C# VariableDeclarationStatement类代码示例

        public override void VisitMethodDeclaration(MethodDeclaration methodDeclaration)
        {
            Guard.AgainstNullArgument("methodDeclaration", methodDeclaration);

            IEnumerable<ParameterDeclaration> parameters = methodDeclaration
                .GetChildrenByRole(Roles.Parameter)
                .Select(x => (ParameterDeclaration)x.Clone());

            var isVoid = false;
            var isAsync = methodDeclaration.Modifiers.HasFlag(Modifiers.Async);
            AstType returnType = methodDeclaration.GetChildByRole(Roles.Type).Clone();
            var type = returnType as PrimitiveType;
            if (type != null)
            {
                isVoid = string.Compare(
                    type.Keyword, "void", StringComparison.OrdinalIgnoreCase) == 0;
            }

            var methodType = new SimpleType(Identifier.Create(isVoid ? "Action" : "Func"));

            IEnumerable<AstType> types = parameters.Select(
                x => x.GetChildByRole(Roles.Type).Clone());

            methodType
                .TypeArguments
                .AddRange(types);

            if (!isVoid)
            {
                methodType.TypeArguments.Add(returnType);
            }
            var methodName = GetIdentifierName(methodDeclaration);

            var methodBody = methodDeclaration
                .GetChildrenByRole(Roles.Body)
                .FirstOrDefault();
            if (methodBody == null)
            {
                throw new NullReferenceException(string.Format("Method '{0}' has no method body", methodName));
            }
            methodBody = (BlockStatement)methodBody.Clone();

            var prototype = new VariableDeclarationStatement { Type = methodType };
            prototype.Variables.Add(new VariableInitializer(methodName));

            var anonymousMethod = new AnonymousMethodExpression(methodBody, parameters) { IsAsync = isAsync };
            var expression = new ExpressionStatement
            {
                Expression = new AssignmentExpression(
                    new IdentifierExpression(methodName), 
                    anonymousMethod)
            };

            _methods.Add(new MethodVisitorResult
            {
                MethodDefinition = methodDeclaration,
                MethodPrototype = prototype,
                MethodExpression = expression
            });
        }

		public void Run(AstNode node)
		{
			Run(node, null);
			// Declare all the variables at the end, after all the logic has run.
			// This is done so that definite assignment analysis can work on a single representation and doesn't have to be updated
			// when we change the AST.
			foreach (var v in variablesToDeclare) {
				if (v.ReplacedAssignment == null) {
					BlockStatement block = (BlockStatement)v.InsertionPoint.Parent;
					block.Statements.InsertBefore(
						v.InsertionPoint,
						new VariableDeclarationStatement((AstType)v.Type.Clone(), v.Name));
				}
			}
			// First do all the insertions, then do all the replacements. This is necessary because a replacement might remove our reference point from the AST.
			foreach (var v in variablesToDeclare) {
				if (v.ReplacedAssignment != null) {
					// We clone the right expression so that it doesn't get removed from the old ExpressionStatement,
					// which might be still in use by the definite assignment graph.
					VariableDeclarationStatement varDecl = new VariableDeclarationStatement {
						Type = (AstType)v.Type.Clone(),
						Variables = { new VariableInitializer(v.Name, v.ReplacedAssignment.Right.Detach()).CopyAnnotationsFrom(v.ReplacedAssignment) }
					};
					ExpressionStatement es = v.ReplacedAssignment.Parent as ExpressionStatement;
					if (es != null) {
						// Note: if this crashes with 'Cannot replace the root node', check whether two variables were assigned the same name
						es.ReplaceWith(varDecl.CopyAnnotationsFrom(es));
					} else {
						v.ReplacedAssignment.ReplaceWith(varDecl);
					}
				}
			}
			variablesToDeclare = null;
		}

