PrefixDecrementNode.java :  » Web-Framework » anvil » anvil » script » expression » Java Open Source

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anvil » anvil » script » expression » PrefixDecrementNode.java
/*
 * $Id: PrefixDecrementNode.java,v 1.7 2002/09/16 08:05:05 jkl Exp $
 *
 * Copyright (c) 2002 Njet Communications Ltd. All Rights Reserved.
 *
 * Use is subject to license terms, as defined in
 * Anvil Sofware License, Version 1.1. See LICENSE 
 * file, or http://njet.org/license-1.1.txt
 */
package anvil.script.expression;

import anvil.ErrorListener;
import anvil.Location;
import anvil.core.Any;
import anvil.codec.Code;
import anvil.codec.ConstantPool;
import anvil.script.compiler.ByteCompiler;
import anvil.script.Context;
import java.io.IOException;

/**
 * class PrefixDecrementNode
 *
 * @author: Jani Lehtimki
 */
public class PrefixDecrementNode extends UnaryParent
{

  protected Location _location;


  public PrefixDecrementNode(Location location, Node child) 
  {
    super(child);
    _location = location;
  }


  public int typeOf() 
  {
    return Node.EXPR_PREFIX_DECREMENT;
  }


  public boolean isConstant()
  {
    return false;
  }


  public void check(ErrorListener listener)
  {
    super.check(listener);
    if (!_child.isUpdatable()) {
      listener.error(_location, "Right side of '--' is not an updatable expression");
    }
  }


  public void compile(ByteCompiler context, int operation)
  {
    Code code = context.getCode();
    ConstantPool pool = code.getPool();
    final Node child = _child;
    switch(child.typeOf()) {
    case Node.EXPR_VARIABLE:
      {
        child.compile(context, new Node() {
          public void compile(ByteCompiler context, int operation)
          {
            Code code = context.getCode();
            child.compile(context, GET);
            code.invokevirtual(code.getPool().addMethodRef(context.TYPE_ANY, "decrease", "()Lanvil/core/Any;"));
          }      
        });
      }
      break;
      
    case Node.EXPR_ATTRIBUTE:
      {
        AttributeNode attr = (AttributeNode)child;
        attr.getChild().compile(context, GET);
        code.astring(attr.getAttribute());
        code.aload_first();
        code.invokestatic(pool.addMethodRef(context.TYPE_CONTEXT, "predec", 
          "(Lanvil/core/Any;Ljava/lang/String;Lanvil/script/Context;)Lanvil/core/Any;"));
      }
      break;
    
    case Node.EXPR_REFERENCE:
      {
        ReferenceNode ref = (ReferenceNode)child;
        ref.getLeft().compile(context, GET);
        ref.getRight().compile(context, GET);
        code.aload_first();
        code.invokestatic(pool.addMethodRef(context.TYPE_CONTEXT, "predec", 
          "(Lanvil/core/Any;Lanvil/core/Any;Lanvil/script/Context;)Lanvil/core/Any;"));
      }
      break;

    default:
      child.compile(context, operation);
    }    
    if (operation == GET_BOOLEAN) {
      context.any2boolean();
    }  
  }
}
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