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 FNLEN           32      /* font name length */
  30 #define GNLEN           32      /* glyph name length */
  31 #define NMLEN           128     /* macro/register/environment name length */
  32 #define RNLEN           NMLEN   /* register/macro name */
  33 #define NREGS           8192    /* number of mapped names */
  34 #define ILNLEN          1000    /* line limit of input files */
  35 #define NARGS           16      /* number of macro arguments */
  36 #define NPREV           16      /* environment stack depth */
  37 #define NTRAPS          1024    /* number of traps per page */
  38 #define NIES            128     /* number of nested .ie commands */
  39 #define NTABS           16      /* number of tab stops */
  40 #define NCMAPS          512     /* number of character translations (.tr) */
  41 #define NSSTR           32      /* number of nested sstr_push() calls */
  42 #define NFIELDS         32      /* number of fields */
  43 #define NCHARS          32      /* number of characters for .eos, .hydash, .hystop */
  44 #define MAXFRAC         100000  /* maximum value of the fractional part */
  45 #define NCDEFS          128     /* number of character definitions (.char) */
  46 #define NHYPHS          16384   /* hyphenation dictionary/patterns (.hw) */
  47 #define NHYPHSWORD      16      /* number of hyphenations per word */
  48 #define NHCODES         512     /* number of .hcode characters */
  49 #define WORDLEN         256     /* word length (for hyph.c) */
  50 #define NFEATS          128     /* number of features per font */
  51 #define NSCRPS          128     /* number of scripts per font */
  52
  53 /* converting scales */
  54 #define SC_IN           (dev_res)       /* inch in units */
  55 #define SC_PT           (SC_IN / 72)    /* point in units */
  56 #define SC_EM           (n_s * SC_IN / 72)
  57
  58 /* escape sequences */
  59 #define ESC_Q   "bCDhHjlLNoRSvwxXZ?"    /* \X'ccc' quoted escape sequences */
  60 #define ESC_P   "*fgkmns"               /* \Xc \X(cc \X[ccc] escape sequences */
  61
  62 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
  63 #define MAX(a, b)       ((a) < (b) ? (b) : (a))
  64 #define LEN(a)          (sizeof(a) / sizeof((a)[0]))
  65
  66 /* special characters */
  67 extern int c_ec;        /* escape character (\) */
  68 extern int c_cc;        /* basic control character (.) */
  69 extern int c_c2;        /* no-break control character (') */
  70 extern char c_pc[];     /* page number character (%) */
  71 #define c_ni    4       /* non-interpreted copy-mode escape */
  72 #define c_hc    env_hc()/* hyphenation character */
  73 #define c_mc    env_mc()/* margin character (.mc) */
  74 #define c_tc    env_tc()
  75 #define c_lc    env_lc()
  76 #define c_bp    "\\:"   /* zero-width word break point */
  77 #define c_nb    "\\~"   /* stretchable no-break space */
  78
  79 /* number registers */
  80 #define num_get(id)     (*nreg(id))
  81 void num_set(int id, int val);
  82 void num_inc(int id, int pos);
  83 void num_del(int id);
  84 char *num_str(int id);
  85 char *num_getfmt(int id);
  86 void num_setfmt(int id, char *fmt);
  87 void num_setinc(int id, int val);
  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 /* mapping integers to sets */
 118 struct iset *iset_make(void);
 119 void iset_free(struct iset *iset);
 120 int *iset_get(struct iset *iset, int key);
 121 void iset_put(struct iset *iset, int key, int ent);
 122 int iset_len(struct iset *iset, int key);
 123
