src/compile.c

   1 /*
   2  * Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.
   3  *
   4  * This file is part of Jam - see jam.c for Copyright information.
   5  */
   6 /*
   7  * compile.c - compile parsed jam statements
   8  *
   9  * External routines:
  10  *
  11  *  compile_append() - append list results of two statements
  12  *  compile_break() - compile 'break/continue/return' rule
  13  *  compile_eval() - evaluate if to determine which leg to compile
  14  *  compile_foreach() - compile the "for x in y" statement
  15  *  compile_if() - compile 'if' rule
  16  *  compile_include() - support for 'include' - call include() on file
  17  *  compile_list() - expand and return a list
  18  *  compile_local() - declare (and set) local variables
  19  *  compile_null() - do nothing -- a stub for parsing
  20  *  compile_on() - run rule under influence of on-target variables
  21  *  compile_rule() - compile a single user defined rule
  22  *  compile_rules() - compile a chain of rules
  23  *  compile_set() - compile the "set variable" statement
  24  *  compile_setcomp() - support for `rule` - save parse tree
  25  *  compile_setexec() - support for `actions` - save execution string
  26  *  compile_settings() - compile the "on =" (set variable on exec) statement
  27  *  compile_switch() - compile 'switch' rule
  28  *
  29  * Internal routines:
  30  *
  31  *  debug_compile() - printf with indent to show rule expansion.
  32  *  evaluate_rule() - execute a rule invocation
  33  *
  34  * 02/03/94 (seiwald) - Changed trace output to read "setting" instead of
  35  *      the awkward sounding "settings".
  36  * 04/12/94 (seiwald) - Combined build_depends() with build_includes().
  37  * 04/12/94 (seiwald) - actionlist() now just appends a single action.
  38  * 04/13/94 (seiwald) - added shorthand L0 for null list pointer
  39  * 05/13/94 (seiwald) - include files are now bound as targets, and thus
  40  *      can make use of $(SEARCH)
  41  * 06/01/94 (seiwald) - new 'actions existing' does existing sources
  42  * 08/23/94 (seiwald) - Support for '+=' (append to variable)
  43  * 12/20/94 (seiwald) - NOTIME renamed NOTFILE.
  44  * 01/22/95 (seiwald) - Exit rule.
  45  * 02/02/95 (seiwald) - Always rule; LEAVES rule.
  46  * 02/14/95 (seiwald) - NoUpdate rule.
  47  * 01/20/00 (seiwald) - Upgraded from K&R to ANSI C
  48  * 09/07/00 (seiwald) - stop crashing when a rule redefines itself
  49  * 09/11/00 (seiwald) - new evaluate_rule() for headers().
  50  * 09/11/00 (seiwald) - rules now return values, accessed via [ rule arg ... ]
  51  * 09/12/00 (seiwald) - don't complain about rules invoked without targets
  52  * 01/13/01 (seiwald) - fix case where rule is defined within another
  53  * 01/10/01 (seiwald) - built-ins split out to builtin.c.
  54  * 01/11/01 (seiwald) - optimize compile_rules() for tail recursion
  55  * 01/21/01 (seiwald) - replace evaluate_if() with compile_eval()
  56  * 01/24/01 (seiwald) - 'while' statement
  57  * 03/23/01 (seiwald) - "[ on target rule ]" support
  58  * 02/28/02 (seiwald) - merge EXEC_xxx flags in with RULE_xxx
  59  * 03/02/02 (seiwald) - rules can be invoked via variable names
  60  * 03/12/02 (seiwald) - &&,&,||,|,in now short-circuit again
  61  * 03/25/02 (seiwald) - if ( "" a b ) one again returns true
  62  * 06/21/02 (seiwald) - support for named parameters
  63  * 10/22/02 (seiwald) - list_new() now does its own newstr()/copystr()
  64  * 10/22/02 (seiwald) - working return/break/continue statements
  65  * 11/04/02 (seiwald) - const-ing for string literals
  66  * 11/18/02 (seiwald) - remove bogus search() in 'on' statement.
