Antlr3.Runtime/Antlr.Runtime.Tree/CommonTree.cs

/*
 * [The "BSD licence"]
 * Copyright (c) 2005-2008 Terence Parr
 * All rights reserved.
 *
 * Conversion to C#:
 * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

namespace Antlr.Runtime.Tree {
    using ArgumentNullException = System.ArgumentNullException;
    using CLSCompliant = System.CLSCompliantAttribute;

    /** <summary>
     *  A tree node that is wrapper for a Token object.  After 3.0 release
     *  while building tree rewrite stuff, it became clear that computing
     *  parent and child index is very difficult and cumbersome.  Better to
     *  spend the space in every tree node.  If you don't want these extra
     *  fields, it's easy to cut them out in your own BaseTree subclass.
     *  </summary>
     */
    [System.Serializable]
    public class CommonTree : BaseTree {
        /** <summary>A single token is the payload</summary> */
        [CLSCompliant(false)]
        public IToken token;

        /** <summary>
         *  What token indexes bracket all tokens associated with this node
         *  and below?
         *  </summary>
         */
        protected int startIndex = -1;
        protected int stopIndex = -1;

        /** <summary>Who is the parent node of this node; if null, implies node is root</summary> */
        CommonTree parent;

        /** <summary>What index is this node in the child list? Range: 0..n-1</summary> */
        int childIndex = -1;

        public CommonTree() {
        }

        public CommonTree(CommonTree node)
            : base(node) {
            if (node == null)
                throw new ArgumentNullException("node");

            this.token = node.token;
            this.startIndex = node.startIndex;
            this.stopIndex = node.stopIndex;
        }

        public CommonTree(IToken t) {
            this.token = t;
        }

        #region Properties
        public override int CharPositionInLine {
            get {
                if (token == null || token.CharPositionInLine == -1) {
                    if (ChildCount > 0) {
                        return Children[0].CharPositionInLine;
                    }
                    return 0;
                }
                return token.CharPositionInLine;
            }
            set {
                base.CharPositionInLine = value;
            }
        }
        public override int ChildIndex {
            get {
                return childIndex;
            }
            set {
                childIndex = value;
            }
        }
        public override bool IsNil {
            get {
                return token == null;
            }
        }
        public override int Line {
            get {
                if (token == null || token.Line == 0) {
                    if (ChildCount > 0) {
                        return Children[0].Line;
                    }
                    return 0;
                }
                return token.Line;
            }
            set {
                base.Line = value;
            }
        }
        public override ITree Parent {
            get {
                return parent;
            }
            set {
                parent = (CommonTree)value;
            }
        }
        public override string Text {
            get {
                if (token == null)
                    return null;

                return token.Text;
            }
            set {
            }
        }
        public virtual IToken Token {
            get {
                return token;
            }
            set {
                token = value;
            }
        }
        public override int TokenStartIndex {
            get {
                if (startIndex == -1 && token != null) {
                    return token.TokenIndex;
                }
                return startIndex;
            }
            set {
                startIndex = value;
            }
        }
        public override int TokenStopIndex {
            get {
                if (stopIndex == -1 && token != null) {
                    return token.TokenIndex;
                }
                return stopIndex;
            }
            set {
                stopIndex = value;
            }
        }
        public override int Type {
            get {
                if (token == null)
                    return TokenTypes.Invalid;

                return token.Type;
            }
            set {
            }
        }
        #endregion

        public override ITree DupNode() {
            return new CommonTree(this);
        }

        /** <summary>
         *  For every node in this subtree, make sure it's start/stop token's
         *  are set.  Walk depth first, visit bottom up.  Only updates nodes
         *  with at least one token index &lt; 0.
         *  </summary>
         */
        public virtual void SetUnknownTokenBoundaries() {
            if (Children == null) {
                if (startIndex < 0 || stopIndex < 0) {
                    startIndex = stopIndex = token.TokenIndex;
                }
                return;
            }
            for (int i = 0; i < Children.Count; i++) {
                ((CommonTree)Children[i]).SetUnknownTokenBoundaries();
            }
            if (startIndex >= 0 && stopIndex >= 0)
                return; // already set
            if (Children.Count > 0) {
                CommonTree firstChild = (CommonTree)Children[0];
                CommonTree lastChild = (CommonTree)Children[Children.Count - 1];
                startIndex = firstChild.TokenStartIndex;
                stopIndex = lastChild.TokenStopIndex;
            }
        }

        public override string ToString() {
            if (IsNil) {
                return "nil";
            }
            if (Type == TokenTypes.Invalid) {
                return "<errornode>";
            }
            if (token == null) {
                return string.Empty;
            }
            return token.Text;
        }
    }
}