		public override void VisitVariableDeclarationStatement(VariableDeclarationStatement variableDeclarationStatement) {
			foreach (var varNode in variableDeclarationStatement.Variables) {
				AddVariable(varNode, varNode.Name);
			}

			base.VisitVariableDeclarationStatement(variableDeclarationStatement);
		}

		void HandleVisitorVariableDeclarationStatementVisited (VariableDeclarationStatement node, InspectionData data)
		{
			foreach (var rule in policy.Rules) {
				if (rule.CheckVariableDeclaration (node, data))
					return;
			}
		}

		public void Run (RefactoringContext context)
		{
			var foreachStatement = GetForeachStatement (context);
			
			var result = context.ResolveType (foreachStatement.InExpression);
			var countProperty = GetCountProperty (result);
			
			var initializer = new VariableDeclarationStatement (new PrimitiveType ("int"), "i", new PrimitiveExpression (0));
			var id1 = new IdentifierExpression ("i");
			var id2 = id1.Clone ();
			var id3 = id1.Clone ();
			
			var forStatement = new ForStatement () {
				Initializers = { initializer },
				Condition = new BinaryOperatorExpression (id1, BinaryOperatorType.LessThan, new MemberReferenceExpression (foreachStatement.InExpression.Clone (), countProperty)),
				Iterators = { new ExpressionStatement (new UnaryOperatorExpression (UnaryOperatorType.PostIncrement, id2)) },
				EmbeddedStatement = new BlockStatement {
					new VariableDeclarationStatement (foreachStatement.VariableType.Clone (), foreachStatement.VariableName, new IndexerExpression (foreachStatement.InExpression.Clone (), id3))
				}
			};
			
			if (foreachStatement.EmbeddedStatement is BlockStatement) {
				foreach (var child in ((BlockStatement)foreachStatement.EmbeddedStatement).Statements) {
					forStatement.EmbeddedStatement.AddChild (child.Clone (), BlockStatement.StatementRole);
				}
			} else {
				forStatement.EmbeddedStatement.AddChild (foreachStatement.EmbeddedStatement.Clone (), BlockStatement.StatementRole);
			}
			
			using (var script = context.StartScript ()) {
				script.Replace (foreachStatement, forStatement);
				script.Link (initializer.Variables.First ().NameToken, id1, id2, id3);
			}
		}

 public override void VisitVariableDeclarationStatement(VariableDeclarationStatement varDecl)
 {
     //			if (CanBeSimplified(varDecl)) {
     //				varDecl.Type = new SimpleType("var");
     //			}
     // recurse into the statement (there might be a lambda with additional variable declaration statements inside there)
     base.VisitVariableDeclarationStatement(varDecl);
 }

            public override object VisitVariableDeclarationStatement(VariableDeclarationStatement variableDeclarationStatement, object data)
            {
                if ((variableDeclarationStatement.Modifiers & Modifiers.Const) == Modifiers.Const)
                {
                    UnlockWith(variableDeclarationStatement);
                }

                return base.VisitVariableDeclarationStatement(variableDeclarationStatement, data);
            }

            public override object VisitVariableDeclarationStatement(VariableDeclarationStatement variableDeclarationStatement, object data)
            {
                var anonInitializer = variableDeclarationStatement.Variables.FirstOrDefault(a => a.Initializer is AnonymousTypeCreateExpression);
                if (anonInitializer != null)
                {
                    UnlockWith(anonInitializer.Initializer);
                }

                return base.VisitVariableDeclarationStatement(variableDeclarationStatement, data);
            }

 public override void Visit(VariableDeclarationStatement expression)
 {
     if (expression.Expression != null)
     {
         outStream.Write("var {0} = {1}(", expression.Identifier, printFuncName);
         expression.Expression.Accept(this);
         outStream.Write(", \"{0}\")", TempName);
     }
     else
         outStream.Write("var {0}", expression.Identifier);
 }