  67  * 12/17/02 (seiwald) - new copysettings() to protect target-specific vars
  68  */
  69 #include "jam.h"
  70
  71 #include "lists.h"
  72 #include "parse.h"
  73 #include "compile.h"
  74 #include "variable.h"
  75 #include "expand.h"
  76 #include "rules.h"
  77 #include "newstr.h"
  78 #include "search.h"
  79 #include "matchglob.h"
  80
  81
  82 static const char *set_names[] = { "=", "+=", "-=", "?=" };
  83 static void debug_compile (int which, const char *s);
  84
  85
  86 /*
  87  * compile_append() - append list results of two statements
  88  *
  89  *  parse->left   more compile_append() by left-recursion
  90  *  parse->right  single rule
  91  */
  92 LIST *compile_append (PARSE *parse, LOL *args, int *jmp) {
  93   /* Append right to left. */
  94   return list_append(
  95     (*parse->left->func)(parse->left, args, jmp),
  96     (*parse->right->func)(parse->right, args, jmp)
  97   );
  98 }
  99
 100
 101 /*
 102  * compile_break() - compile 'break/continue/return' rule
 103  *
 104  *  parse->left  results
 105  *  parse->num   JMP_BREAK/CONTINUE/RETURN
 106  */
 107 LIST *compile_break (PARSE *parse, LOL *args, int *jmp) {
 108   LIST *lv = (*parse->left->func)(parse->left, args, jmp);
 109   *jmp = parse->num;
 110   return lv;
 111 }
 112
 113
 114 /*
 115  * compile_eval() - evaluate if to determine which leg to compile
 116  *
 117  * Returns:
 118  *  list  if expression true - compile 'then' clause
 119  *  L0    if expression false - compile 'else' clause
 120  */
 121 static JAMFA_PURE int lcmp (LIST *t, LIST *s) {
 122   int status = 0;
 123   //
 124   while (!status && (t || s)) {
 125     const char *st = t?t->string:"";
 126     const char *ss = s?s->string:"";
 127     //
 128     status = strcmp(st, ss);
 129     t = t?list_next(t):t;
 130     s = s?list_next(s):s;
 131   }
 132   return status;
 133 }
 134
 135
 136 LIST *compile_eval (PARSE *parse, LOL *args, int *jmp) {
 137   LIST *ll, *lr, *s, *t;
 138   int status = 0;
 139   //
 140   /* short circuit lr eval for &&, ||, and 'in' */
 141   ll = (*parse->left->func)(parse->left, args, jmp);
 142   lr = 0;
 143   switch (parse->num) {
 144     case EXPR_AND:
 145     case EXPR_IN:
 146       if (ll) goto eval;
 147       break;
 148     case EXPR_OR:
 149       if (!ll) goto eval;
 150       break;
 151     default:
 152 eval: lr = (*parse->right->func)(parse->right, args, jmp);
 153       break;
 154   }
 155   /* now eval */
 156   switch (parse->num) {
 157     case EXPR_NOT:
 158       if (!ll) status = 1;
 159       break;
 160     case EXPR_AND:
 161       if (ll && lr) status = 1;
 162       break;
 163     case EXPR_OR:
 164       if (ll || lr) status = 1;
 165       break;
 166     case EXPR_IN:
 167       /* "a in b": make sure each of ll is equal to something in lr */
 168       for (t = ll; t; t = list_next(t)) {
 169         for (s = lr; s; s = list_next(s)) if (strcmp(t->string, s->string) == 0) break;
 170         if (!s) break;
 171       }
 172       /* No more ll? success */
 173       if (!t) status = 1;
 174       break;
 175     case EXPR_EXISTS:
 176       if (lcmp(ll, L0) != 0) status = 1;
 177       break;
 178     case EXPR_EQUALS:
