symbol.c

编译原理的词法分析器

/*********symbol.c**********************************/
#include "global.h"
#define STRMAX 999
#define SYMMAX 100
char lexemes[STRMAX];
int lastchar=-1;
struct entry symtable[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>=SYMMAX)
		error("lexmemes 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;
}