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
  18 # include "jam.h"
  19 # include "lists.h"
  20 # include "parse.h"
  21 # include "scan.h"
  22 # include "newstr.h"
  23
  24 static PARSE *yypsave;
  25
  26 void
  27 parse_file( const char *f )
  28 {
  29   /* Suspend scan of current file */
  30   /* and push this new file in the stream */
  31
  32   yyfparse(f);
  33
  34   /* Now parse each block of rules and execute it. */
  35   /* Execute it outside of the parser so that recursive */
  36   /* calls to yyrun() work (no recursive yyparse's). */
  37
  38   for(;;)
  39   {
  40       LOL l;
  41       PARSE *p;
  42       int jmp = 0; /* JMP_NONE */
  43
  44       /* $(<) and $(>) empty in outer scope. */
  45
  46       lol_init( &l );
  47
  48       /* Filled by yyparse() calling parse_save() */
  49
  50       yypsave = 0;
  51
  52       /* If parse error or empty parse, outta here */
  53
  54       if( yyparse() || !( p = yypsave ) )
  55     break;
  56
  57       /* Run the parse tree. */
  58
  59       list_free( (*(p->func))( p, &l, &jmp ) );
  60
  61       parse_free( p );
  62   }
  63 }
  64
  65 void
  66 parse_save( PARSE *p )
  67 {
  68   yypsave = p;
  69 }
  70
  71 PARSE *
  72 parse_make(
  73   LIST    *(*func)( PARSE *p, LOL *args, int *jmp ),
  74   PARSE *left,
  75   PARSE *right,
  76   PARSE *third,
  77   const char  *string,
  78   const char  *string1,
  79   int num )
  80 {
  81   PARSE *p = (PARSE *)malloc( sizeof( PARSE ) );
  82
  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
  92   return p;
  93 }
  94
  95 void
  96 parse_refer( PARSE *p )
  97 {
  98   ++p->refs;
  99 }
 100
 101 void
 102 parse_free( PARSE *p )
 103 {
 104   if( --p->refs )
 105       return;
 106
 107   if( p->string )
 108       freestr( p->string );
 109   if( p->string1 )
 110       freestr( p->string1 );
 111   if( p->left )
 112       parse_free( p->left );
 113   if( p->right )
 114       parse_free( p->right );
 115   if( p->third )
 116       parse_free( p->third );
 117
 118   free( (char *)p );
 119 }