 179       if (lcmp(ll, lr) == 0) status = 1;
 180       break;
 181     case EXPR_NOTEQ:
 182       if (lcmp(ll, lr) != 0) status = 1;
 183       break;
 184     case EXPR_LESS:
 185       if (lcmp(ll, lr) < 0) status = 1;
 186       break;
 187     case EXPR_LESSEQ:
 188       if (lcmp(ll, lr) <= 0) status = 1;
 189       break;
 190     case EXPR_MORE:
 191       if (lcmp(ll, lr) > 0) status = 1;
 192       break;
 193     case EXPR_MOREEQ:
 194       if (lcmp(ll, lr) >= 0) status = 1;
 195       break;
 196   }
 197   if (DEBUG_IF) {
 198     debug_compile(0, "if");
 199     list_print(ll);
 200     printf("(%d) ", status);
 201     list_print(lr);
 202     printf("\n");
 203   }
 204   /* find something to return */
 205   /* in odd circumstances (like "" = "") we'll have to return a new string */
 206   if (!status) t = 0;
 207   else if (ll) t = ll, ll = 0;
 208   else if (lr) t = lr, lr = 0;
 209   else t = list_new(L0, "1", 0);
 210   if (ll) list_free(ll);
 211   if (lr) list_free(lr);
 212   return t;
 213 }
 214
 215
 216 /*
 217  * compile_foreach() - compile the "for x in y" statement
 218  *
 219  * Compile_foreach() resets the given variable name to each specified
 220  * value, executing the commands enclosed in braces for each iteration.
 221  *
 222  *  parse->string  index variable
 223  *  parse->left    variable values
 224  *  parse->right   rule to compile
 225  */
 226 LIST *compile_foreach (PARSE *p, LOL *args, int *jmp) {
 227   LIST *nv = (*p->left->func)(p->left, args, jmp);
 228   LIST *result = 0;
 229   LIST *l;
 230   //
 231   /* for each value for var */
 232   for (l = nv; l && *jmp == JMP_NONE; l = list_next(l)) {
 233     /* reset $(p->string) for each val */
 234     var_set(p->string, list_new(L0, l->string, 1), VAR_SET);
 235     /* keep only last result */
 236     list_free(result);
 237     result = (*p->right->func)(p->right, args, jmp);
 238     /* continue loop? */
 239     if (*jmp == JMP_CONTINUE) *jmp = JMP_NONE;
 240   }
 241   /* here by break/continue? */
 242   if (*jmp == JMP_BREAK || *jmp == JMP_CONTINUE) *jmp = JMP_NONE;
 243   list_free(nv);
 244   /* returns result of last loop */
 245   return result;
 246 }
 247
 248
 249 /*
 250  * compile_if() - compile 'if' rule
 251  *
 252  *  parse->left   condition tree
 253  *  parse->right  then tree
 254  *  parse->third  else tree
 255  */
 256 LIST *compile_if (PARSE *p, LOL *args, int *jmp) {
 257   LIST *l = (*p->left->func)(p->left, args, jmp);
 258   //
 259   p = l?p->right:p->third;
 260   list_free(l);
 261   return (*p->func)(p, args, jmp);
 262 }
 263
 264
 265 /*
 266  * compile_include() - support for 'include' - call include() on file
 267  *
 268  *  parse->left list of files to include (can only do 1)
 269  */
 270 LIST *compile_include (PARSE *parse, LOL *args, int *jmp) {
 271   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 272   //
 273   if (DEBUG_COMPILE) {
 274     debug_compile(0, "include");
 275     list_print(nt);
 276     printf("\n");
 277   }
 278   if (nt) {
 279     TARGET *t = bindtarget(nt->string);
 280     /* bind the include file under the influence of "on-target" variables */
 281     /* though they are targets, include files are not built with make() */
