C# AstNode.GetChildByRole方法代码示例

		public static ResolveResult Resolve(Lazy<ICompilation> compilation, CSharpUnresolvedFile unresolvedFile, SyntaxTree syntaxTree, TextLocation location, out AstNode node,
		                                    CancellationToken cancellationToken = default(CancellationToken))
		{
			node = syntaxTree.GetNodeAt(location);
			if (node == null || node is ArrayInitializerExpression)
				return null;
			if (CSharpAstResolver.IsUnresolvableNode(node)) {
				if (node is Identifier) {
					node = node.Parent;
				} else if (node.NodeType == NodeType.Token) {
					if (node.Parent is IndexerExpression || node.Parent is ConstructorInitializer) {
						Console.WriteLine (2);
						// There's no other place where one could hover to see the indexer's tooltip,
						// so we need to resolve it when hovering over the '[' or ']'.
						// For constructor initializer, the same applies to the 'base'/'this' token.
						node = node.Parent;
					} else {
						return null;
					}
				} else {
					// don't resolve arbitrary nodes - we don't want to show tooltips for everything
					return null;
				}
			} else {
				// It's a resolvable node.
				// However, we usually don't want to show the tooltip everywhere
				// For example, hovering with the mouse over an empty line between two methods causes
				// node==TypeDeclaration, but we don't want to show any tooltip.
				
				if (!node.GetChildByRole(Roles.Identifier).IsNull) {
					// We'll suppress the tooltip for resolvable nodes if there is an identifier that
					// could be hovered over instead:
					return null;
				}
			}
			if (node == null)
				return null;
			
			if (node.Parent is ObjectCreateExpression && node.Role == Roles.Type) {
				node = node.Parent;
			}
			
			InvocationExpression parentInvocation = null;
			if ((node is IdentifierExpression || node is MemberReferenceExpression || node is PointerReferenceExpression) && node.Role != Roles.Argument) {
				// we also need to resolve the invocation
				parentInvocation = node.Parent as InvocationExpression;
			}
			
			// TODO: I think we should provide an overload so that an existing CSharpAstResolver can be reused
			CSharpAstResolver resolver = new CSharpAstResolver(compilation.Value, syntaxTree, unresolvedFile);
			ResolveResult rr = resolver.Resolve(node, cancellationToken);
			if (rr is MethodGroupResolveResult && parentInvocation != null)
				return resolver.Resolve(parentInvocation);
			else
				return rr;
		}

		public static ResolveResult Resolve(Func<ICompilation> compilation, CSharpParsedFile parsedFile, CompilationUnit cu, TextLocation location, out AstNode node,
		                                    CancellationToken cancellationToken = default(CancellationToken))
		{
			node = cu.GetNodeAt(location);
			if (node == null)
				return null;
			if (CSharpAstResolver.IsUnresolvableNode(node)) {
				if (node is Identifier) {
					node = node.Parent;
				} else if (node.NodeType == NodeType.Token) {
					if (node.Parent is IndexerExpression || node.Parent is ConstructorInitializer) {
						// There's no other place where one could hover to see the indexer's tooltip,
						// so we need to resolve it when hovering over the '[' or ']'.
						// For constructor initializer, the same applies to the 'base'/'this' token.
						node = node.Parent;
					} else {
						return null;
					}
				} else {
					// don't resolve arbitrary nodes - we don't want to show tooltips for everything
					return null;
				}
			} else {
				// It's a resolvable node.
				// However, we usually don't want to show the tooltip everywhere
				// For example, hovering with the mouse over an empty line between two methods causes
				// node==TypeDeclaration, but we don't want to show any tooltip.
				
				if (!node.GetChildByRole(Roles.Identifier).IsNull) {
					// We'll suppress the tooltip for resolvable nodes if there is an identifier that
					// could be hovered over instead:
					return null;
				}
			}
			if (node == null)
				return null;
			
			if (node.Parent is ObjectCreateExpression && node.Role == Roles.Type) {
				node = node.Parent;
			}
			
			InvocationExpression parentInvocation = null;
			if (node is IdentifierExpression || node is MemberReferenceExpression || node is PointerReferenceExpression) {
				// we also need to resolve the invocation
				parentInvocation = node.Parent as InvocationExpression;
			}
			
			CSharpAstResolver resolver = new CSharpAstResolver(compilation(), cu, parsedFile);
			resolver.ApplyNavigator(new NodeListResolveVisitorNavigator(node), cancellationToken);
			ResolveResult rr = resolver.Resolve(node, cancellationToken);
			if (rr is MethodGroupResolveResult && parentInvocation != null)
				return resolver.Resolve(parentInvocation);
			else
				return rr;
		}

		public override void StartNode(AstNode node)
		{
			if (nodeStack.Count == 0) {
				if (IsUsingDeclaration(node)) {
					firstUsingDeclaration = !IsUsingDeclaration(node.PrevSibling);
					lastUsingDeclaration = !IsUsingDeclaration(node.NextSibling);
				} else {
					firstUsingDeclaration = false;
					lastUsingDeclaration = false;
				}
			}
			nodeStack.Push(node);
			startLocations.Push(output.Location);
			
			if (node is EntityDeclaration && node.Annotation<MemberReference>() != null && node.GetChildByRole(Roles.Identifier).IsNull)
				output.WriteDefinition("", node.Annotation<MemberReference>(), false);

