Node.java

  1. /*
  2.  ***** BEGIN LICENSE BLOCK *****
  3.  * Version: EPL 1.0/GPL 2.0/LGPL 2.1
  4.  *
  5.  * The contents of this file are subject to the Eclipse Public
  6.  * License Version 1.0 (the "License"); you may not use this file
  7.  * except in compliance with the License. You may obtain a copy of
  8.  * the License at http://www.eclipse.org/legal/epl-v10.html
  9.  *
  10.  * Software distributed under the License is distributed on an "AS
  11.  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  12.  * implied. See the License for the specific language governing
  13.  * rights and limitations under the License.
  14.  *
  15.  * Copyright (C) 2001-2002 Jan Arne Petersen <jpetersen@uni-bonn.de>
  16.  * Copyright (C) 2001-2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
  17.  * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
  18.  * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
  19.  * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
  20.  * Copyright (C) 2006 Thomas Corbat <tcorbat@hsr.ch>
  21.  * 
  22.  * Alternatively, the contents of this file may be used under the terms of
  23.  * either of the GNU General Public License Version 2 or later (the "GPL"),
  24.  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  25.  * in which case the provisions of the GPL or the LGPL are applicable instead
  26.  * of those above. If you wish to allow use of your version of this file only
  27.  * under the terms of either the GPL or the LGPL, and not to allow others to
  28.  * use your version of this file under the terms of the EPL, indicate your
  29.  * decision by deleting the provisions above and replace them with the notice
  30.  * and other provisions required by the GPL or the LGPL. If you do not delete
  31.  * the provisions above, a recipient may use your version of this file under
  32.  * the terms of any one of the EPL, the GPL or the LGPL.
  33.  ***** END LICENSE BLOCK *****/
  34. package org.jruby.ast;

  36. import java.util.ArrayList;
  37. import java.util.List;

  39. import org.jruby.ParseResult;
  40. import org.jruby.ast.types.INameNode;
  41. import org.jruby.ast.visitor.AbstractNodeVisitor;
  42. import org.jruby.ast.visitor.NodeVisitor;
  43. import org.jruby.lexer.yacc.ISourcePosition;
  44. import org.jruby.lexer.yacc.ISourcePositionHolder;

  46. /**
  47.  * Base class for all Nodes in the AST
  48.  */
  49. public abstract class Node implements ISourcePositionHolder, ParseResult {    
  50.     // We define an actual list to get around bug in java integration (1387115)
  51.     static final List<Node> EMPTY_LIST = new ArrayList<Node>();
  52.     
  53.     private ISourcePosition position;

  55.     public Node(ISourcePosition position) {
  56.         this.position = position;
  57.     }

  59.     /**
  60.      * Location of this node within the source
  61.      */
  62.     public ISourcePosition getPosition() {
  63.         return position;
  64.     }

  66.     public void setPosition(ISourcePosition position) {
  67.         this.position = position;
  68.     }
  69.     
  70.     public abstract <T> T accept(NodeVisitor<T> visitor);
  71.     public abstract List<Node> childNodes();

  73.     protected static List<Node> createList(Node node) {
  74.         ArrayList<Node> list = new ArrayList<Node>(1);

  76.         list.add(node);

  78.         return list;
  79.     }

  81.     protected static List<Node> createList(Node node1, Node node2) {
  82.         ArrayList<Node> list = new ArrayList<Node>(2);

  84.         list.add(node1);
  85.         list.add(node2);

  87.         return list;
  88.     }

  90.     protected static List<Node> createList(Node node1, Node node2, Node node3) {
  91.         ArrayList<Node> list = new ArrayList<Node>(3);

  93.         list.add(node1);
  94.         list.add(node2);
  95.         list.add(node3);

  97.         return list;
  98.     }

  100.     protected static List<Node> createList(Node... nodes) {
  101.         ArrayList<Node> list = new ArrayList<Node>(nodes.length);
  102.         
  103.         for (Node node: nodes) {
  104.             if (node != null) list.add(node);
  105.         }
  106.         
  107.         return list;
  108.     }

  110.     @Override
  111.     public String toString() {
  112.         return toString(false, 0);
  113.     }

  115.     public String toString(boolean indent, int indentation) {
  116.         if (this instanceof InvisibleNode) return "";

  118.         StringBuilder builder = new StringBuilder(60);

  120.         if (indent) {
  121.             indent(indentation, builder);
  122.         }

  124.         builder.append("(").append(getNodeName());

  126.         if (this instanceof INameNode) {
  127.             builder.append(":").append(((INameNode) this).getName());
  128.         }

  130.         builder.append(" ").append(getPosition().getLine());

  132.         if (!childNodes().isEmpty() && indent) {
  133.             builder.append("\n");
  134.         }

  136.         for (Node child : childNodes()) {
  137.             if (!indent) {
  138.                 builder.append(", ");
  139.             }

  141.             if (child == null) {
  142.                 if (indent) {
  143.                     indent(indentation + 1, builder);
  144.                 }

  146.                 builder.append("null");
  147.             } else {
  148.                 if (indent && child instanceof NilImplicitNode) {
  149.                     if (indent) {
  150.                         indent(indentation + 1, builder);
  151.                     }

  153.                     builder.append(child.getClass().getSimpleName());
  154.                 } else {
  155.                     builder.append(child.toString(indent, indentation + 1));
  156.                 }
  157.             }

  159.             if (indent) {
  160.                 builder.append("\n");
  161.             }
  162.         }

  164.         if (!childNodes().isEmpty() && indent) {
  165.             indent(indentation, builder);
  166.         }

  168.         builder.append(")");

  170.         return builder.toString();
  171.     }

  173.     private static void indent(int indentation, StringBuilder builder) {
  174.         for (int n = 0; n < indentation; n++) {
  175.             builder.append("  ");
  176.         }
  177.     }

  179.     protected String getNodeName() {
  180.         String name = getClass().getName();
  181.         int i = name.lastIndexOf('.');
  182.         String nodeType = name.substring(i + 1);
  183.         return nodeType;
  184.     }

  186.     public <T extends org.jruby.ast.Node> T findFirstChild(final Class<T> nodeClass) {
  187.         return accept(new AbstractNodeVisitor<T>() {

  189.             @Override
  190.             protected T defaultVisit(Node node) {
  191.                 if (nodeClass.isAssignableFrom(node.getClass())) {
  192.                     return (T) node;
  193.                 } else {
  194.                     return visitFirstChild(node);
  195.                 }
  196.             }

  198.         });
  199.     }

  201.     /**
  202.      * @return the nodeId
  203.      */
  204.     public abstract NodeType getNodeType();

  206.     /**
  207.      * Whether the node evaluates to nil and has no side effects.
  208.      *
  209.      * @return true if nil, false otherwise
  210.      */
  211.     public boolean isNil() {
  212.         return false;
  213.     }

  215.     /**
  216.      * Check whether the given node is considered always "defined" or whether it
  217.      * has some form of definition check.
  218.      *
  219.      * @return Whether the type of node represents a possibly undefined construct
  220.      */
  221.     public boolean needsDefinitionCheck() {
  222.         return true;
  223.     }
  224. }
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