expr.java

用java实现的编译器. 包括语法分析

package inter;
import lexer.*;
import symbols.*;
public class Expr extends Node {
	public Token op;
	public Type type;
	Expr(Token tok, Type p) {
		op = tok;
		type = p;
	}
	public Expr gen() { return this;}
	public Expr reduce() { return this;}
	public void jumping(int t,int f) {
		emitjumps(toString(), t, f);
	}
	public void emitjumps(String test, int t, int f) {
		if(t != 0 && f != 0) {
			emit("if" + test + " goto L" + t);
			emit("goto L" + f);
		}
		else if(t != 0) emit("if "+ test + " goto L" + t);
		else if(f != 0) emit("iffalse " + test + " goto L" + f);
		else ;
	}
	public String toString() { return op.toString();}
}