 124 /* mapping strings to longs */
 125 struct dict *dict_make(int notfound, int dupkeys, int level2);
 126 void dict_free(struct dict *d);
 127 void dict_put(struct dict *d, char *key, int val);
 128 int dict_get(struct dict *d, char *key);
 129 int dict_idx(struct dict *d, char *key);
 130 char *dict_key(struct dict *d, int idx);
 131 int dict_val(struct dict *d, int idx);
 132 int dict_prefix(struct dict *d, char *key, int *idx);
 133
 134 /* device related variables */
 135 extern int dev_res;
 136 extern int dev_uwid;
 137 extern int dev_hor;
 138 extern int dev_ver;
 139
 140 struct glyph {
 141         char id[GNLEN];         /* device-dependent glyph identifier */
 142         char name[GNLEN];       /* the first character mapped to this glyph */
 143         struct font *font;      /* glyph font */
 144         short wid;              /* character width */
 145         short llx, lly, urx, ury;       /* character bounding box */
 146         short type;             /* character type; ascender/descender */
 147 };
 148
 149 /* output device functions */
 150 int dev_open(char *dir, char *dev);
 151 void dev_close(void);
 152 int dev_mnt(int pos, char *id, char *name);
 153 int dev_pos(char *id);
 154 struct font *dev_font(int pos);
 155 int dev_fontpos(struct font *fn);
 156 struct glyph *dev_glyph(char *c, int fn);
 157
 158 /* font-related functions */
 159 struct font *font_open(char *path);
 160 void font_close(struct font *fn);
 161 struct glyph *font_glyph(struct font *fn, char *id);
 162 struct glyph *font_find(struct font *fn, char *name);
 163 int font_map(struct font *fn, char *name, char *id);
 164 int font_mapped(struct font *fn, char *name);
 165 int font_special(struct font *fn);
 166 int font_wid(struct font *fn, int sz, int w);
 167 int font_gwid(struct font *fn, struct font *cfn, int sz, int w);
 168 int font_swid(struct font *fn, int sz, int ss);
 169 void font_setcs(struct font *fn, int cs, int ps);
 170 int font_getcs(struct font *fn);
 171 void font_setbd(struct font *fn, int bd);
 172 int font_getbd(struct font *fn);
 173 void font_track(struct font *fn, int s1, int n1, int s2, int n2);
 174 void font_setzoom(struct font *fn, int zoom);
 175 int font_zoom(struct font *fn, int sz);
 176 int font_feat(struct font *fn, char *name, int val);
 177 void font_scrp(struct font *fn, char *name);
 178 int font_layout(struct font *fn, struct glyph **src, int nsrc, int sz,
 179                 struct glyph **dst, int *dmap,
 180                 int *x, int *y, int *xadv, int *yadv, int lg, int kn);
 181
 182 /* different layers of neatroff */
 183 int in_next(void);              /* input layer */
 184 int cp_next(void);              /* copy-mode layer */
 185 int tr_next(void);              /* troff layer */
 186
 187 void in_push(char *s, char **args);
 188 void in_so(char *path);         /* .so request */
 189 void in_nx(char *path);         /* .nx request */
 190 void in_ex(void);               /* .ex request */
 191 void in_lf(char *path, int ln); /* .lf request */
 192 void in_queue(char *path);      /* queue the given input file */
 193 char *in_arg(int i);            /* look up argument */
 194 int in_nargs(void);             /* number of arguments */
 195 void in_back(int c);            /* push back input character */
 196 int in_top(void);               /* the first pushed-back character */
 197 char *in_filename(void);        /* current filename */
 198 int in_lnum(void);              /* current line number */
 199
 200 void cp_blk(int skip);          /* skip or read the next line or block */
