diplodocus.org Git - nmh/blob - sbr/fmt_compile.c

   1
   2 /*
   3  * fmt_compile.c -- "compile" format strings for fmt_scan
   4  *
   5  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   6  * COPYRIGHT file in the root directory of the nmh distribution for
   7  * complete copyright information.
   8  *
   9  * This code compiles the format strings (documented in mh-format(5)) into
  10  * an internal form to be later processed by fmt_scan.c.
  11  *
  12  * What happens here is that the format strings are parsed and an array
  13  * of struct format structures are returned.  Each format structure is
  14  * a single operation interpreted by the the routines in fmt_scan.c.
  15  *
  16  * There is a NOT a one-to-one correspondence between format strings and
  17  * format instructions; some functions have side effects that can result
  18  * in multiple instructions being generated.  The exact list of instructions
  19  * generated by a format string can be seem with the nmh fmtdump utility.
  20  *
  21  * A list of format instructions can be found in fmt_compile.h.
  22  *
  23  * If you wish to add a new function, you will need to do the following
  24  * things:
  25  *
  26  * - Add a new instruction to the list of instructions in fmt_compile.h.
  27  *   Note that test instructions (starting with FT_IF_S_NULL) have special
  28  *   handling, so if you are NOT writing a test function then you need
  29  *   to insert it into the list before that _and_ bump all of the
  30  *   following instruction numbers.
  31  *
  32  * - Add the function name to the functable[] array below, and write any
  33  *   special code that your function may require in terms of parsing
  34  *   (it very well may not need anything).
  35  *
  36  * - Add the code in fmt_scan.c to handle your new function.
  37  *
  38  * - Add code to fmtdump.c to display your new function.
  39  *
  40  * - Document the new function in the mh-format(5) man page.
  41  *
  42  */
  43
  44 #include <h/mh.h>
  45 #include <h/addrsbr.h>
  46 #include <h/tws.h>
  47 #include <h/fmt_scan.h>
  48 #include <h/fmt_compile.h>
  49 #include <h/mts.h>
  50
  51 #ifdef HAVE_SYS_TIME_H
  52 # include <sys/time.h>
  53 #endif
  54 #include <time.h>
  55
  56 /*
  57  * hash table for deciding if a component is "interesting"
  58  */
  59 struct comp *wantcomp[128];
  60
  61 static struct format *formatvec;        /* array to hold formats */
  62 static struct format *next_fp;          /* next free format slot */
  63 static struct format *fp;               /* current format slot   */
  64 static struct comp *cm;                 /* most recent comp ref  */
  65 static struct ftable *ftbl;             /* most recent func ref  */
  66 static int ncomp;
  67 static int infunction;                  /* function nesting cnt  */
  68
  69 extern struct mailname fmt_mnull;
  70
  71 /* ftable->type (argument type) */
  72 #define TF_COMP    0        /* component expected                 */
  73 #define TF_NUM     1        /* number expected                    */
  74 #define TF_STR     2        /* string expected                    */
  75 #define TF_EXPR    3        /* component or func. expected        */
  76 #define TF_NONE    4        /* no argument                        */
  77 #define TF_MYBOX   5        /* special - get current user's mbox  */
  78 #define TF_NOW     6        /* special - get current unix time    */
  79 #define TF_EXPR_SV 7        /* like expr but save current str reg */
  80 #define TF_NOP     8        /* like expr but no result            */
  81 #define TF_MYNAME  9        /* special - get current name of user */
  82 #define TF_MYHOST  10       /* special - get "local" hostname     */
  83 #define TF_LMBOX   11       /* special - get full local mailbox   */
  84
  85 /* ftable->flags */
  86 /* NB that TFL_PUTS is also used to decide whether the test
  87  * in a "%<(function)..." should be a string or numeric one.
  88  */
  89 #define TFL_PUTS   1        /* implicit putstr if top level */
  90 #define TFL_PUTN   2        /* implicit putnum if top level */
  91
  92 /*
  93  * The functable array maps between the text names of format functions and
  94  * the format instructions interpreted by the engine in fmt_scan.c.
