ICSharpCode.NRefactory.CSharp.Completion.CSharpCompletionEngine.GetExpressionAtCursor C# (CSharp) Method

		ExpressionResult GetExpressionAtCursor()
		{
			//			TextLocation memberLocation;
			//			if (currentMember != null) {
			//				memberLocation = currentMember.Region.Begin;
			//			} else if (currentType != null) {
			//				memberLocation = currentType.Region.Begin;
			//			} else {
			//				memberLocation = location;
			//			}
			var baseUnit = ParseStub("a");
			var tmpUnit = baseUnit;
			AstNode expr = baseUnit.GetNodeAt(
				location,
				n => n is IdentifierExpression || n is MemberReferenceExpression
			);
			
			if (expr == null) {
				expr = baseUnit.GetNodeAt<AstType>(location.Line, location.Column - 1);
			}
			if (expr == null)
				expr = baseUnit.GetNodeAt<Identifier>(location.Line, location.Column - 1);
			// try insertStatement
			if (expr == null && baseUnit.GetNodeAt<EmptyStatement>(
				location.Line,
				location.Column
			) != null) {
				tmpUnit = baseUnit = ParseStub("a();", false);
				expr = baseUnit.GetNodeAt<InvocationExpression>(
					location.Line,
					location.Column + 1
				); 
			}
			
			if (expr == null) {
				baseUnit = ParseStub("()");
				expr = baseUnit.GetNodeAt<IdentifierExpression>(
					location.Line,
					location.Column - 1
				); 
				if (expr == null) {
					expr = baseUnit.GetNodeAt<MemberType>(location.Line, location.Column - 1); 
				}
			}
			
			if (expr == null) {
				baseUnit = ParseStub("a", false);
				expr = baseUnit.GetNodeAt(
					location,
					n => n is IdentifierExpression || n is MemberReferenceExpression || n is CatchClause
				);
			}
			
			// try statement 
			if (expr == null) {
				expr = tmpUnit.GetNodeAt<SwitchStatement>(
					location.Line,
					location.Column - 1
				); 
				baseUnit = tmpUnit;
			}
			
			if (expr == null) {
				var block = tmpUnit.GetNodeAt<BlockStatement>(location); 
				var node = block != null ? block.Statements.LastOrDefault() : null;
				
				var forStmt = node != null ? node.PrevSibling as ForStatement : null;
				if (forStmt != null && forStmt.EmbeddedStatement.IsNull) {
					expr = forStmt;
					var id = new IdentifierExpression("stub");
					forStmt.EmbeddedStatement = new BlockStatement() { Statements = { new ExpressionStatement (id) }};
					expr = id;
					baseUnit = tmpUnit;
				}
			}
			
			if (expr == null) {
				var forStmt = tmpUnit.GetNodeAt<ForeachStatement>(
					location.Line,
					location.Column - 3
				); 
				if (forStmt != null && forStmt.EmbeddedStatement.IsNull) {
					forStmt.VariableNameToken = Identifier.Create("stub");
					expr = forStmt.VariableNameToken;
					baseUnit = tmpUnit;
				}
			}
			if (expr == null) {
				expr = tmpUnit.GetNodeAt<VariableInitializer>(
					location.Line,
					location.Column - 1
				);
				baseUnit = tmpUnit;
			}
			
			// try parameter declaration type
			if (expr == null) {
				baseUnit = ParseStub(">", false, "{}");
				expr = baseUnit.GetNodeAt<TypeParameterDeclaration>(
					location.Line,
					location.Column - 1
				); 
			}
			
			// try parameter declaration method
			if (expr == null) {
				baseUnit = ParseStub("> ()", false, "{}");
				expr = baseUnit.GetNodeAt<TypeParameterDeclaration>(
					location.Line,
					location.Column - 1
				); 
			}
			
			// try expression in anonymous type "new { sample = x$" case
			if (expr == null) {
				baseUnit = ParseStub("a", false);
				expr = baseUnit.GetNodeAt<AnonymousTypeCreateExpression>(
					location.Line,
					location.Column
				); 
				if (expr != null) {
					expr = baseUnit.GetNodeAt<Expression>(location.Line, location.Column) ?? expr;
				} 
				if (expr == null) {
					expr = baseUnit.GetNodeAt<AstType>(location.Line, location.Column);
				} 
			}
			
			if (expr == null) {
				return null;
			}
			return new ExpressionResult(expr, baseUnit);
		}