 201 void cp_reqbeg(void);           /* beginning of a request line */
 202 void cp_copymode(int mode);     /* do not interpret \w and \E */
 203 #define cp_back         in_back /* cp.c is stateless */
 204 int tr_nextreq(void);           /* read the next troff request */
 205
 206 /* variable length string buffer */
 207 struct sbuf {
 208         char *s;                /* allocated buffer */
 209         int sz;                 /* buffer size */
 210         int n;                  /* length of the string stored in s */
 211 };
 212
 213 void sbuf_init(struct sbuf *sbuf);
 214 void sbuf_done(struct sbuf *sbuf);
 215 char *sbuf_out(struct sbuf *sbuf);
 216 char *sbuf_buf(struct sbuf *sbuf);
 217 void sbuf_add(struct sbuf *sbuf, int c);
 218 void sbuf_append(struct sbuf *sbuf, char *s);
 219 void sbuf_printf(struct sbuf *sbuf, char *s, ...);
 220 void sbuf_cut(struct sbuf *sbuf, int n);
 221 int sbuf_len(struct sbuf *sbuf);
 222 int sbuf_empty(struct sbuf *sbuf);
 223
 224 /* word buffer */
 225 struct wb {
 226         struct sbuf sbuf;
 227         int f, s, m;            /* the last output font and size */
 228         int r_f, r_s, r_m;      /* current font and size; use n_f and n_s if -1 */
 229         int part;               /* partial input (\c) */
 230         int cost;               /* the extra cost of line break after this word */
 231         int els_neg, els_pos;   /* extra line spacing */
 232         int h, v;               /* buffer vertical and horizontal positions */
 233         int ct, sb, st;         /* \w registers */
 234         int llx, lly, urx, ury; /* bounding box */
 235         int icleft;             /* pending left italic correction */
 236         /* queued subword */
 237         char sub_c[WORDLEN][GNLEN];     /* the collected subword */
 238         int sub_n;              /* collected subword length */
 239         int sub_collect;        /* enable subword collection */
 240 };
 241
 242 void wb_init(struct wb *wb);
 243 void wb_done(struct wb *wb);
 244 void wb_hmov(struct wb *wb, int n);
 245 void wb_vmov(struct wb *wb, int n);
 246 void wb_els(struct wb *wb, int els);
 247 void wb_etc(struct wb *wb, char *x);
 248 void wb_put(struct wb *wb, char *c);
 249 void wb_putraw(struct wb *wb, char *c);
 250 void wb_putexpand(struct wb *wb, char *c);
 251 int wb_part(struct wb *wb);
 252 void wb_setpart(struct wb *wb);
 253 int wb_cost(struct wb *wb);
 254 void wb_setcost(struct wb *wb, int cost);
 255 void wb_drawl(struct wb *wb, int c, int h, int v);
 256 void wb_drawc(struct wb *wb, int c, int r);
 257 void wb_drawe(struct wb *wb, int c, int h, int v);
 258 void wb_drawa(struct wb *wb, int c, int h1, int v1, int h2, int v2);
 259 void wb_drawxbeg(struct wb *wb, int c);
 260 void wb_drawxdot(struct wb *wb, int h, int v);
 261 void wb_drawxcmd(struct wb *wb, char *cmd);
 262 void wb_drawxend(struct wb *wb);
 263 void wb_italiccorrection(struct wb *wb);
 264 void wb_italiccorrectionleft(struct wb *wb);
 265 void wb_cat(struct wb *wb, struct wb *src);
 266 void wb_catstr(struct wb *wb, char *beg, char *end);
 267 int wb_wid(struct wb *wb);
 268 int wb_hpos(struct wb *wb);
 269 int wb_vpos(struct wb *wb);
 270 int wb_empty(struct wb *wb);
 271 int wb_eos(struct wb *wb);
 272 void wb_wconf(struct wb *wb, int *ct, int *st, int *sb,
 273                 int *llx, int *lly, int *urx, int *ury);
 274 void wb_reset(struct wb *wb);
 275 char *wb_buf(struct wb *wb);
 276 void wb_fnszget(struct wb *wb, int *fn, int *sz, int *m);
