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