symbol.c

一个简单的识别运算的编译器程序

#include "global.h"
#include "error.c"

#define STRMAX 999
#define SYMMAX 100

char lexemes[STRMAX];
int lastchar=-1;
struct entry syntable[SYMMAX];
int lastentry=0;


int lookup(s)
     char s[];
{
	int p;
	for(p=lastentry;p>0;p=p-1)
		if(strcmp(symtable[p].lexptr,s)==0)
			return p;
		return 0;
}

int insert(s,tok)
     char s[];
     int tok;
{
		 int len;
		 len=strlen(s);
		 if(lastentry+1>=SYMMAX)
			 error("symbol table full");
		 if(lastchar+len+1>=STRMAX)
			 error("lexemes array full");
		 lastentry=lastentry+1;
		 symtable[lastentry].token=tok;
		 symtable[lastentry].lexptr=&lexemes[lastchar+1];
		 lastchar=lastchar+len+1;
		 strcpy(symtable[lastentry].lexptr,s);
		 return lastentry;
}