 277 void wb_fnszset(struct wb *wb, int fn, int sz, int m);
 278 int wb_hywid(struct wb *wb);
 279 int wb_swid(struct wb *wb);
 280 int c_eossent(char *s);
 281 int c_eostran(char *s);
 282 int c_hydash(char *s);
 283 int c_hystop(char *s);
 284 int c_hymark(char *s);
 285
 286 /* character translation (.tr) */
 287 void cmap_add(char *c1, char *c2);
 288 char *cmap_map(char *c);
 289 /* character definition (.char) */
 290 char *cdef_map(char *c, int fn);
 291 int cdef_expand(struct wb *wb, char *c, int fn);
 292
 293 /* hyphenation flags */
 294 #define HY_LAST         0x02    /* do not hyphenate last lines */
 295 #define HY_FINAL2       0x04    /* do not hyphenate the final two characters */
 296 #define HY_FIRST2       0x08    /* do not hyphenate the first two characters */
 297
 298 void hyphenate(char *hyphs, char *word, int flg);
 299 int hy_cput(char *d, char *s);
 300 void hyph_init(void);
 301 void hyph_done(void);
 302
 303 /* adjustment types */
 304 #define AD_C            0       /* center */
 305 #define AD_L            1       /* adjust left margin (flag) */
 306 #define AD_R            2       /* adjust right margin (flag) */
 307 #define AD_B            3       /* adjust both margin (mask) */
 308 #define AD_P            4       /* paragraph-at-once adjustment (flag) */
 309
 310 /* line formatting */
 311 struct fmt *fmt_alloc(void);
 312 void fmt_free(struct fmt *fmt);
 313 int fmt_wid(struct fmt *fmt);
 314 void fmt_space(struct fmt *fmt);
 315 void fmt_suppressnl(struct fmt *fmt);
 316 int fmt_word(struct fmt *fmt, struct wb *wb);
 317 int fmt_newline(struct fmt *fmt);
 318 int fmt_fillreq(struct fmt *f);
 319 int fmt_fill(struct fmt *fmt, int br);
 320 int fmt_morelines(struct fmt *fmt);
 321 int fmt_morewords(struct fmt *fmt);
 322 char *fmt_nextline(struct fmt *fmt, int *w,
 323                 int *li, int *ll, int *els_neg, int *els_pos);
 324
 325 /* rendering */
 326 int render(void);                               /* the main loop */
 327 int ren_parse(struct wb *wb, char *c);
 328 int ren_char(struct wb *wb, int (*next)(void), void (*back)(int));
 329 int ren_wid(int (*next)(void), void (*back)(int));
 330 void ren_tl(int (*next)(void), void (*back)(int));
 331 void ren_hline(struct wb *wb, int l, char *c);  /* horizontal line */
 332 void ren_hlcmd(struct wb *wb, char *arg);       /* \l */
 333 void ren_vlcmd(struct wb *wb, char *arg);       /* \L */
 334 void ren_bcmd(struct wb *wb, char *arg);        /* \b */
 335 void ren_ocmd(struct wb *wb, char *arg);        /* \o */
 336 void ren_dcmd(struct wb *wb, char *arg);        /* \D */
 337 void ren_zcmd(struct wb *wb, char *arg);        /* \Z */
 338
 339 /* out.c */
 340 void out_line(char *s);                         /* output rendered line */
 341 void out(char *s, ...);                         /* output troff cmd */
 342
 343 /* troff commands */
 344 void tr_ab(char **args);
 345 void tr_bp(char **args);
 346 void tr_br(char **args);
 347 void tr_ce(char **args);
 348 void tr_ch(char **args);
 349 void tr_cl(char **args);
 350 void tr_di(char **args);
 351 void tr_divbeg(char **args);
 352 void tr_divend(char **args);
 353 void tr_divvs(char **args);
 354 void tr_dt(char **args);
 355 void tr_em(char **args);
 356 void tr_ev(char **args);
 357 void tr_fc(char **args);
 358 void tr_fi(char **args);
 359 void tr_fp(char **args);
 360 void tr_fspecial(char **args);
 361 void tr_ft(char **args);
 362 void tr_hcode(char **args);
 363 void tr_hpf(char **args);
 364 void tr_hpfa(char **args);
 365 void tr_hw(char **args);
 366 void tr_in(char **args);
