else.java

用java实现的编译器. 包括语法分析

package inter;
import symbols.*;
public class Else extends Stmt {
	Expr expr;
	Stmt stmt1,stmt2;
	public Else(Expr x, Stmt s1, Stmt s2){
		expr = x;
		stmt1 = s1;
		stmt2 = s2;
		if(expr.type != Type.Bool)
			expr.error("boolean required in Else");
	}	
	public void gen(int b, int a) {
		int label1 = newlabel();
		int label2 = newlabel();
		expr.jumping(0, label2);
		emitlabel(label1);
		stmt1.gen(label1, a);
		emit("goto L" + a);
		emitlabel(label2);
		stmt2.gen(label2, a);
	}
}