errormsg.c

针对“虎书”中的tiger语言写的语法分析器 根据书中对tiger语言的描述写了72条文法

/*
 * errormsg.c - functions used in all phases of the compiler to give
 *              error messages about the Tiger program.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include "util.h"
#include "errormsg.h"


bool anyErrors= FALSE;

static string fileName = "";

static int lineNum = 1;

int EM_tokPos=0;

extern FILE *yyin;

typedef struct intList {int i; struct intList *rest;} *IntList;

static IntList intList(int i, IntList rest) 
{IntList l= checked_malloc(sizeof *l);
 l->i=i; l->rest=rest;
 return l;
}

static IntList linePos=NULL;

void EM_newline(void)
{lineNum++;
 linePos = intList(EM_tokPos, linePos);
}

void EM_error(int pos, char *message,...)
{va_list ap;
 IntList lines = linePos; 
 int num=lineNum;
 

  anyErrors=TRUE;
  while (lines && lines->i >= pos) 
       {lines=lines->rest; num--;}

  if (fileName) fprintf(stderr,"%s:",fileName);
  if (lines) fprintf(stderr,"%d.%d: ", num, pos-lines->i);
  va_start(ap,message);
  vfprintf(stderr, message, ap);
  va_end(ap);
  fprintf(stderr,"\n");

}

void EM_reset(string fname)
{
 anyErrors=FALSE; fileName=fname; lineNum=1;
 linePos=intList(0,NULL);
 yyin = fopen(fname,"r");
 if (!yyin) {EM_error(0,"cannot open"); exit(1);}
}