  95  *
  96  * The elements of this structure are as follows:
  97  *
  98  * name -   The name of the function as seen in the format string.  This is
  99  *          what maps a particular function name into a format instruction.
 100  * type -   The type of argument this function expects.  Those types are
 101  *          listed above (with the TF_ prefix).  This affects what gets
 102  *          placed in the format instruction (the f_un union).
 103  * f_type - The instruction corresponding to this function (from the list
 104  *          in fmt_compile.h).
 105  * extra  - Used by some functions to provide extra data to the compiler.
 106  *          Uses include:
 107  *              - Providing an alternate instruction to combine a load
 108  *                and test operation (see do_if()).
 109  *              - Passed in f_value in the format instruction to provide
 110  *                extra information for the engine (see FT_LV_DAT handling
 111  *                in fmt_scan.c).
 112  *              - Provide a hint as to preprocessing that is required for
 113  *                this instruction (see do_name()).
 114  * flags  - See the definitions for TFL_PUTS & TFL_PUTN above.
 115  */
 116
 117 struct ftable {
 118     char *name;         /* function name                  */
 119     char type;          /* argument type                  */
 120     char f_type;        /* fmt type                       */
 121     char extra;         /* arg. type dependent extra info */
 122     char flags;
 123 };
 124
 125 static struct ftable functable[] = {
 126      { "nonzero",    TF_EXPR,   FT_V_NE,        FT_IF_V_NE,     0 },
 127      { "zero",       TF_EXPR,   FT_V_EQ,        FT_IF_V_EQ,     0 },
 128      { "eq",         TF_NUM,    FT_V_EQ,        FT_IF_V_EQ,     0 },
 129      { "ne",         TF_NUM,    FT_V_NE,        FT_IF_V_NE,     0 },
 130      { "gt",         TF_NUM,    FT_V_GT,        FT_IF_V_GT,     0 },
 131      { "null",       TF_EXPR,   FT_S_NULL,      FT_IF_S_NULL,   0 },
 132      { "nonnull",    TF_EXPR,   FT_S_NONNULL,   FT_IF_S,        0 },
 133      { "match",      TF_STR,    FT_V_MATCH,     FT_IF_MATCH,    0 },
 134      { "amatch",     TF_STR,    FT_V_AMATCH,    FT_IF_AMATCH,   0 },
 135
 136      { "putstr",     TF_EXPR,   FT_STR,         0,              0 },
 137      { "putstrf",    TF_EXPR,   FT_STRF,        0,              0 },
 138      { "putnum",     TF_EXPR,   FT_NUM,         0,              0 },
 139      { "putnumf",    TF_EXPR,   FT_NUMF,        0,              0 },
 140      { "putaddr",    TF_STR,    FT_PUTADDR,     0,              0 },
 141      { "putlit",     TF_STR,    FT_STRLIT,      0,              0 },
 142      { "zputlit",    TF_STR,    FT_STRLITZ,     0,              0 },
 143      { "void",       TF_NOP,    0,              0,              0 },
 144
 145      { "comp",       TF_COMP,   FT_LS_COMP,     0,              TFL_PUTS },
 146      { "lit",        TF_STR,    FT_LS_LIT,      0,              TFL_PUTS },
 147      { "getenv",     TF_STR,    FT_LS_GETENV,   0,              TFL_PUTS },