 282     /* needn't copysettings(), as search sets no vars */
 283     pushsettings(t->settings);
 284     t->boundname = search(t->name, &t->time);
 285     popsettings(t->settings);
 286     /* don't parse missing file if NOCARE set */
 287     if (t->time || !(t->flags & T_FLAG_NOCARE)) parse_file(t->boundname);
 288   }
 289   list_free(nt);
 290   return L0;
 291 }
 292
 293
 294 /*
 295  * compile_list() - expand and return a list
 296  *
 297  *  parse->string - character string to expand
 298  */
 299 LIST *compile_list (PARSE *parse, LOL *args, int *jmp) {
 300   /* voodoo 1 means: s is a copyable string */
 301   const char *s = parse->string;
 302   return var_expand(L0, s, s+strlen(s), args, 1);
 303 }
 304
 305
 306 /*
 307  * compile_local() - declare (and set) local variables
 308  *
 309  *  parse->left   list of variables
 310  *  parse->right  list of values
 311  *  parse->third  rules to execute
 312  */
 313 LIST *compile_local (PARSE *parse, LOL *args, int *jmp) {
 314   LIST *l;
 315   SETTINGS *s = 0;
 316   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 317   LIST *ns = (*parse->right->func)(parse->right, args, jmp);
 318   LIST *result;
 319   //
 320   if (DEBUG_COMPILE) {
 321     debug_compile(0, "local");
 322     list_print(nt);
 323     printf(" = ");
 324     list_print(ns);
 325     printf("\n");
 326   }
 327   /* initial value is ns */
 328   for (l = nt; l; l = list_next(l)) s = addsettings(s, 0, l->string, list_copy((LIST *)0, ns));
 329   list_free(ns);
 330   list_free(nt);
 331   /* note that callees of the current context get this "local" */
 332   /* variable, making it not so much local as layered */
 333   pushsettings(s);
 334   result = (*parse->third->func)(parse->third, args, jmp);
 335   popsettings(s);
 336   freesettings(s);
 337   return result;
 338 }
 339
 340
 341 /*
 342  * compile_null() - do nothing -- a stub for parsing
 343  */
 344 LIST *compile_null (PARSE *parse, LOL *args, int *jmp) {
 345   return L0;
 346 }
 347
 348
 349 /*
 350  * compile_on() - run rule under influence of on-target variables
 351  *
 352  *  parse->left target list; only first used
 353  *  parse->right  rule to run
 354  */
 355 LIST *compile_on (PARSE *parse, LOL *args, int *jmp) {
 356   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 357   LIST *result = 0;
 358   //
 359   if (DEBUG_COMPILE) {
 360     debug_compile(0, "on");
 361     list_print(nt);
 362     printf("\n");
 363   }
 364   /* copy settings, so that 'on target var on target = val' doesn't set var globally */
 365   if (nt) {
 366     TARGET *t = bindtarget(nt->string);
 367     SETTINGS *s = copysettings(t->settings);
 368     //
 369     pushsettings(s);
 370     result = (*parse->right->func)(parse->right, args, jmp);
 371     popsettings(s);
 372     freesettings(s);
 373   }
 374   list_free(nt);
 375   return result;
 376 }
 377
 378
 379 /*
 380  * compile_rule() - compile a single user defined rule
 381  *
 382  *  parse->left list of rules to run
 383  *  parse->right  parameters (list of lists) to rule, recursing left
 384  *
 385  * Wrapped around evaluate_rule() so that headers() can share it.
