utils/Burg/lex.c

   1 char rcsid_lex[] = "$Id$";
   2
   3 #include <ctype.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include "b.h"
   7 #include "fe.h"
   8 #include "gram.tab.h"
   9
  10 static char buf[BUFSIZ];
  11
  12 static int yyline = 1;
  13
  14 typedef int (*ReadFn) ARGS((void));
  15
  16 static char *StrCopy ARGS((char *));
  17 static int code_get ARGS((void));
  18 static int simple_get ARGS((void));
  19 static void ReadCharString ARGS((ReadFn, int));
  20 static void ReadCodeBlock ARGS((void));
  21 static void ReadOldComment ARGS((ReadFn));
  22
  23 static char *
  24 StrCopy(s) char *s;
  25 {
  26   char *t = (char *)zalloc(strlen(s) + 1);
  27   strcpy(t,s);
  28   return t;
  29 }
  30
  31 static int
  32 simple_get()
  33 {
  34   int ch;
  35   if ((ch = getchar()) == '\n') {
  36     yyline++;
  37   }
  38   return ch;
  39 }
  40
  41 static int
  42 code_get()
  43 {
  44   int ch;
  45   if ((ch = getchar()) == '\n') {
  46     yyline++;
  47   }
  48   if (ch != EOF) {
  49     fputc(ch, outfile);
  50   }
  51   return ch;
  52 }
  53
  54 void
  55 yypurge()
  56 {
  57   while (code_get() != EOF) ;
  58 }
  59
  60
  61 static void
  62 ReadCharString(rdfn, which) ReadFn rdfn; int which;
  63 {
  64   int ch;
  65   int backslash = 0;
  66   int firstline = yyline;
  67
  68   while ((ch = rdfn()) != EOF) {
  69     if (ch == which && !backslash) {
  70       return;
  71     }
  72     if (ch == '\\' && !backslash) {
  73       backslash = 1;
  74     } else {
  75       backslash = 0;
  76     }
  77   }
  78   yyerror1("Unexpected EOF in string on line ");
  79   fprintf(stderr, "%d\n", firstline);
  80   exit(1);
  81 }
  82
  83 static void
  84 ReadOldComment(rdfn) ReadFn rdfn;
  85 {
  86   /* will not work for comments delimiter in string */
  87
  88   int ch;
  89   int starred = 0;
  90   int firstline = yyline;
  91
  92   while ((ch = rdfn()) != EOF) {
  93     if (ch == '*') {
  94       starred = 1;
  95     } else if (ch == '/' && starred) {
  96       return;
  97     } else {
  98       starred = 0;
  99     }
 100   }
 101   yyerror1("Unexpected EOF in comment on line ");
 102   fprintf(stderr, "%d\n", firstline);
 103   exit(1);
 104 }
 105
 106 static void
 107 ReadCodeBlock()
 108 {
 109   int ch;
 110   int firstline = yyline;
 111
 112   while ((ch = getchar()) != EOF) {
 113     if (ch == '%') {
 114       ch = getchar();
 115       if (ch != '}') {
 116         yyerror("bad %%");
 117       }
 118       return;
 119     }
 120     fputc(ch, outfile);
 121     if (ch == '\n') {
 122       yyline++;
 123     }
 124     if (ch == '"' || ch == '\'') {
 125       ReadCharString(code_get, ch);
 126     } else if (ch == '/') {
 127       ch = getchar();
 128       if (ch == '*') {
 129         fputc(ch, outfile);
 130         ReadOldComment(code_get);
 131         continue;
 132       } else {
 133         ungetc(ch, stdin);
 134       }
 135     }
 136   }
 137   yyerror1("Unclosed block of C code started on line ");
 138   fprintf(stderr, "%d\n", firstline);
 139   exit(1);
 140 }
 141
 142 static int done;
 143 void
 144 yyfinished()
 145 {
 146   done = 1;
 147 }
 148
 149 int
 150 yylex()
 151 {
 152   int ch;
 153   char *ptr = buf;
 154
 155   if (done) return 0;
 156   while ((ch = getchar()) != EOF) {
 157     switch (ch) {
 158     case ' ':
 159     case '\f':
 160     case '\t':
 161       continue;
 162     case '\n':
 163       yyline++;
 164       continue;
 165     case '(':
 166     case ')':
 167     case ',':
 168     case ':':
 169     case ';':
 170     case '=':
 171       return(ch);
 172     case '/':
 173       ch = getchar();
 174       if (ch == '*') {
 175         ReadOldComment(simple_get);
 176         continue;
 177       } else {
 178         ungetc(ch, stdin);
 179         yyerror("illegal char /");
 180         continue;
 181       }
 182     case '%':
 183       ch = getchar();
 184       switch (ch) {
 185       case '%':
 186         return (K_PPERCENT);
 187       case '{':
 188         ReadCodeBlock();
 189         continue;
 190       case 's':
 191       case 'g':
 192       case 't':
 193         do {
 194           if (ptr >= &buf[BUFSIZ]) {
 195             yyerror("ID too long");
 196             return(ERROR);
 197           } else {
 198             *ptr++ = ch;
 199           }
 200           ch = getchar();
 201         } while (isalpha(ch) || isdigit(ch) || ch == '_');
 202         ungetc(ch, stdin);
 203         *ptr = '\0';
 204         if (!strcmp(buf, "term")) return K_TERM;
 205         if (!strcmp(buf, "start")) return K_START;
 206         if (!strcmp(buf, "gram")) return K_GRAM;
 207         yyerror("illegal character after %%");
 208         continue;
 209       default:
 210         yyerror("illegal character after %%");
 211         continue;
 212       }
 213     default:
 214       if (isalpha(ch) ) {
 215         do {
 216           if (ptr >= &buf[BUFSIZ]) {
 217             yyerror("ID too long");
 218             return(ERROR);
 219           } else {
 220             *ptr++ = ch;
 221           }
 222           ch = getchar();
 223         } while (isalpha(ch) || isdigit(ch) || ch == '_');
 224         ungetc(ch, stdin);
 225         *ptr = '\0';
 226         yylval.y_string = StrCopy(buf);
 227         return(ID);
 228       }
 229       if (isdigit(ch)) {
 230         int val=0;
 231         do {
 232           val *= 10;
 233           val += (ch - '0');
 234           ch = getchar();
 235         } while (isdigit(ch));
 236         ungetc(ch, stdin);
 237         yylval.y_int = val;
 238         return(INT);
 239       }
 240       yyerror1("illegal char ");
 241       fprintf(stderr, "(\\%03o)\n", ch);
 242       exit(1);
 243     }
 244   }
 245   return(0);
 246 }
 247
 248 void yyerror1(const char *str)
 249 {
 250   fprintf(stderr, "line %d: %s", yyline, str);
 251 }
 252
 253 void
 254 yyerror(const char *str)
 255 {
 256   yyerror1(str);
 257   fprintf(stderr, "\n");
 258   exit(1);
 259 }