			static VariableInitializer GetControlVariable(VariableDeclarationStatement variableDecl,
														  UnaryOperatorExpression condition)
			{
				var controlVariables = variableDecl.Variables.Where (
					v =>
					{
						var identifier = new IdentifierExpression (v.Name);
						return condition.Expression.Match (identifier).Success;
					}).ToList ();
				return controlVariables.Count == 1 ? controlVariables [0] : null;
			}

		void HandleVisitiorVariableDeclarationStatementVisited (VariableDeclarationStatement node, InspectionData data)
		{
			if (node.Type is PrimitiveType)
				return;
			if (node.Type is SimpleType && ((SimpleType)node.Type).Identifier == "var") 
				return;
			var severity = base.node.GetSeverity ();
			if (severity == MonoDevelop.SourceEditor.QuickTaskSeverity.None)
				return;
			//only checks for cases where the type would be obvious - assignment of new, cast, etc.
			//also check the type actually matches else the user might want to assign different subclasses later
			foreach (var v in node.Variables) {
				if (v.Initializer.IsNull)
					return;
				
				var arrCreate = v.Initializer as ArrayCreateExpression;
				if (arrCreate != null) {
					var n = node.Type as ComposedType;
					//FIXME: check the specifier compatibility
					if (n != null && n.ArraySpecifiers.Any () && n.BaseType.IsMatch (arrCreate.Type))
						continue;
					return;
				}
				var objCreate = v.Initializer as ObjectCreateExpression;
				if (objCreate != null) {
					if (objCreate.Type.IsMatch (node.Type))
						continue;
					return;
				}
				var asCast = v.Initializer as AsExpression;
				if (asCast != null) {
					if (asCast.Type.IsMatch (node.Type))
						continue;
					return;
				}
				var cast = v.Initializer as CastExpression;
				if (cast != null) {
					if (cast.Type.IsMatch (node.Type))
						continue;
					return;
				}
				return;
			}
			
			data.Add (new Result (
					new DomRegion (node.Type.StartLocation.Line, node.Type.StartLocation.Column, node.Type.EndLocation.Line, node.Type.EndLocation.Column),
					GettextCatalog.GetString ("Use implicitly typed local variable decaration"),
					severity,
					ResultCertainty.High, 
					ResultImportance.Medium,
					severity != MonoDevelop.SourceEditor.QuickTaskSeverity.Suggestion)
				);
		}

		public override void VisitVariableDeclarationStatement(VariableDeclarationStatement variableDeclarationStatement)
		{
			base.VisitVariableDeclarationStatement(variableDeclarationStatement);
			foreach (var varDecl in variableDeclarationStatement.Variables) {
				if (startLocation.IsEmpty || startLocation <= varDecl.StartLocation && varDecl.EndLocation <= endLocation) {
					var result = context.Resolve(varDecl);
					var local = result as LocalResolveResult;
					if (local != null && !UsedVariables.Contains(local.Variable))
						UsedVariables.Add(local.Variable);
				}
			}
		}

			public override void VisitVariableDeclarationStatement(VariableDeclarationStatement variableDeclarationStatement)
			{
				base.VisitVariableDeclarationStatement(variableDeclarationStatement);

				if (!(variableDeclarationStatement.Parent is BlockStatement))
					// We are somewhere weird, like a the ResourceAquisition of a using statement
					return;

				if (variableDeclarationStatement.Variables.Count > 1)
					return;

				// Start at the parent node. Presumably this is a BlockStatement
				var rootNode = variableDeclarationStatement.Parent;
				var variableInitializer = variableDeclarationStatement.Variables.First();
				var identifiers = GetIdentifiers(rootNode.Descendants, variableInitializer.Name).ToList();

				if (identifiers.Count == 0)
					// variable is not used
					return;

				AstNode deepestCommonAncestor = GetDeepestCommonAncestor(rootNode, identifiers);
				var path = GetPath(rootNode, deepestCommonAncestor);