 148      { "profile",    TF_STR,    FT_LS_CFIND,    0,              TFL_PUTS },
 149      { "decodecomp", TF_COMP,   FT_LS_DECODECOMP, 0,            TFL_PUTS },
 150      { "decode",     TF_EXPR,   FT_LS_DECODE,   0,              TFL_PUTS },
 151      { "trim",       TF_EXPR,   FT_LS_TRIM,     0,              0 },
 152      { "compval",    TF_COMP,   FT_LV_COMP,     0,              TFL_PUTN },
 153      { "compflag",   TF_COMP,   FT_LV_COMPFLAG, 0,              TFL_PUTN },
 154      { "num",        TF_NUM,    FT_LV_LIT,      0,              TFL_PUTN },
 155      { "msg",        TF_NONE,   FT_LV_DAT,      0,              TFL_PUTN },
 156      { "cur",        TF_NONE,   FT_LV_DAT,      1,              TFL_PUTN },
 157      { "size",       TF_NONE,   FT_LV_DAT,      2,              TFL_PUTN },
 158      { "width",      TF_NONE,   FT_LV_DAT,      3,              TFL_PUTN },
 159      { "unseen",     TF_NONE,   FT_LV_DAT,      4,              TFL_PUTN },
 160      { "dat",        TF_NUM,    FT_LV_DAT,      0,              TFL_PUTN },
 161      { "strlen",     TF_NONE,   FT_LV_STRLEN,   0,              TFL_PUTN },
 162      { "me",         TF_MYBOX,  FT_LS_LIT,      0,              TFL_PUTS },
 163      { "myname",     TF_MYNAME, FT_LS_LIT,      0,              TFL_PUTS },
 164      { "myhost",     TF_MYHOST, FT_LS_LIT,      0,              TFL_PUTS },
 165      { "localmbox",  TF_LMBOX,  FT_LS_LIT,      0,              TFL_PUTS },
 166      { "plus",       TF_NUM,    FT_LV_PLUS_L,   0,              TFL_PUTN },
 167      { "minus",      TF_NUM,    FT_LV_MINUS_L,  0,              TFL_PUTN },
 168      { "divide",     TF_NUM,    FT_LV_DIVIDE_L, 0,              TFL_PUTN },
 169      { "modulo",     TF_NUM,    FT_LV_MODULO_L, 0,              TFL_PUTN },
 170      { "charleft",   TF_NONE,   FT_LV_CHAR_LEFT, 0,             TFL_PUTN },
 171      { "timenow",    TF_NOW,    FT_LV_LIT,      0,              TFL_PUTN },
 172
 173      { "month",      TF_COMP,   FT_LS_MONTH,    FT_PARSEDATE,   TFL_PUTS },
 174      { "lmonth",     TF_COMP,   FT_LS_LMONTH,   FT_PARSEDATE,   TFL_PUTS },
 175      { "tzone",      TF_COMP,   FT_LS_ZONE,     FT_PARSEDATE,   TFL_PUTS },
 176      { "day",        TF_COMP,   FT_LS_DAY,      FT_PARSEDATE,   TFL_PUTS },
 177      { "weekday",    TF_COMP,   FT_LS_WEEKDAY,  FT_PARSEDATE,   TFL_PUTS },
 178      { "tws",        TF_COMP,   FT_LS_822DATE,  FT_PARSEDATE,   TFL_PUTS },
 179      { "sec",        TF_COMP,   FT_LV_SEC,      FT_PARSEDATE,   TFL_PUTN },
 180      { "min",        TF_COMP,   FT_LV_MIN,      FT_PARSEDATE,   TFL_PUTN },
 181      { "hour",       TF_COMP,   FT_LV_HOUR,     FT_PARSEDATE,   TFL_PUTN },
 182      { "mday",       TF_COMP,   FT_LV_MDAY,     FT_PARSEDATE,   TFL_PUTN },
 183      { "mon",        TF_COMP,   FT_LV_MON,      FT_PARSEDATE,   TFL_PUTN },
 184      { "year",       TF_COMP,   FT_LV_YEAR,     FT_PARSEDATE,   TFL_PUTN },
 185      { "yday",       TF_COMP,   FT_LV_YDAY,     FT_PARSEDATE,   TFL_PUTN },
