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 }