driver.c

针对“虎书”中的tiger语言写的词法分析器 实现了多重注释嵌套、字符串中特殊转义字符和文件结束等处理。 具体请参考Readme.txt

#include <stdio.h>
#include "util.h"
#include "errormsg.h"
#include "tokens.h"

YYSTYPE yylval;

int yylex(void); /* prototype for the lexing function */



string toknames[] = {
"ID", "STRING", "INT", "COMMA", "COLON", "SEMICOLON", "LPAREN",
"RPAREN", "LBRACK", "RBRACK", "LBRACE", "RBRACE", "DOT", "PLUS",
"MINUS", "TIMES", "DIVIDE", "EQ", "NEQ", "LT", "LE", "GT", "GE",
"AND", "OR", "ASSIGN", "ARRAY", "IF", "THEN", "ELSE", "WHILE", "FOR",
"TO", "DO", "LET", "IN", "END", "OF", "BREAK", "NIL", "FUNCTION",
"VAR", "TYPE"
};


string tokname(tok) {
  return tok<257 || tok>299 ? "BAD_TOKEN" : toknames[tok-257];
}

int main(int argc, char **argv) {

 string fname=""; int tok;
 if (argc!=2) {fprintf(stderr,"usage: a.out filename\n"); exit(1);}
 fname=argv[1];
 EM_reset(fname);
 for(;;) {
   tok=yylex();
   if (tok==0) break;
   switch(tok) {
   case ID: case STRING:
     printf("%10s %4d %s\n",tokname(tok),EM_tokPos,yylval.sval);
     break;
   case INT:
     printf("%10s %4d %d\n",tokname(tok),EM_tokPos,yylval.ival);
     break;
   default:
     printf("%10s %4d\n",tokname(tok),EM_tokPos);
   }
 }
 return 0;
}