 186      { "wday",       TF_COMP,   FT_LV_WDAY,     FT_PARSEDATE,   TFL_PUTN },
 187      { "zone",       TF_COMP,   FT_LV_ZONE,     FT_PARSEDATE,   TFL_PUTN },
 188      { "clock",      TF_COMP,   FT_LV_CLOCK,    FT_PARSEDATE,   TFL_PUTN },
 189      { "rclock",     TF_COMP,   FT_LV_RCLOCK,   FT_PARSEDATE,   TFL_PUTN },
 190      { "sday",       TF_COMP,   FT_LV_DAYF,     FT_PARSEDATE,   TFL_PUTN },
 191      { "szone",      TF_COMP,   FT_LV_ZONEF,    FT_PARSEDATE,   TFL_PUTN },
 192      { "dst",        TF_COMP,   FT_LV_DST,      FT_PARSEDATE,   TFL_PUTN },
 193      { "pretty",     TF_COMP,   FT_LS_PRETTY,   FT_PARSEDATE,   TFL_PUTS },
 194      { "nodate",     TF_COMP,   FT_LV_COMPFLAG, FT_PARSEDATE,   TFL_PUTN },
 195      { "date2local", TF_COMP,   FT_LOCALDATE,   FT_PARSEDATE,   0 },
 196      { "date2gmt",   TF_COMP,   FT_GMTDATE,     FT_PARSEDATE,   0 },
 197
 198      { "pers",       TF_COMP,   FT_LS_PERS,     FT_PARSEADDR,   TFL_PUTS },
 199      { "mbox",       TF_COMP,   FT_LS_MBOX,     FT_PARSEADDR,   TFL_PUTS },
 200      { "host",       TF_COMP,   FT_LS_HOST,     FT_PARSEADDR,   TFL_PUTS },
 201      { "path",       TF_COMP,   FT_LS_PATH,     FT_PARSEADDR,   TFL_PUTS },
 202      { "gname",      TF_COMP,   FT_LS_GNAME,    FT_PARSEADDR,   TFL_PUTS },
 203      { "note",       TF_COMP,   FT_LS_NOTE,     FT_PARSEADDR,   TFL_PUTS },
 204      { "addr",       TF_COMP,   FT_LS_ADDR,     FT_PARSEADDR,   TFL_PUTS },
 205      { "proper",     TF_COMP,   FT_LS_822ADDR,  FT_PARSEADDR,   TFL_PUTS },
 206      { "type",       TF_COMP,   FT_LV_HOSTTYPE, FT_PARSEADDR,   TFL_PUTN },
 207      { "ingrp",      TF_COMP,   FT_LV_INGRPF,   FT_PARSEADDR,   TFL_PUTN },
 208      { "nohost",     TF_COMP,   FT_LV_NOHOSTF,  FT_PARSEADDR,   TFL_PUTN },
 209      { "formataddr", TF_EXPR_SV,FT_FORMATADDR,  FT_FORMATADDR,  0 },
 210      { "concataddr", TF_EXPR_SV,FT_CONCATADDR,  FT_FORMATADDR,  0 },
 211      { "friendly",   TF_COMP,   FT_LS_FRIENDLY, FT_PARSEADDR,   TFL_PUTS },
 212
 213      { "mymbox",     TF_COMP,   FT_LV_COMPFLAG, FT_MYMBOX,      TFL_PUTN },
 214      { "addtoseq",   TF_STR,    FT_ADDTOSEQ,    0,              0 },
 215
 216      { "unquote",   TF_EXPR,    FT_LS_UNQUOTE,  0,              TFL_PUTS},
 217
 218      { NULL,         0,         0,              0,              0 }
 219 };
 220
 221 /* Add new component to the hash table */
 222 #define NEWCOMP(cm,name) do { \
 223         cm = ((struct comp *) calloc(1, sizeof (struct comp)));\
 224         cm->c_name = name;\
 225         ncomp++;\
 226         i = CHASH(name);\
 227         cm->c_next = wantcomp[i];\
 228         wantcomp[i] = cm; \
 229         } while (0)
 230
 231 #define NEWFMT (next_fp++)
 232 #define NEW(type,fill,wid) do {\
 233         fp=NEWFMT; fp->f_type=(type); fp->f_fill=(fill); fp->f_width=(wid); \
 234         } while (0)
 235
 236 /* Add (possibly new) component to the hash table */
 237 #define ADDC(name) do { \
 238         FINDCOMP(cm, name);\
 239         if (!cm) {\
 240             NEWCOMP(cm,name);\
 241         }\
 242         fp->f_comp = cm; \
