/NRefactory/ICSharpCode.NRefactory/PatternMatching/OptionalNode.cs

 1// Copyright (c) 2011-2013 AlphaSierraPapa for the SharpDevelop Team
 2// 
 3// Permission is hereby granted, free of charge, to any person obtaining a copy of this
 4// software and associated documentation files (the "Software"), to deal in the Software
 5// without restriction, including without limitation the rights to use, copy, modify, merge,
 6// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
 7// to whom the Software is furnished to do so, subject to the following conditions:
 8// 
 9// The above copyright notice and this permission notice shall be included in all copies or
10// substantial portions of the Software.
11// 
12// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
13// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
14// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
15// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
16// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
17// DEALINGS IN THE SOFTWARE.
18
19using System;
20using System.Collections.Generic;
21using System.Diagnostics;
22
23namespace ICSharpCode.NRefactory.PatternMatching
24{
25	public class OptionalNode : Pattern
26	{
27		readonly INode childNode;
28		
29		public INode ChildNode {
30			get { return childNode; }
31		}
32		
33		public OptionalNode(INode childNode)
34		{
35			if (childNode == null)
36				throw new ArgumentNullException("childNode");
37			this.childNode = childNode;
38		}
39		
40		public OptionalNode(string groupName, INode childNode) : this(new NamedNode(groupName, childNode))
41		{
42		}
43		
44		public override bool DoMatchCollection(Role role, INode pos, Match match, BacktrackingInfo backtrackingInfo)
45		{
46			backtrackingInfo.backtrackingStack.Push(new PossibleMatch(pos, match.CheckPoint()));
47			return childNode.DoMatch(pos, match);
48		}
49		
50		public override bool DoMatch(INode other, Match match)
51		{
52			if (other == null || other.IsNull)
53				return true;
54			else
55				return childNode.DoMatch(other, match);
56		}
57	}
58}