diff options
Diffstat (limited to 'utils/Burg/lex.c')
| -rw-r--r-- | utils/Burg/lex.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/utils/Burg/lex.c b/utils/Burg/lex.c new file mode 100644 index 0000000..3d6c5af --- /dev/null +++ b/utils/Burg/lex.c @@ -0,0 +1,260 @@ +char rcsid_lex[] = "$Id$"; + +#include <ctype.h> +#include <stdio.h> +#include <string.h> +#include "b.h" +#include "fe.h" +#include "y.tab.h" + +static char buf[BUFSIZ]; + +static int yyline = 1; + +typedef int (*ReadFn) ARGS((void)); + +static char *StrCopy ARGS((char *)); +static int code_get ARGS((void)); +static int simple_get ARGS((void)); +static void ReadCharString ARGS((ReadFn, int)); +static void ReadCodeBlock ARGS((void)); +static void ReadOldComment ARGS((ReadFn)); + +static char * +StrCopy(s) char *s; +{ + char *t = (char *)zalloc(strlen(s) + 1); + strcpy(t,s); + return t; +} + +static int +simple_get() +{ + int ch; + if ((ch = getchar()) == '\n') { + yyline++; + } + return ch; +} + +static int +code_get() +{ + int ch; + if ((ch = getchar()) == '\n') { + yyline++; + } + if (ch != EOF) { + fputc(ch, outfile); + } + return ch; +} + +void +yypurge() +{ + while (code_get() != EOF) ; +} + + +static void +ReadCharString(rdfn, which) ReadFn rdfn; int which; +{ + int ch; + int backslash = 0; + int firstline = yyline; + + while ((ch = rdfn()) != EOF) { + if (ch == which && !backslash) { + return; + } + if (ch == '\\' && !backslash) { + backslash = 1; + } else { + backslash = 0; + } + } + yyerror1("Unexpected EOF in string on line "); + fprintf(stderr, "%d\n", firstline); + exit(1); +} + +static void +ReadOldComment(rdfn) ReadFn rdfn; +{ + /* will not work for comments delimiter in string */ + + int ch; + int starred = 0; + int firstline = yyline; + + while ((ch = rdfn()) != EOF) { + if (ch == '*') { + starred = 1; + } else if (ch == '/' && starred) { + return; + } else { + starred = 0; + } + } + yyerror1("Unexpected EOF in comment on line "); + fprintf(stderr, "%d\n", firstline); + exit(1); +} + +static void +ReadCodeBlock() +{ + int ch; + int firstline = yyline; + + while ((ch = getchar()) != EOF) { + if (ch == '%') { + ch = getchar(); + if (ch != '}') { + yyerror("bad %%"); + } + return; + } + fputc(ch, outfile); + if (ch == '\n') { + yyline++; + } + if (ch == '"' || ch == '\'') { + ReadCharString(code_get, ch); + } else if (ch == '/') { + ch = getchar(); + if (ch == '*') { + fputc(ch, outfile); + ReadOldComment(code_get); + continue; + } else { + ungetc(ch, stdin); + } + } + } + yyerror1("Unclosed block of C code started on line "); + fprintf(stderr, "%d\n", firstline); + exit(1); +} + +static int done; +void +yyfinished() +{ + done = 1; +} + +int +yylex() +{ + int ch; + char *ptr = buf; + + if (done) return 0; + while ((ch = getchar()) != EOF) { + switch (ch) { + case ' ': + case '\f': + case '\t': + continue; + case '\n': + yyline++; + continue; + case '(': + case ')': + case ',': + case ':': + case ';': + case '=': + return(ch); + case '/': + ch = getchar(); + if (ch == '*') { + ReadOldComment(simple_get); + continue; + } else { + ungetc(ch, stdin); + yyerror("illegal char /"); + continue; + } + case '%': + ch = getchar(); + switch (ch) { + case '%': + return (K_PPERCENT); + case '{': + ReadCodeBlock(); + continue; + case 's': + case 'g': + case 't': + do { + if (ptr >= &buf[BUFSIZ]) { + yyerror("ID too long"); + return(ERROR); + } else { + *ptr++ = ch; + } + ch = getchar(); + } while (isalpha(ch) || isdigit(ch) || ch == '_'); + ungetc(ch, stdin); + *ptr = '\0'; + if (!strcmp(buf, "term")) return K_TERM; + if (!strcmp(buf, "start")) return K_START; + if (!strcmp(buf, "gram")) return K_GRAM; + yyerror("illegal character after %%"); + continue; + default: + yyerror("illegal character after %%"); + continue; + } + default: + if (isalpha(ch) ) { + do { + if (ptr >= &buf[BUFSIZ]) { + yyerror("ID too long"); + return(ERROR); + } else { + *ptr++ = ch; + } + ch = getchar(); + } while (isalpha(ch) || isdigit(ch) || ch == '_'); + ungetc(ch, stdin); + *ptr = '\0'; + yylval.y_string = StrCopy(buf); + return(ID); + } + if (isdigit(ch)) { + int val=0; + do { + val *= 10; + val += (ch - '0'); + ch = getchar(); + } while (isdigit(ch)); + ungetc(ch, stdin); + yylval.y_int = val; + return(INT); + } + yyerror1("illegal char "); + fprintf(stderr, "(\\%03o)\n", ch); + exit(1); + } + } + return(0); +} + +void +yyerror1(str) char *str; +{ + fprintf(stderr, "line %d: %s", yyline, str); +} + +void +yyerror(str) char *str; +{ + yyerror1(str); + fprintf(stderr, "\n"); + exit(1); +} |