 386  */
 387 LIST *compile_rule (PARSE *parse, LOL *args, int *jmp) {
 388   LOL nargs[1];
 389   LIST *result = 0;
 390   LIST *ll, *l;
 391   PARSE *p;
 392   //
 393   /* list of rules to run -- normally 1! */
 394   ll = (*parse->left->func)(parse->left, args, jmp);
 395   /* build up the list of arg lists */
 396   lol_init(nargs);
 397   for (p = parse->right; p; p = p->left) lol_add(nargs, (*p->right->func)(p->right, args, jmp));
 398   /* run rules, appending results from each */
 399   for (l = ll; l; l = list_next(l)) result = evaluate_rule(l->string, nargs, result);
 400   list_free(ll);
 401   lol_free(nargs);
 402   return result;
 403 }
 404
 405
 406 /*
 407  * evaluate_rule() - execute a rule invocation
 408  */
 409 LIST *evaluate_rule (const char *rulename, LOL *args, LIST  *result) {
 410 //#ifdef OPT_EXPAND_RULE_NAMES_EXT
 411   RULE *rule;
 412   char *expanded, *c;
 413   tKString buf;
 414   //
 415   kStringNew(&buf);
 416   if (var_string(rulename, &buf, args, ' ') < 0) {
 417     kStringFree(&buf);
 418     printf("Failed to expand rule %s -- expansion too long\n", rulename);
 419     exit(EXITBAD);
 420   }
 421   expanded = kStringCStr(&buf);
 422   while (expanded[0] == ' ') ++expanded;
 423   while ((c = strrchr(expanded, ' '))) *c = '\0';
 424   if (DEBUG_COMPILE) {
 425     debug_compile(1, rulename);
 426     if (strcmp(rulename, expanded)) printf("-> %s  ", expanded);
 427     lol_print(args);
 428     printf("\n");
 429   }
 430   rule = bindrule(expanded);
 431   kStringFree(&buf);
 432 //#else
 433 /*
 434   RULE *rule = bindrule(rulename);
 435   //
 436   if (DEBUG_COMPILE) {
 437     debug_compile(1, rulename);
 438     lol_print(args);
 439     printf("\n");
 440   }
 441 */
 442 //#endif
 443   /* check traditional targets $(<) and sources $(>) */
 444   if (!rule->actions && !rule->procedure) printf("warning: unknown rule %s\n", rule->name);
 445   /* if this rule will be executed for updating the targets then construct the action for make() */
 446   if (rule->actions) {
 447     TARGETS *t;
 448     ACTION *action;
 449     //
 450     /* the action is associated with this instance of this rule */
 451     action = (ACTION *)malloc(sizeof(ACTION));
 452     memset((char *)action, '\0', sizeof(*action));
 453     action->rule = rule;
 454     action->targets = targetlist((TARGETS *)0, lol_get(args, 0));
 455     action->sources = targetlist((TARGETS *)0, lol_get(args, 1));
 456     /* append this action to the actions of each target */
 457     for (t = action->targets; t; t = t->next) t->target->actions = actionlist(t->target->actions, action);
 458   }
 459   /* now recursively compile any parse tree associated with this rule */
 460   if (rule->procedure) {
 461     PARSE *parse = rule->procedure;
 462     SETTINGS *s = 0;
 463     int jmp = JMP_NONE;
 464     LIST *l;
 465     int i;
 466     //
 467     /* build parameters as local vars */
 468     for (l = rule->params, i = 0; l; l = l->next, i++) s = addsettings(s, 0, l->string, list_copy(L0, lol_get(args, i)));
 469     /* run rule */
 470     /* bring in local params */
 471     /* refer/free to ensure rule not freed during use */
 472     parse_refer(parse);
 473     pushsettings(s);
 474     result = list_append(result, (*parse->func)(parse, args, &jmp));
