if.java

来自「23种设计模式JAVA实现,很好很有用的东西.」· Java 代码 · 共 19 行

package inter;
import symbols.*;

public class If extends Stmt {

   Expr expr; Stmt stmt;

   public If(Expr x, Stmt s) {
      expr = x;  stmt = s;
      if( expr.type != Type.Bool ) expr.error("boolean required in if");
   }

   public void gen(int b, int a) {
      int label = newlabel(); // label for the code for stmt
      expr.jumping(0, a);     // fall through on true, goto a on false
      emitlabel(label); stmt.gen(label, a);
   }
}