 243         } while (0)
 244
 245 #define LV(type, value)         do { NEW(type,0,0); fp->f_value = (value); } while (0)
 246 #define LS(type, str)           do { NEW(type,0,0); fp->f_text = (str); } while (0)
 247
 248 #define PUTCOMP(comp)           do { NEW(FT_COMP,0,0); ADDC(comp); } while (0)
 249 #define PUTLIT(str)             do { NEW(FT_LIT,0,0); fp->f_text = (str); } while (0)
 250 #define PUTC(c)                 do { NEW(FT_CHAR,0,0); fp->f_char = (c); } while (0)
 251
 252 char *format_string;
 253 static unsigned char *usr_fstring;      /* for CERROR */
 254
 255 #define CERROR(str) compile_error (str, cp)
 256
 257 /*
 258  * static prototypes
 259  */
 260 static struct ftable *lookup(char *);
 261 static void compile_error(char *, char *);
 262 static char *compile (char *);
 263 static char *do_spec(char *);
 264 static char *do_name(char *, int);
 265 static char *do_func(char *);
 266 static char *do_expr (char *, int);
 267 static char *do_loop(char *);
 268 static char *do_if(char *);
 269
 270
 271 /*
 272  * Lookup a function name in the functable
 273  */
 274 static struct ftable *
 275 lookup(char *name)
 276 {
 277     register struct ftable *t = functable;
 278     register char *nm;
 279     register char c = *name;
 280
 281     while ((nm = t->name)) {
 282         if (*nm == c && strcmp (nm, name) == 0)
 283             return (ftbl = t);
 284
 285         t++;
 286     }
 287     return (struct ftable *) 0;
 288 }
 289
 290
 291 static void
 292 compile_error(char *str, char *cp)
 293 {
 294     int i, errpos, errctx;
 295
 296     errpos = cp - format_string;
 297     errctx = errpos > 20 ? 20 : errpos;
 298     usr_fstring[errpos] = '\0';
 299
 300     for (i = errpos-errctx; i < errpos; i++) {
 301 #ifdef LOCALE
 302         if (iscntrl(usr_fstring[i]))
 303 #else
 304         if (usr_fstring[i] < 32)
 305 #endif
 306             usr_fstring[i] = '_';
 307     }
 308
 309     advise(NULL, "\"%s\": format compile error - %s",
 310            &usr_fstring[errpos-errctx], str);
 311     adios (NULL, "%*s", errctx+1, "^");
 312 }
 313
 314 /*
 315  * Compile format string "fstring" into format list "fmt".
 316  * Return the number of header components found in the format
 317  * string.
 318  */
 319
 320 int
 321 fmt_compile(char *fstring, struct format **fmt)
 322 {
 323     register char *cp;
 324     size_t i;
 325
 326     if (format_string)
 327         free (format_string);
 328     format_string = getcpy (fstring);
 329     usr_fstring = fstring;
 330
 331     /* init the component hash table. */
 332     for (i = 0; i < sizeof(wantcomp)/sizeof(wantcomp[0]); i++)
 333         wantcomp[i] = 0;
 334
 335     memset((char *) &fmt_mnull, 0, sizeof(fmt_mnull));
 336
 337     /* it takes at least 4 char to generate one format so we
 338      * allocate a worst-case format array using 1/4 the length
 339      * of the format string.  We actually need twice this much
 340      * to handle both pre-processing (e.g., address parsing) and
 341      * normal processing.