			if (node.Annotation<MethodDebugSymbols>() != null) {
				symbolsStack.Push(node.Annotation<MethodDebugSymbols>());
				symbolsStack.Peek().StartLocation = startLocations.Peek();
			}
		}

		public void StartNode(AstNode node)
		{
			if (nodeStack.Count == 0) {
				if (IsUsingDeclaration(node)) {
					firstUsingDeclaration = !IsUsingDeclaration(node.PrevSibling);
					lastUsingDeclaration = !IsUsingDeclaration(node.NextSibling);
				} else {
					firstUsingDeclaration = false;
					lastUsingDeclaration = false;
				}
			}
			nodeStack.Push(node);
			startLocations.Push(output.Location);
			
			if (node is EntityDeclaration && node.Annotation<MemberReference>() != null && node.GetChildByRole(Roles.Identifier).IsNull)
				output.WriteDefinition("", node.Annotation<MemberReference>(), false);
			
			MemberMapping mapping = node.Annotation<MemberMapping>();
			if (mapping != null) {
				parentMemberMappings.Push(currentMemberMapping);
				currentMemberMapping = mapping;
			}
		}

		public static ResolveResult Resolve(Lazy<ICompilation> compilation, CSharpUnresolvedFile unresolvedFile, SyntaxTree syntaxTree, TextLocation location, out AstNode node,
		                                    CancellationToken cancellationToken = default(CancellationToken))
		{
			node = syntaxTree.GetNodeAt(location);
			if (node == null || node is ArrayInitializerExpression)
				return null;
			if (node.Parent is UsingAliasDeclaration && node.Role == UsingAliasDeclaration.AliasRole) {
				var r = new CSharpAstResolver(compilation.Value, syntaxTree, unresolvedFile);
				return r.Resolve(((UsingAliasDeclaration)node.Parent).Import, cancellationToken);
			}
			if (CSharpAstResolver.IsUnresolvableNode(node)) {
				if (node is Identifier) {
					node = node.Parent;
				} else if (node.NodeType == NodeType.Token) {
					if (node.Parent is IndexerExpression || node.Parent is ConstructorInitializer || node.Role == IndexerDeclaration.ThisKeywordRole) {
						// There's no other place where one could hover to see the indexer's tooltip,
						// so we need to resolve it when hovering over the '[' or ']'.
						// For constructor initializer, the same applies to the 'base'/'this' token.
						node = node.Parent;
					} else if (node.Parent is BinaryOperatorExpression || node.Parent is UnaryOperatorExpression) {
						// Resolve user-defined operator
						node = node.Parent;
					} else {
						return null;
					}
				} else {
					// don't resolve arbitrary nodes - we don't want to show tooltips for everything
					return null;
				}
			} else {
				// It's a resolvable node.
				// However, we usually don't want to show the tooltip everywhere
				// For example, hovering with the mouse over an empty line between two methods causes
				// node==TypeDeclaration, but we don't want to show any tooltip.
				
				if (!node.GetChildByRole(Roles.Identifier).IsNull) {
					// We'll suppress the tooltip for resolvable nodes if there is an identifier that
					// could be hovered over instead:
					return null;
				}
			}

			if (node == null)
				return null;
			if (node.Parent is ObjectCreateExpression && node.Role == Roles.Type) {
				node = node.Parent;
			} else if (node is ThisReferenceExpression && node.Parent is IndexerExpression) {
				node = node.Parent;
			}

			InvocationExpression parentInvocation = null;
			if ((node is IdentifierExpression || node is MemberReferenceExpression || node is PointerReferenceExpression) && node.Role != Roles.Argument) {
				// we also need to resolve the invocation
				parentInvocation = node.Parent as InvocationExpression;
			}
			
			// TODO: I think we should provide an overload so that an existing CSharpAstResolver can be reused
			CSharpAstResolver resolver = new CSharpAstResolver(compilation.Value, syntaxTree, unresolvedFile);
			ResolveResult rr = resolver.Resolve(node, cancellationToken);
			MethodGroupResolveResult mgrr = rr as MethodGroupResolveResult;
			if (mgrr != null) {
				// For method groups, resolve the parent invocation instead.
				if (parentInvocation != null)
					return resolver.Resolve(parentInvocation);
				if (node is Expression) {
					// If it's not an invocation, try if it's a conversion to a delegate type:
					Conversion c = resolver.GetConversion((Expression)node, cancellationToken);
					if (c.IsMethodGroupConversion)
						return new MemberResolveResult(mgrr.TargetResult, c.Method);
				}
			}
			return rr;
		}

		static bool HasNoIdentifier(AstNode node)
		{
			return 
				node.GetChildByRole(Roles.Identifier) == Roles.Identifier.NullObject &&
				node.GetChildByRole(Roles.Parameter) == Roles.Parameter.NullObject &&
				node.GetChildByRole(Roles.Argument) == Roles.Argument.NullObject &&
				node.GetChildByRole(Roles.Type) == Roles.Type.NullObject &&
				node.GetChildByRole(Roles.TargetExpression) == Roles.TargetExpression.NullObject &&
				node.GetChildByRole(Roles.TypeParameter) == Roles.TypeParameter.NullObject &&
				node.GetChildByRole(Roles.TypeArgument) == Roles.TypeArgument.NullObject &&
				node.GetChildByRole(Roles.Constraint) == Roles.Constraint.NullObject;
		}