emitter.c

编译原理的词法分析器

/*******************    emitter.c    **********************************************/
#include "global.h"
int i;
emit(t,tval)//生成输出
  int t,tval;
{

   switch(t){
    case'+':
		printf("%c\n",t);
		res[i-2]=res[i-2]+res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
	case'-': 
		printf("%c\n",t);
		res[i-2]=res[i-2]-res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
	case'*':
		printf("%c\n",t);
		res[i-2]=res[i-2]*res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
	case'/':
		printf("%c\n",t);
		res[i-2]=res[i-2]/res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
    case DIV:
		printf("DIV\n");
		res[i-2]=res[i-2]/res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
    case MOD:
		printf("MOD\n");
		res[i-2]=res[i-2] % res[i-1];
		printf("%d\n",res[i-2]);
		i--;
		break;
	case NUM:
		printf("%d\n",tval);
		res[i]=tval;
		i++;
		break;
	case ID:
		printf("%s\n",symtable[tval].lexptr);
		break;
	default:
		printf("token %d,tokenval %d\n",t,tval);
//		printf("%d\n",res[i-1]);
   }
}