src/parse.c

   1 /*
   2  * Copyright 1993, 2000 Christopher Seiwald.
   3  *
   4  * This file is part of Jam - see jam.c for Copyright information.
   5  */
   6
   7 /*
   8  * parse.c - make and destroy parse trees as driven by the parser
   9  *
  10  * 09/07/00 (seiwald) - ref count on PARSE to avoid freeing when used,
  11  *    as per Matt Armstrong.
  12  * 09/11/00 (seiwald) - structure reworked to reflect that (*func)()
  13  *    returns a LIST *.
  14  * 10/22/02 (seiwald) - working return/break/continue statements
  15  * 11/04/02 (seiwald) - const-ing for string literals
  16  */
  17 #include "jam.h"
  18 #include "lists.h"
  19 #include "parse.h"
  20 #include "scan.h"
  21 #include "newstr.h"
  22
  23
  24 static PARSE *yypsave;
  25
  26
  27 #include "jamgram.c"
  28
  29
  30 static int yyparse (void) {
  31   int tk;
  32   void *pp = ParseAlloc(malloc);
  33 #ifndef NDEBUG
  34   /*ParseTrace(stderr, "**");*/
  35 #endif
  36   do {
  37     tk = yylex();
  38     Parse(pp, tk, yylval);
  39   } while (tk != 0);
  40   ParseFree(pp, free);
  41   return 0;
  42 }
  43
  44
  45 void parse_file (const char *f) {
  46   /* suspend scan of current file and push this new file in the stream */
  47   yyfparse(f);
  48   /* now parse each block of rules and execute it */
  49   /* execute it outside of the parser so that recursive */
  50   /* calls to yyrun() work (no recursive yyparse's) */
  51   for (;;) {
  52     LOL l;
  53     PARSE *p;
  54     int jmp = 0; /* JMP_NONE */
  55     /* $(<) and $(>) empty in outer scope */
  56     lol_init(&l);
  57     /* filled by yyparse() calling parse_save() */
  58     yypsave = 0;
  59     /* if parse error or empty parse, outta here */
  60     if (yyparse() || !(p = yypsave)) break;
  61     /* run the parse tree */
  62     list_free((*(p->func))(p, &l, &jmp));
  63     parse_free(p);
  64   }
  65 }
  66
  67
  68 void parse_save (PARSE *p) {
  69   yypsave = p;
  70 }
  71
  72
  73 PARSE *parse_make (
  74   LIST *(*func) (PARSE *p, LOL *args, int *jmp),
  75   PARSE *left,
  76   PARSE *right,
  77   PARSE *third,
  78   const char *string,
  79   const char *string1,
  80   int num)
  81 {
  82   PARSE *p = (PARSE *)malloc(sizeof(PARSE));
  83   p->func = func;
  84   p->left = left;
  85   p->right = right;
  86   p->third = third;
  87   p->string = string;
  88   p->string1 = string1;
  89   p->num = num;
  90   p->refs = 1;
  91   return p;
  92 }
  93
  94
  95 void parse_refer (PARSE *p) {
  96   ++p->refs;
  97 }
  98
  99
 100 void parse_free (PARSE *p) {
 101   if (--p->refs) return;
 102   if (p->string) freestr(p->string);
 103   if (p->string1) freestr(p->string1);
 104   if (p->left) parse_free(p->left);
 105   if (p->right) parse_free(p->right);
 106   if (p->third) parse_free(p->third);
 107   free((char *)p);
 108 }
 109
 110
 111 JAMFA_CONST const char *multiform_suffix (int cnt) {
 112   return (cnt == 1 ? "" : "s");
 113 }