				// Restrict path to only those where the initializer has not changed
				var firstInitializerChange = GetFirstInitializerChange(variableDeclarationStatement, path, variableInitializer.Initializer);
				if (firstInitializerChange != null) {
					path = GetPath(rootNode, firstInitializerChange);
				}

				// Restict to locations outside of blacklisted node types
				var firstBlackListedNode = (from node in path
				                            where moveTargetBlacklist.Contains(node.GetType())
				                            select node).FirstOrDefault();
				if (firstBlackListedNode != null) {
					path = GetPath(rootNode, firstBlackListedNode);
				}

				// Get the most nested possible target for the move
				Statement mostNestedFollowingStatement = null;
				for (int i = path.Count - 1; i >= 0; i--) {
					var statement = path[i] as Statement;
					if (statement != null && (IsScopeContainer(statement.Parent) || IsScopeContainer(statement))) {
						mostNestedFollowingStatement = statement;
						break;
					}
				}

				if (mostNestedFollowingStatement != null && mostNestedFollowingStatement != rootNode && mostNestedFollowingStatement.Parent != rootNode) {
					AddIssue(variableDeclarationStatement, context.TranslateString("Variable could be moved to a nested scope"),
					         GetActions(variableDeclarationStatement, mostNestedFollowingStatement));
				}
			}

 bool CanBeSimplified(VariableDeclarationStatement varDecl)
 {
     if (varDecl.Variables.Count != 1)
         return false;
     if (varDecl.Modifiers != Modifiers.None) // this line was "forgotten" in the article
         return false;
     VariableInitializer v = varDecl.Variables.Single();
     ObjectCreateExpression oce = v.Initializer as ObjectCreateExpression;
     if (oce == null)
         return false;
     //return ?AreEqualTypes?(varDecl.Type, oce.Type);
     return varDecl.Type.IsMatch(oce.Type);
 }

		public IEnumerable<CodeAction> GetActions(RefactoringContext context)
		{
			var pexpr = context.GetNode<PrimitiveExpression>();
			if (pexpr == null)
				yield break;
			var statement = context.GetNode<Statement>();
			if (statement == null) {
				yield break;
			}

			var resolveResult = context.Resolve(pexpr);

			yield return new CodeAction(context.TranslateString("Create local constant"), script => {
				string name = CreateMethodDeclarationAction.CreateBaseName(pexpr, resolveResult.Type);
				var service = (NamingConventionService)context.GetService(typeof(NamingConventionService));
				if (service != null)
					name = service.CheckName(context, name, AffectedEntity.LocalConstant);

				var initializer = new VariableInitializer(name, pexpr.Clone());
				var decl = new VariableDeclarationStatement() {
					Type = context.CreateShortType(resolveResult.Type),
					Modifiers = Modifiers.Const,
					Variables = { initializer }
				};

				script.InsertBefore(statement, decl);
				var variableUsage = new IdentifierExpression(name);
				script.Replace(pexpr, variableUsage);
				script.Link(initializer.NameToken, variableUsage);
			});

			yield return new CodeAction(context.TranslateString("Create constant field"), script => {
				string name = CreateMethodDeclarationAction.CreateBaseName(pexpr, resolveResult.Type);
				var service = (NamingConventionService)context.GetService(typeof(NamingConventionService));
				if (service != null)
					name = service.CheckName(context, name, AffectedEntity.ConstantField);

				var initializer = new VariableInitializer(name, pexpr.Clone());

				var decl = new FieldDeclaration() {
					ReturnType = context.CreateShortType(resolveResult.Type),
					Modifiers = Modifiers.Const,
					Variables = { initializer }
				};

				var variableUsage = new IdentifierExpression(name);
				script.Replace(pexpr, variableUsage);
//				script.Link(initializer.NameToken, variableUsage);
				script.InsertWithCursor(context.TranslateString("Create constant"), Script.InsertPosition.Before, decl);
			});
		}