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 void parse_file (const char *f) {
  28   /* suspend scan of current file and push this new file in the stream */
  29   yyfparse(f);
  30   /* now parse each block of rules and execute it */
  31   /* execute it outside of the parser so that recursive */
  32   /* calls to yyrun() work (no recursive yyparse's) */
  33   for (;;) {
  34     LOL l;
  35     PARSE *p;
  36     int jmp = 0; /* JMP_NONE */
  37     /* $(<) and $(>) empty in outer scope */
  38     lol_init(&l);
  39     /* filled by yyparse() calling parse_save() */
  40     yypsave = 0;
  41     /* if parse error or empty parse, outta here */
  42     if (yyparse() || !(p = yypsave)) break;
  43     /* run the parse tree */
  44     list_free((*(p->func))(p, &l, &jmp));
  45     parse_free(p);
  46   }
  47 }
  48
  49
  50 void parse_save (PARSE *p) {
  51   yypsave = p;
  52 }
  53
  54
  55 PARSE *parse_make (
  56   LIST *(*func) (PARSE *p, LOL *args, int *jmp),
  57   PARSE *left,
  58   PARSE *right,
  59   PARSE *third,
  60   const char *string,
  61   const char *string1,
  62   int num)
  63 {
  64   PARSE *p = (PARSE *)malloc(sizeof(PARSE));
  65   p->func = func;
  66   p->left = left;
  67   p->right = right;
  68   p->third = third;
  69   p->string = string;
  70   p->string1 = string1;
  71   p->num = num;
  72   p->refs = 1;
  73   return p;
  74 }
  75
  76
  77 void parse_refer (PARSE *p) {
  78   ++p->refs;
  79 }
  80
  81
  82 void parse_free (PARSE *p) {
  83   if (--p->refs) return;
  84   if (p->string) freestr(p->string);
  85   if (p->string1) freestr(p->string1);
  86   if (p->left) parse_free(p->left);
  87   if (p->right) parse_free(p->right);
  88   if (p->third) parse_free(p->third);
  89   free((char *)p);
  90 }
  91
  92
  93 const char *multiFormSfx (int cnt) {
  94   return cnt==1?"":"s";
  95 }