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| 1 // Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 /// Implements support for two variants of the native syntax extension. |
| 6 /// |
| 7 /// * The Dart VM variant, where native method bodies have this form: |
| 8 /// |
| 9 /// methodDeclaration() native STRING; |
| 10 /// |
| 11 /// * The Dart2js and DDC variant, where native method bodies have this form: |
| 12 /// |
| 13 /// methodDeclaration() native; |
| 14 /// |
| 15 /// This support is kept separate from parser.dart as this isn't specified in |
| 16 /// the Dart Language Specification, also we hope to remove this syntax long |
| 17 /// term and replace it with annotations and external declarations. |
| 18 library fasta.parser.dart_vm_native; |
| 19 |
| 20 import '../../scanner/token.dart' show Token; |
| 21 |
| 22 import '../scanner/token_constants.dart' show STRING_TOKEN; |
| 23 |
| 24 import '../util/link.dart' show Link; |
| 25 |
| 26 import 'parser.dart' show optional; |
| 27 |
| 28 import '../quote.dart' show unescapeString; |
| 29 |
| 30 /// When parsing a library file, we may encounter a native clause |
| 31 /// instead of a function body. This method skips such a clause. The |
| 32 /// [expectString] argument is used to choose which variant of the native clause |
| 33 /// we expect to parse. |
| 34 /// |
| 35 /// This method is designed to be called when encountering |
| 36 /// [ErrorKind.ExpectedBlockToSkip] in [Listener.handleUnrecoverableError]. |
| 37 Token skipNativeClause(Token token, bool expectString) { |
| 38 if (!optional("native", token)) return null; |
| 39 if (expectString) { |
| 40 token = token.next; |
| 41 if (token.kind != STRING_TOKEN) return null; |
| 42 } |
| 43 if (!optional(";", token.next)) return null; |
| 44 return token; |
| 45 } |
| 46 |
| 47 /// When parsing a library file, we may encounter native getters like |
| 48 /// |
| 49 /// int get length native "List_getLength"; |
| 50 /// |
| 51 /// This will result in [identifiers] being |
| 52 /// |
| 53 /// [";", '"List_getLength"', "native", "length", "get"] |
| 54 /// |
| 55 /// Similarly if [expectString] is false, we expect a getter like: |
| 56 /// |
| 57 /// int get length native; |
| 58 /// |
| 59 /// And [identifiers] being |
| 60 /// |
| 61 /// [";", "native", "length", "get"] |
| 62 /// |
| 63 /// This method returns a new list where '"List_getLength"' and "native" are |
| 64 /// removed. |
| 65 /// |
| 66 /// This method is designed to be called from [Listener.handleMemberName]. |
| 67 Link<Token> removeNativeClause(Link<Token> identifiers, bool expectString) { |
| 68 Link<Token> result = identifiers.tail; |
| 69 if (result.isEmpty) return identifiers; |
| 70 if (expectString) { |
| 71 if (result.head.kind != STRING_TOKEN) return identifiers; |
| 72 result = result.tail; |
| 73 } |
| 74 if (result.isEmpty) return identifiers; |
| 75 if (optional('native', result.head)) { |
| 76 return result.tail.prepend(identifiers.head); |
| 77 } |
| 78 return identifiers; |
| 79 } |
| 80 |
| 81 /// When the parser encounters a native clause and expects a string (like in VM |
| 82 /// and flutter patch files), this method extracts the native name in that |
| 83 /// string. |
| 84 String extractNativeMethodName(Token token) { |
| 85 return unescapeString(token.next.lexeme); |
| 86 } |
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