 342      */
 343     i = strlen(fstring)/2 + 1;
 344                 if (i==1) i++;
 345     next_fp = formatvec = (struct format *)calloc ((size_t) i,
 346                                                    sizeof(struct format));
 347     if (next_fp == NULL)
 348         adios (NULL, "unable to allocate format storage");
 349
 350     ncomp = 0;
 351     infunction = 0;
 352
 353     cp = compile(format_string);
 354     if (*cp) {
 355         CERROR("extra '%>', '%|' or '%?'");
 356     }
 357     LV(FT_DONE, 0);             /* really done */
 358     *fmt = formatvec;
 359
 360     return (ncomp);
 361 }
 362
 363 static char *
 364 compile (char *sp)
 365 {
 366     register char *cp = sp;
 367     register int  c;
 368
 369     for (;;) {
 370         sp = cp;
 371         while ((c = *cp) && c != '%')
 372             cp++;
 373         *cp = 0;
 374         switch (cp-sp) {
 375         case 0:
 376             break;
 377         case 1:
 378             PUTC(*sp);
 379             break;
 380         default:
 381             PUTLIT(sp);
 382             break;
 383         }
 384         if (c == 0)
 385             return (cp);
 386
 387         switch (c = *++cp) {
 388         case '%':
 389             PUTC (*cp);
 390             cp++;
 391             break;
 392
 393         case '|':
 394         case '>':
 395         case '?':
 396         case ']':
 397             return (cp);
 398
 399         case '<':
 400             cp = do_if(++cp);
 401             break;
 402
 403         case '[':       /* ] */
 404             cp = do_loop(++cp);
 405             break;
 406
 407         case ';':       /* comment line */
 408             cp++;
 409             while ((c = *cp++) && c != '\n')
 410                 continue;
 411             break;
 412
 413         default:
 414             cp = do_spec(cp);
 415             break;
 416         }
 417     }
 418 }
 419
 420
 421 /*
 422  * Process functions & components (handle field width here as well
 423  */
 424 static char *
 425 do_spec(char *sp)
 426 {
 427     register char *cp = sp;
 428     register int c;
 429 #ifndef lint
 430     register int ljust = 0;
 431 #endif  /* not lint */
 432     register int wid = 0;
 433     register char fill = ' ';
 434
 435     c = *cp++;
 436     if (c == '-') {
 437         ljust++;
 438         c = *cp++;
 439     }
 440     if (c == '0') {
 441         fill = c;
 442         c = *cp++;
 443     }
 444     while (isdigit(c)) {
 445         wid = wid*10 + (c - '0');
 446         c = *cp++;
 447     }
 448     if (c == '{') {
 449         cp = do_name(cp, 0);
 450         if (! infunction)
 451             fp->f_type = wid? FT_COMPF : FT_COMP;
 452     }
 453     else if (c == '(') {
 454         cp = do_func(cp);
 455         if (! infunction) {
 456             if (ftbl->flags & TFL_PUTS) {
 457                 LV( wid? FT_STRF : FT_STR, ftbl->extra);
 458             }
 459             else if (ftbl->flags & TFL_PUTN) {
 460                 LV( wid? FT_NUMF : FT_NUM, ftbl->extra);
 461             }
 462         }
 463     }
 464     else {
 465         CERROR("component or function name expected");
 466     }
 467     if (ljust)
 468         wid = -wid;
 469     fp->f_width = wid;
 470     fp->f_fill = fill;
 471
 472     return (cp);
 473 }
 474
 475 /*
 476  * Process a component name.  Normally this involves generating an FT_COMP
 477  * instruction for the specified component.  If preprocess is set, then we
 478  * do some extra processing.
 479  */
 480 static char *
 481 do_name(char *sp, int preprocess)
 482 {
 483     register char *cp = sp;
 484     register int c;
 485     register int i;
 486     static int primed = 0;
 487
 488     while (isalnum(c = *cp++) || c == '-' || c == '_')
 489         ;
 490     if (c != '}') {
 491         CERROR("'}' expected");
 492     }
 493     cp[-1] = '\0';
 494     PUTCOMP(sp);
 495     switch (preprocess) {
 496
 497     case FT_PARSEDATE:
 498         if (cm->c_type & CT_ADDR) {
 499             CERROR("component used as both date and address");
 500         }
 501         cm->c_tws = (struct tws *)
 502             calloc((size_t) 1, sizeof(*cm->c_tws));
 503         fp->f_type = preprocess;
 504         PUTCOMP(sp);
 505         cm->c_type |= CT_DATE;
 506         break;
 507
 508     case FT_MYMBOX:
 509         if (!primed) {
 510             ismymbox ((struct mailname *) 0);
 511             primed++;
 512         }
 513         /* fall through */
 514     case FT_PARSEADDR:
 515         if (cm->c_type & CT_DATE) {
 516             CERROR("component used as both date and address");
 517         }
 518         cm->c_mn = &fmt_mnull;
 519         fp->f_type = preprocess;
 520         PUTCOMP(sp);
 521         cm->c_type |= CT_ADDR;
 522         break;
 523
 524     case FT_FORMATADDR:
 525         if (cm->c_type & CT_DATE) {
 526             CERROR("component used as both date and address");
 527         }
 528         cm->c_type |= CT_ADDR;
 529         break;
 530     }
 531     return (cp);
 532 }
 533
 534 /*
 535  * Generate one or more instructions corresponding to the named function.