 475     popsettings(s);
 476     freesettings(s);
 477     parse_free(parse);
 478   }
 479   if (DEBUG_COMPILE) debug_compile(-1, 0);
 480 //#ifdef OPT_EXPAND_RULE_NAMES_EXT
 481   kStringFree(&buf);
 482 //#endif
 483   return result;
 484 }
 485
 486
 487 /*
 488  * compile_rules() - compile a chain of rules
 489  *
 490  *  parse->left single rule
 491  *  parse->right  more compile_rules() by right-recursion
 492  */
 493 LIST *compile_rules (PARSE *parse, LOL *args, int *jmp) {
 494   /* ignore result from first statement; return the 2nd */
 495   /* optimize recursion on the right by looping */
 496   LIST *result = 0;
 497   //
 498   while (*jmp == JMP_NONE && parse->func == compile_rules) {
 499     list_free(result);
 500     result = (*parse->left->func)(parse->left, args, jmp);
 501     parse = parse->right;
 502   }
 503   if (*jmp == JMP_NONE) {
 504     list_free(result);
 505     result = (*parse->func)(parse, args, jmp);
 506   }
 507   return result;
 508 }
 509
 510
 511 /*
 512  * compile_set() - compile the "set variable" statement
 513  *
 514  *  parse->left   variable names
 515  *  parse->right  variable values
 516  *  parse->num    VAR_SET/APPEND/DEFAULT
 517  */
 518 LIST *compile_set (PARSE *parse, LOL *args, int *jmp) {
 519   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 520   LIST *ns = (*parse->right->func)(parse->right, args, jmp);
 521   LIST *l;
 522   //
 523   if (DEBUG_COMPILE) {
 524     debug_compile(0, "set");
 525     list_print(nt);
 526     printf(" %s ", set_names[parse->num]);
 527     list_print(ns);
 528     printf("\n");
 529   }
 530   /* call var_set to set variable */
 531   /* var_set keeps ns, so need to copy it */
 532   for (l = nt; l; l = list_next(l)) var_set(l->string, list_copy(L0, ns), parse->num);
 533   list_free(nt);
 534   return ns;
 535 }
 536
 537
 538 /*
 539  * compile_setcomp() - support for `rule` - save parse tree
 540  *
 541  *  parse->string  rule name
 542  *  parse->left    list of argument names
 543  *  parse->right   rules for rule
 544  */
 545 LIST *compile_setcomp (PARSE *parse, LOL *args, int *jmp) {
 546   RULE *rule = bindrule(parse->string);
 547   LIST *params = 0;
 548   PARSE *p;
 549   //
 550   /* build param list */
 551   for (p = parse->left; p; p = p->left) params = list_new(params, p->string, 1);
 552   if (DEBUG_COMPILE) {
 553     debug_compile(0, "rule");
 554     printf("%s ", parse->string);
 555     list_print(params);
 556     printf("\n");
 557   }
 558   /* free old one, if present */
 559   if (rule->procedure) parse_free(rule->procedure);
 560   if (rule->params) list_free(rule->params);
 561   rule->procedure = parse->right;
 562   rule->params = params;
 563   /* we now own this parse tree */
 564   /* don't let parse_free() release it */
 565   parse_refer(parse->right);
 566   return L0;
 567 }
 568
 569
 570 /*
 571  * compile_setexec() - support for `actions` - save execution string
 572  *
 573  *  parse->string   rule name
 574  *  parse->string1  OS command string
 575  *  parse->num      flags
 576  *  parse->left     `bind` variables
 577  *
 578  * Note that the parse flags (as defined in compile.h) are transfered
 579  * directly to the rule flags (as defined in rules.h).
