .k */