 536  * The different type of function arguments are handled here.
 537  */
 538 static char *
 539 do_func(char *sp)
 540 {
 541     register char *cp = sp;
 542     register int c;
 543     register struct ftable *t;
 544     register int n;
 545     int mflag;          /* minus sign in NUM */
 546
 547     infunction++;
 548
 549     while (isalnum(c = *cp++))
 550         ;
 551     if (c != '(' && c != '{' && c != ' ' && c != ')') {
 552         CERROR("'(', '{', ' ' or ')' expected");
 553     }
 554     cp[-1] = '\0';
 555     if ((t = lookup (sp)) == 0) {
 556         CERROR("unknown function");
 557     }
 558     if (isspace(c))
 559         c = *cp++;
 560
 561     switch (t->type) {
 562
 563     case TF_COMP:
 564         if (c != '{') {
 565             CERROR("component name expected");
 566         }
 567         cp = do_name(cp, t->extra);
 568         fp->f_type = t->f_type;
 569         c = *cp++;
 570         break;
 571
 572     case TF_NUM:
 573         if ((mflag = (c == '-')))
 574             c = *cp++;
 575         n = 0;
 576         while (isdigit(c)) {
 577             n = n*10 + (c - '0');
 578             c = *cp++;
 579         }
 580         if (mflag)
 581             n = (-n);
 582         LV(t->f_type,n);
 583         break;
 584
 585     case TF_STR:
 586         sp = cp - 1;
 587         while (c && c != ')')
 588             c = *cp++;
 589         cp[-1] = '\0';
 590         LS(t->f_type,sp);
 591         break;
 592
 593     case TF_NONE:
 594         LV(t->f_type,t->extra);
 595         break;
 596
 597     case TF_MYBOX:
 598         LS(t->f_type, getusername());
 599         break;
 600
 601     case TF_MYNAME:
 602         LS(t->f_type, getfullname());
 603         break;
 604
 605     case TF_MYHOST:
 606         LS(t->f_type, LocalName(0));
 607         break;
 608
 609     case TF_LMBOX:
 610         LS(t->f_type, getlocalmbox());
 611         break;
 612
 613     case TF_NOW:
 614         LV(t->f_type, time((time_t *) 0));
 615         break;
 616
 617     case TF_EXPR_SV:
 618         LV(FT_SAVESTR, 0);
 619         /* fall through */
 620     case TF_EXPR:
 621         *--cp = c;
 622         cp = do_expr(cp, t->extra);
 623         LV(t->f_type, 0);
 624         c = *cp++;
 625         ftbl = t;
 626         break;
 627
 628     case TF_NOP:
 629         *--cp = c;
 630         cp = do_expr(cp, t->extra);
 631         c = *cp++;
 632         ftbl = t;
 633         break;
 634     }
 635     if (c != ')') {
 636         CERROR("')' expected");
 637     }
 638     --infunction;
 639     return (cp);
 640 }
 641
 642 /*
 643  * Handle an expression as an argument.  Basically we call one of do_name(),
 644  * do_func(), or do_if()
 645  */
 646 static char *
 647 do_expr (char *sp, int preprocess)
 648 {
 649     register char *cp = sp;
 650     register int  c;
 651
 652     if ((c = *cp++) == '{') {
 653         cp = do_name (cp, preprocess);
 654         fp->f_type = FT_LS_COMP;
 655     } else if (c == '(') {
 656         cp = do_func (cp);
 657     } else if (c == ')') {
 658         return (--cp);
 659     } else if (c == '%' && *cp == '<') {
 660         cp = do_if (cp+1);
 661     } else {
 662         CERROR ("'(', '{', '%<' or ')' expected");
 663     }
 664     return (cp);
 665 }
 666
 667 /*
 668  * I am guessing this was for some kind of loop statement, which would have
 669  * looked like %[ .... %].  It looks like the way this would have worked
 670  * is that the format engine would have seen that FT_DONE had a 1 in the
 671  * f_un.f_un_value and then decided whether or not to continue the loop.
