| // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/token.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| import 'package:linter/src/analyzer.dart'; |
| |
| const _desc = r'Avoid using braces in interpolation when not needed.'; |
| |
| const _details = r''' |
| |
| **AVOID** using braces in interpolation when not needed. |
| |
| If you're just interpolating a simple identifier, and it's not immediately |
| followed by more alphanumeric text, the `{}` can and should be omitted. |
| |
| **GOOD:** |
| ``` |
| print("Hi, $name!"); |
| ``` |
| |
| **BAD:** |
| ``` |
| print("Hi, ${name}!"); |
| ``` |
| |
| '''; |
| |
| final RegExp identifierPart = new RegExp(r'^[a-zA-Z0-9_]'); |
| |
| bool isIdentifierPart(Token token) => |
| token is StringToken && token.lexeme.startsWith(identifierPart); |
| |
| class UnnecessaryBraceInStringInterps extends LintRule { |
| UnnecessaryBraceInStringInterps() |
| : super( |
| name: 'unnecessary_brace_in_string_interps', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| AstVisitor getVisitor() => new Visitor(this); |
| } |
| |
| class Visitor extends SimpleAstVisitor { |
| LintRule rule; |
| Visitor(this.rule); |
| |
| @override |
| visitStringInterpolation(StringInterpolation node) { |
| var expressions = node.elements.where((e) => e is InterpolationExpression); |
| for (InterpolationExpression expression in expressions) { |
| if (expression.expression is SimpleIdentifier) { |
| SimpleIdentifier identifier = expression.expression; |
| Token bracket = expression.rightBracket; |
| if (bracket != null && |
| !isIdentifierPart(bracket.next) && |
| !identifier.name.contains('\$')) { |
| rule.reportLint(expression); |
| } |
| } |
| } |
| } |
| } |