SharpDevelop/ICSharpCode.NRefactory.CSharp/Refactoring/CodeActions/JoinDeclarationAndAssignmentAction.cs

// 
// JoinDeclarationAndAssignmentAction.cs
// 
// Author:
//      Mansheng Yang <lightyang0@gmail.com>
// 
// Copyright (c) 2012 Mansheng Yang <lightyang0@gmail.com>
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System.Linq;
using ICSharpCode.NRefactory.PatternMatching;

namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
	[ContextAction ("Join local variable declaration and assignment",
					Description = "Join local variable declaration and assignment.")]
	public class JoinDeclarationAndAssignmentAction : SpecializedCodeAction<VariableInitializer>
	{
		protected override CodeAction GetAction (RefactoringContext context, VariableInitializer node)
		{
			var variableDecl = node.Parent as VariableDeclarationStatement;
			if (variableDecl == null || !node.Initializer.IsNull)
				return null;

			var assignmentPattern = new ExpressionStatement(
				new AssignmentExpression (new IdentifierExpression (node.Name), new AnyNode ("value")));
			var nextSibling = variableDecl.GetNextSibling(n => n is Statement);
			var match = assignmentPattern.Match(nextSibling);
			if (!match.Success)
				return null;

			return new CodeAction (context.TranslateString ("Join local variable declaration and assignment"), script => {
				var jointVariableDecl = new VariableDeclarationStatement (variableDecl.Type.Clone (),
					node.Name, match.Get<Expression> ("value").First ().Clone ());
				script.Replace (nextSibling, jointVariableDecl);
				if (variableDecl.Variables.Count == 1) {
					script.Remove (variableDecl);
				} else {
					var newVariableDecl = new VariableDeclarationStatement { Type = variableDecl.Type.Clone () };
					foreach (var variable in variableDecl.Variables.Where (variable => variable != node))
						newVariableDecl.Variables.Add ((VariableInitializer) variable.Clone ());
					script.Replace (variableDecl, newVariableDecl);
				}
			}, node.NameToken);
		}
	}
}