 672  * There is no support for this in the format engine, so right now if
 673  * you try using it you will reach the FT_DONE and simply stop.  I'm leaving
 674  * this here in case someone wants to continue the work.
 675  */
 676 static char *
 677 do_loop(char *sp)
 678 {
 679     register char *cp = sp;
 680     struct format *floop;
 681
 682     floop = next_fp;
 683     cp = compile (cp);
 684     if (*cp++ != ']')
 685         CERROR ("']' expected");
 686
 687     LV(FT_DONE, 1);             /* not yet done */
 688     LV(FT_GOTO, 0);
 689     fp->f_skip = floop - fp;    /* skip backwards */
 690
 691     return cp;
 692 }
 693
 694 /*
 695  * Handle an if-elsif-endif statement.  Note here that the branching
 696  * is handled by the f_skip member of the struct format (which is really
 697  * just f_width overloaded).  This number controls how far to move forward
 698  * (or back) in the format instruction array.
 699  */
 700 static char *
 701 do_if(char *sp)
 702 {
 703     register char *cp = sp;
 704     register struct format *fexpr,
 705                            *fif = (struct format *)NULL;
 706     register int c = '<';
 707
 708     for (;;) {
 709         if (c == '<') {                 /* doing an IF */
 710             if ((c = *cp++) == '{') /*}*/{
 711                 cp = do_name(cp, 0);
 712                 fp->f_type = FT_LS_COMP;
 713                 LV (FT_IF_S, 0);
 714             }
 715             else if (c == '(') {
 716                 cp = do_func(cp);
 717                 /* see if we can merge the load and the "if" */
 718                 if (ftbl->f_type >= IF_FUNCS)
 719                     fp->f_type = ftbl->extra;
 720                 else {
 721                     /* Put out a string test or a value test depending
 722                      * on what this function's return type is.
 723                      */
 724                     if (ftbl->flags & TFL_PUTS) {
 725                         LV (FT_IF_S, 0);
 726                     } else {
 727                         LV (FT_IF_V_NE, 0);
 728                     }
 729                 }
 730             }
 731             else {
 732                 CERROR("'(' or '{' expected");  /*}*/
 733             }
 734         }
 735
 736         fexpr = fp;                     /* loc of [ELS]IF */
 737         cp = compile (cp);              /* compile IF TRUE stmts */
 738         if (fif)
 739             fif->f_skip = next_fp - fif;
 740
 741         if ((c = *cp++) == '|') {       /* the last ELSE */
 742             LV(FT_GOTO, 0);
 743             fif = fp;                   /* loc of GOTO */
 744             fexpr->f_skip = next_fp - fexpr;
 745
 746             fexpr = (struct format *)NULL;/* no extra ENDIF */
 747
 748             cp = compile (cp);          /* compile ELSE stmts */
 749             fif->f_skip = next_fp - fif;
 750             c = *cp++;
 751         }
 752         else if (c == '?') {            /* another ELSIF */
 753             LV(FT_GOTO, 0);
 754             fif = fp;                   /* loc of GOTO */
 755             fexpr->f_skip = next_fp - fexpr;
 756
 757             c = '<';                    /* impersonate an IF */
 758             continue;
 759         }
 760         break;
 761     }
 762
 763     if (c != '>') {
 764         CERROR("'>' expected.");
 765     }
 766
 767     if (fexpr)                          /* IF ... [ELSIF ...] ENDIF */
 768         fexpr->f_skip = next_fp - fexpr;
 769
 770     return (cp);
 771 }