symbol.c

一个用flex、bison和vc开发的堆栈机

#include <math.h>
#include <malloc.h>
#include <string.h>
#include "stkmach.h"
#include "symbol.h"
#include "cc_tab.h"

struct bltin arith_fncts[] 
	= {
		"sin", sin,
		"cos", cos,
		"atan", atan,
		"ln", log,
		"exp", exp,
		"sqrt", sqrt,
		0,0
	};
struct cnst consts[] 
	= {
		"PI", 3.1415926535897932846,
		"E", 2.718281845904523536,
		"GAMMA", 0.57721566490153286060,
		"DEG", 57.29577951308232087680,
		"PHI", 1.61803398874989484820,
		0,0
	};
struct kword kwords[]
	= {
		"proc", PROC,
		"func", FUNC,
		"return", RETURN,
		"if", IF,
		"else", ELSE,
		"while", WHILE,
		"print", PRINT,
		"read", READ,
		0,0,
	};
static symrec *sym_table = (symrec *)0;
 
init_table()
{
	int i;
	symrec *ptr;
	for (i = 0; arith_fncts[i].fname != 0; i++)
	{
		ptr = putsym(arith_fncts[i].fname, BLTIN, 0);
		ptr->value.fnctptr = arith_fncts[i].bltin;
	} 
	for (i = 0; consts[i].name != 0; i++)
	{
		ptr = putsym(consts[i].name, CONST, 0);
		ptr->value.val = consts[i].val;
	} 
	for (i = 0; kwords[i].name; i++)
	{
		ptr = putsym(kwords[i].name, kwords[i].kval, 0);
	}
}

symrec* putsym(char *sym_name, int sym_type, double val)
//insert the new symbol at the begining of the sym_table
{
	symrec *ptr;
	ptr = (symrec *) malloc(sizeof(symrec));
	ptr->name = (char *)malloc(strlen(sym_name)+1);
	strcpy(ptr->name,sym_name);
	ptr->type = sym_type;
	ptr->value.val = val;
	ptr->next = (symrec *)sym_table;
	sym_table = ptr;
	return ptr;
}

symrec* getsym(char *sym_name)
{
	symrec *ptr;
	for (ptr = sym_table; ptr != 0; ptr = (symrec *)ptr->next)
		if (strcmp(ptr->name, sym_name) == 0)
			return ptr;
	return 0;
}