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1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 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. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 library string_scanner.line_scanner; | |
6 | |
7 import 'package:charcode/ascii.dart'; | 5 import 'package:charcode/ascii.dart'; |
8 | 6 |
9 import 'string_scanner.dart'; | 7 import 'string_scanner.dart'; |
10 | 8 |
11 // Note that much of this code is duplicated in eager_span_scanner.dart. | 9 // Note that much of this code is duplicated in eager_span_scanner.dart. |
12 | 10 |
13 /// A regular expression matching newlines across platforms. | 11 /// A regular expression matching newlines across platforms. |
14 final _newlineRegExp = new RegExp(r"\r\n?|\n"); | 12 final _newlineRegExp = new RegExp(r"\r\n?|\n"); |
15 | 13 |
16 /// A subclass of [StringScanner] that tracks line and column information. | 14 /// A subclass of [StringScanner] that tracks line and column information. |
17 class LineScanner extends StringScanner { | 15 class LineScanner extends StringScanner { |
18 /// The scanner's current (zero-based) line number. | 16 /// The scanner's current (zero-based) line number. |
19 int get line => _line; | 17 int get line => _line; |
20 int _line = 0; | 18 int _line = 0; |
21 | 19 |
22 /// The scanner's current (zero-based) column number. | 20 /// The scanner's current (zero-based) column number. |
23 int get column => _column; | 21 int get column => _column; |
24 int _column = 0; | 22 int _column = 0; |
25 | 23 |
26 /// The scanner's state, including line and column information. | 24 /// The scanner's state, including line and column information. |
27 /// | 25 /// |
28 /// This can be used to efficiently save and restore the state of the scanner | 26 /// This can be used to efficiently save and restore the state of the scanner |
29 /// when backtracking. A given [LineScannerState] is only valid for the | 27 /// when backtracking. A given [LineScannerState] is only valid for the |
30 /// [LineScanner] that created it. | 28 /// [LineScanner] that created it. |
| 29 /// |
| 30 /// This does not include the scanner's match information. |
31 LineScannerState get state => | 31 LineScannerState get state => |
32 new LineScannerState._(this, position, line, column); | 32 new LineScannerState._(this, position, line, column); |
33 | 33 |
34 /// Whether the current position is between a CR character and an LF | 34 /// Whether the current position is between a CR character and an LF |
35 /// charactet. | 35 /// charactet. |
36 bool get _betweenCRLF => peekChar(-1) == $cr && peekChar() == $lf; | 36 bool get _betweenCRLF => peekChar(-1) == $cr && peekChar() == $lf; |
37 | 37 |
38 set state(LineScannerState state) { | 38 set state(LineScannerState state) { |
39 if (!identical(state._scanner, this)) { | 39 if (!identical(state._scanner, this)) { |
40 throw new ArgumentError("The given LineScannerState was not returned by " | 40 throw new ArgumentError("The given LineScannerState was not returned by " |
(...skipping 27 matching lines...) Expand all Loading... |
68 } else { | 68 } else { |
69 _column = newPosition - | 69 _column = newPosition - |
70 string.lastIndexOf(_newlineRegExp, newPosition) - 1; | 70 string.lastIndexOf(_newlineRegExp, newPosition) - 1; |
71 } | 71 } |
72 } | 72 } |
73 } | 73 } |
74 | 74 |
75 LineScanner(String string, {sourceUrl, int position}) | 75 LineScanner(String string, {sourceUrl, int position}) |
76 : super(string, sourceUrl: sourceUrl, position: position); | 76 : super(string, sourceUrl: sourceUrl, position: position); |
77 | 77 |
| 78 bool scanChar(int character) { |
| 79 if (!super.scanChar(character)) return false; |
| 80 _adjustLineAndColumn(character); |
| 81 return true; |
| 82 } |
| 83 |
78 int readChar() { | 84 int readChar() { |
79 var char = super.readChar(); | 85 var character = super.readChar(); |
80 if (char == $lf || (char == $cr && peekChar() != $lf)) { | 86 _adjustLineAndColumn(character); |
| 87 return character; |
| 88 } |
| 89 |
| 90 /// Adjusts [_line] and [_column] after having consumed [character]. |
| 91 void _adjustLineAndColumn(int character) { |
| 92 if (character == $lf || (character == $cr && peekChar() != $lf)) { |
81 _line += 1; | 93 _line += 1; |
82 _column = 0; | 94 _column = 0; |
83 } else { | 95 } else { |
84 _column += 1; | 96 _column += 1; |
85 } | 97 } |
86 return char; | |
87 } | 98 } |
88 | 99 |
89 bool scan(Pattern pattern) { | 100 bool scan(Pattern pattern) { |
90 if (!super.scan(pattern)) return false; | 101 if (!super.scan(pattern)) return false; |
91 | 102 |
92 var newlines = _newlinesIn(lastMatch[0]); | 103 var newlines = _newlinesIn(lastMatch[0]); |
93 _line += newlines.length; | 104 _line += newlines.length; |
94 if (newlines.isEmpty) { | 105 if (newlines.isEmpty) { |
95 _column += lastMatch[0].length; | 106 _column += lastMatch[0].length; |
96 } else { | 107 } else { |
(...skipping 21 matching lines...) Expand all Loading... |
118 final int position; | 129 final int position; |
119 | 130 |
120 /// The zero-based line number of the scanner in this state. | 131 /// The zero-based line number of the scanner in this state. |
121 final int line; | 132 final int line; |
122 | 133 |
123 /// The zero-based column number of the scanner in this state. | 134 /// The zero-based column number of the scanner in this state. |
124 final int column; | 135 final int column; |
125 | 136 |
126 LineScannerState._(this._scanner, this.position, this.line, this.column); | 137 LineScannerState._(this._scanner, this.position, this.line, this.column); |
127 } | 138 } |
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