 580  */
 581 LIST *compile_setexec (PARSE *parse, LOL *args, int *jmp) {
 582   RULE *rule = bindrule(parse->string);
 583   LIST *bindlist = (*parse->left->func)(parse->left, args, jmp);
 584   //
 585   /* free old one, if present */
 586   if (rule->actions) {
 587     freestr(rule->actions);
 588     list_free(rule->bindlist);
 589   }
 590   rule->actions = copystr(parse->string1);
 591   rule->bindlist = bindlist;
 592   rule->flags = parse->num;
 593   return L0;
 594 }
 595
 596
 597 /*
 598  * compile_settings() - compile the "on =" (set variable on exec) statement
 599  *
 600  *  parse->left   variable names
 601  *  parse->right  target name
 602  *  parse->third  variable value
 603  *  parse->num    VAR_SET/APPEND/DEFAULT
 604  */
 605 LIST *compile_settings (PARSE *parse, LOL *args, int *jmp) {
 606   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 607   LIST *ns = (*parse->third->func)(parse->third, args, jmp);
 608   LIST *targets = (*parse->right->func)(parse->right, args, jmp);
 609   LIST *ts;
 610   //
 611   if (DEBUG_COMPILE) {
 612     debug_compile(0, "set");
 613     list_print(nt);
 614     printf("on ");
 615     list_print(targets);
 616     printf(" %s ", set_names[parse->num]);
 617     list_print(ns);
 618     printf("\n");
 619   }
 620   /* call addsettings to save variable setting addsettings keeps ns, so need to copy it */
 621   /* pass append flag to addsettings() */
 622   for (ts = targets; ts; ts = list_next(ts)) {
 623     TARGET *t = bindtarget(ts->string);
 624     LIST *l;
 625     //
 626     for (l = nt; l; l = list_next(l)) {
 627       t->settings = addsettings(t->settings, parse->num, l->string, list_copy((LIST *)0, ns));
 628     }
 629   }
 630   list_free(nt);
 631   list_free(targets);
 632   return ns;
 633 }
 634
 635
 636 /*
 637  * compile_switch() - compile 'switch' rule
 638  *
 639  *  parse->left   switch value (only 1st used)
 640  *  parse->right  cases
 641  *
 642  *  cases->left   1st case
 643  *  cases->right  next cases
 644  *
 645  *  case->string  argument to match
 646  *  case->left    parse tree to execute
 647  */
 648 LIST *compile_switch (PARSE *parse, LOL *args, int *jmp) {
 649   LIST *nt = (*parse->left->func)(parse->left, args, jmp);
 650   LIST *result = 0;
 651   //
 652   if (DEBUG_COMPILE) {
 653     debug_compile(0, "switch");
 654     list_print(nt);
 655     printf("\n");
 656   }
 657   /* step through cases */
 658   for (parse = parse->right; parse; parse = parse->right) {
 659     if (!matchglob(parse->left->string, nt?nt->string:"")) {
 660       /* get and exec parse tree for this case */
 661       parse = parse->left->left;
 662       result = (*parse->func)(parse, args, jmp);
 663       break;
 664     }
 665   }
 666   list_free(nt);
 667   return result;
 668 }
 669
 670
 671 /*
 672  * compile_while() - compile 'while' rule
 673  *
 674  *  parse->left   condition tree
 675  *  parse->right    execution tree
 676  */
 677 LIST *compile_while (PARSE *p, LOL *args, int *jmp) {
 678   LIST *result = 0;
 679   LIST *l;
 680   //
 681   /* returns the value from the last execution of the block */
 682   while ((*jmp == JMP_NONE ) && (l = (*p->left->func)(p->left, args, jmp))) {
 683     /* always toss while's expression */
 684     list_free(l);
 685     /* keep only last result */
 686     list_free(result);
 687     result = (*p->right->func)(p->right, args, jmp);
 688     /* continue loop? */
 689     if (*jmp == JMP_CONTINUE) *jmp = JMP_NONE;
 690   }
 691   /* here by break/continue? */
 692   if (*jmp == JMP_BREAK || *jmp == JMP_CONTINUE) *jmp = JMP_NONE;
 693   /* returns result of last loop */
 694   return result;
 695 }
 696
 697
 698 /*
 699  * debug_compile() - printf with indent to show rule expansion.
 700  */
 701 static void debug_compile (int which, const char *s) {
 702   static int level = 0;
 703   static const char indent[36] = ">>>>|>>>>|>>>>|>>>>|>>>>|>>>>|>>>>|";
 704   int i = ((1+level)*2)%35;
 705   //
 706   if (which >= 0) printf("%*.*s ", i, i, indent);
 707   if (s) printf("%s ", s);
 708   level += which;
 709 }