 367 void tr_ll(char **args);
 368 void tr_mk(char **args);
 369 void tr_ne(char **args);
 370 void tr_nf(char **args);
 371 void tr_ns(char **args);
 372 void tr_os(char **args);
 373 void tr_pn(char **args);
 374 void tr_ps(char **args);
 375 void tr_rs(char **args);
 376 void tr_rt(char **args);
 377 void tr_sp(char **args);
 378 void tr_sv(char **args);
 379 void tr_ta(char **args);
 380 void tr_ti(char **args);
 381 void tr_wh(char **args);
 382 void tr_popren(char **args);
 383 void tr_transparent(char **args);
 384
 385 void tr_init(void);
 386 void tr_done(void);
 387
 388 char *tr_args(char **args, int brk, int (*next)(void), void (*back)(int));
 389
 390 /* helpers */
 391 void errmsg(char *msg, ...);
 392 void errdie(char *msg);
 393 void *xmalloc(long len);
 394 void *mextend(void *old, long oldsz, long newsz, int memsz);
 395 /* utf-8 parsing */
 396 int utf8len(int c);
 397 int utf8next(char *s, int (*next)(void));
 398 int utf8read(char **s, char *d);
 399 int utf8one(char *s);
 400 /* reading escapes and characters */
 401 int charnext(char *c, int (*next)(void), void (*back)(int));
 402 int charread(char **s, char *c);
 403 int charnext_delim(char *c, int (*next)(void), void (*back)(int), char *delim);
 404 int charread_delim(char **s, char *c, char *delim);
 405 void charnext_str(char *d, char *c);
 406 char *quotednext(int (*next)(void), void (*back)(int));
 407 char *unquotednext(int cmd, int (*next)(void), void (*back)(int));
 408 int escread(char **s, char **d);
 409 /* string streams; nested next()/back() interface for string buffers */
 410 void sstr_push(char *s);
 411 char *sstr_pop(void);
 412 int sstr_next(void);
 413 void sstr_back(int c);
 414
 415 /* internal commands */
 416 #define TR_DIVBEG       "\07<"  /* diversion begins */
 417 #define TR_DIVEND       "\07>"  /* diversion ends */
 418 #define TR_DIVVS        "\07V"  /* the amount of \n(.v inside diversions */
 419 #define TR_POPREN       "\07P"  /* exit render_rec() */
 420
 421 /* mapping register, macro and environment names to indices */
 422 #define DOTMAP(c2)      (c2)    /* optimized mapping for ".x" names */
 423
 424 int map(char *s);               /* map name s to an index */
 425 char *map_name(int id);         /* return the name mapped to id */
 426 void map_done(void);
 427
 428 /* colors */
 429 #define CLR_R(c)                (((c) >> 16) & 0xff)
 430 #define CLR_G(c)                (((c) >> 8) & 0xff)
 431 #define CLR_B(c)                ((c) & 0xff)
 432 #define CLR_RGB(r, g, b)        (((r) << 16) | ((g) << 8) | (b))
 433
 434 char *clr_str(int c);
 435 int clr_get(char *s);
 436
 437 /* builtin number registers; n_X for .X register */
 438 #define n_a             (*nreg(DOTMAP('a')))
 439 #define n_cp            (*nreg(DOTMAP('C')))
 440 #define n_d             (*nreg(DOTMAP('d')))
 441 #define n_f             (*nreg(DOTMAP('f')))
 442 #define n_h             (*nreg(DOTMAP('h')))
 443 #define n_i             (*nreg(DOTMAP('i')))
 444 #define n_it            (*nreg(map(".it")))     /* .it trap macro */
 445 #define n_itn           (*nreg(map(".itn")))    /* .it lines left */
 446 #define n_j             (*nreg(DOTMAP('j')))
 447 #define n_l             (*nreg(DOTMAP('l')))
 448 #define n_L             (*nreg(DOTMAP('L')))
 449 #define n_n             (*nreg(DOTMAP('n')))
 450 #define n_nI            (*nreg(map(".nI")))     /* i for .nm */
 451 #define n_nm            (*nreg(map(".nm")))     /* .nm enabled */
 452 #define n_nM            (*nreg(map(".nM")))     /* m for .nm */
