logical.java

来自「23种设计模式JAVA实现,很好很有用的东西.」· Java 代码 · 共 35 行

package inter;
import lexer.*; import symbols.*;

public class Logical extends Expr {

   public Expr expr1, expr2;

   Logical(Token tok, Expr x1, Expr x2) {
      super(tok, null);                      // null type to start
      expr1 = x1; expr2 = x2;
      type = check(expr1.type, expr2.type);
      if (type == null ) error("type error");
   }

   public Type check(Type p1, Type p2) {
      if ( p1 == Type.Bool && p2 == Type.Bool ) return Type.Bool;
      else return null;
   }

   public Expr gen() {
      int f = newlabel(); int a = newlabel();
      Temp temp = new Temp(type);
      this.jumping(0,f);
      emit(temp.toString() + " = true");
      emit("goto L" + a);
      emitlabel(f); emit(temp.toString() + " = false");
      emitlabel(a);
      return temp;
   }

   public String toString() {
      return expr1.toString()+" "+op.toString()+" "+expr2.toString();
   }
}