 453 #define n_nn            (*nreg(map(".nn")))     /* remaining .nn */
 454 #define n_nS            (*nreg(map(".nS")))     /* s for .nm */
 455 #define n_m             (*nreg(DOTMAP('m')))
 456 #define n_mc            (*nreg(map(".mc")))     /* .mc enabled */
 457 #define n_mcn           (*nreg(map(".mcn")))    /* .mc distance */
 458 #define n_o             (*nreg(DOTMAP('o')))
 459 #define n_p             (*nreg(DOTMAP('p')))
 460 #define n_s             (*nreg(DOTMAP('s')))
 461 #define n_u             (*nreg(DOTMAP('u')))
 462 #define n_v             (*nreg(DOTMAP('v')))
 463 #define n_ct            (*nreg(map("ct")))
 464 #define n_dl            (*nreg(map("dl")))
 465 #define n_dn            (*nreg(map("dn")))
 466 #define n_ln            (*nreg(map("ln")))
 467 #define n_nl            (*nreg(map("nl")))
 468 #define n_sb            (*nreg(map("sb")))
 469 #define n_st            (*nreg(map("st")))
 470 #define n_pg            (*nreg(map("%")))       /* % */
 471 #define n_lb            (*nreg(map(".b0")))     /* input line beg */
 472 #define n_ce            (*nreg(map(".ce")))     /* .ce remaining */
 473 #define n_f0            (*nreg(map(".f0")))     /* last .f */
 474 #define n_lg            (*nreg(map(".lg")))     /* .lg mode */
 475 #define n_hy            (*nreg(map(".hy")))     /* .hy mode */
 476 #define n_hycost        (*nreg(map(".hycost"))) /* hyphenation cost */
 477 #define n_hycost2       (*nreg(map(".hycost2")))        /* hyphenation cost #2 */
 478 #define n_hycost3       (*nreg(map(".hycost3")))        /* hyphenation cost #3 */
 479 #define n_hlm           (*nreg(map(".hlm")))    /* .hlm */
 480 #define n_i0            (*nreg(map(".i0")))     /* last .i */
 481 #define n_ti            (*nreg(map(".ti")))     /* pending .ti */
 482 #define n_kn            (*nreg(map(".kn")))     /* .kn mode */
 483 #define n_l0            (*nreg(map(".l0")))     /* last .l */
 484 #define n_L0            (*nreg(map(".L0")))     /* last .L */
 485 #define n_m0            (*nreg(map(".m0")))     /* last .m */
 486 #define n_mk            (*nreg(map(".mk")))     /* .mk internal register */
 487 #define n_na            (*nreg(map(".na")))     /* .na mode */
 488 #define n_ns            (*nreg(map(".ns")))     /* .ns mode */
 489 #define n_o0            (*nreg(map(".o0")))     /* last .o */
 490 #define n_pmll          (*nreg(map(".pmll")))   /* minimum line length (.pmll) */
 491 #define n_pmllcost      (*nreg(map(".pmllcost")))       /* short line cost */
 492 #define n_ss            (*nreg(map(".ss")))     /* word space (.ss) */
 493 #define n_sss           (*nreg(map(".sss")))    /* sentence space (.ss) */
 494 #define n_ssh           (*nreg(map(".ssh")))    /* word space compression (.ssh) */
 495 #define n_s0            (*nreg(map(".s0")))     /* last .s */
 496 #define n_sv            (*nreg(map(".sv")))     /* .sv value */
 497 #define n_lt            (*nreg(map(".lt")))     /* .lt value */
 498 #define n_t0            (*nreg(map(".lt0")))    /* previous .lt value */
 499 #define n_v0            (*nreg(map(".v0")))     /* last .v */
 500 #define n_llx           (*nreg(map("bbllx")))   /* \w bounding box */
 501 #define n_lly           (*nreg(map("bblly")))   /* \w bounding box */
 502 #define n_urx           (*nreg(map("bburx")))   /* \w bounding box */
 503 #define n_ury           (*nreg(map("bbury")))   /* \w bounding box */
 504
 505 /* functions for implementing read-only registers */
 506 int f_nexttrap(void);   /* .t */
 507 int f_divreg(void);     /* .z */
 508 int f_hpos(void);       /* .k */