// Copyright 2014 The Flutter Authors. 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:flutter/material.dart'; import 'package:string_scanner/string_scanner.dart'; class SyntaxHighlighterStyle { SyntaxHighlighterStyle({ this.baseStyle, this.numberStyle, this.commentStyle, this.keywordStyle, this.stringStyle, this.punctuationStyle, this.classStyle, this.constantStyle, }); static SyntaxHighlighterStyle lightThemeStyle() { return SyntaxHighlighterStyle( baseStyle: const TextStyle(color: Color(0xFF000000)), numberStyle: const TextStyle(color: Color(0xFF1565C0)), commentStyle: const TextStyle(color: Color(0xFF9E9E9E)), keywordStyle: const TextStyle(color: Color(0xFF9C27B0)), stringStyle: const TextStyle(color: Color(0xFF43A047)), punctuationStyle: const TextStyle(color: Color(0xFF000000)), classStyle: const TextStyle(color: Color(0xFF512DA8)), constantStyle: const TextStyle(color: Color(0xFF795548)), ); } static SyntaxHighlighterStyle darkThemeStyle() { return SyntaxHighlighterStyle( baseStyle: const TextStyle(color: Color(0xFFFFFFFF)), numberStyle: const TextStyle(color: Color(0xFF1565C0)), commentStyle: const TextStyle(color: Color(0xFF9E9E9E)), keywordStyle: const TextStyle(color: Color(0xFF80CBC4)), stringStyle: const TextStyle(color: Color(0xFF009688)), punctuationStyle: const TextStyle(color: Color(0xFFFFFFFF)), classStyle: const TextStyle(color: Color(0xFF009688)), constantStyle: const TextStyle(color: Color(0xFF795548)), ); } final TextStyle? baseStyle; final TextStyle? numberStyle; final TextStyle? commentStyle; final TextStyle? keywordStyle; final TextStyle? stringStyle; final TextStyle? punctuationStyle; final TextStyle? classStyle; final TextStyle? constantStyle; } abstract class SyntaxHighlighter { TextSpan format(String src); } class DartSyntaxHighlighter extends SyntaxHighlighter { DartSyntaxHighlighter([this._style]) { _spans = <_HighlightSpan>[]; _style ??= SyntaxHighlighterStyle.darkThemeStyle(); } SyntaxHighlighterStyle? _style; static const List<String> _keywords = <String>[ 'abstract', 'as', 'assert', 'async', 'await', 'break', 'case', 'catch', 'class', 'const', 'continue', 'default', 'deferred', 'do', 'dynamic', 'else', 'enum', 'export', 'external', 'extends', 'factory', 'false', 'final', 'finally', 'for', 'get', 'if', 'implements', 'import', 'in', 'is', 'library', 'new', 'null', 'operator', 'part', 'rethrow', 'return', 'set', 'static', 'super', 'switch', 'sync', 'this', 'throw', 'true', 'try', 'typedef', 'var', 'void', 'while', 'with', 'yield', ]; static const List<String> _builtInTypes = <String>[ 'int', 'double', 'num', 'bool', ]; String? _src; late StringScanner _scanner; late List<_HighlightSpan> _spans; @override TextSpan format(String? src) { _src = src; _scanner = StringScanner(_src!); if (_generateSpans()) { // Successfully parsed the code final List<TextSpan> formattedText = <TextSpan>[]; int currentPosition = 0; for (final _HighlightSpan span in _spans) { if (currentPosition != span.start) { formattedText.add(TextSpan(text: _src!.substring(currentPosition, span.start))); } formattedText.add(TextSpan(style: span.textStyle(_style), text: span.textForSpan(_src!))); currentPosition = span.end; } if (currentPosition != _src!.length) { formattedText.add(TextSpan(text: _src!.substring(currentPosition, _src!.length))); } return TextSpan(style: _style!.baseStyle, children: formattedText); } else { // Parsing failed, return with only basic formatting return TextSpan(style: _style!.baseStyle, text: src); } } bool _generateSpans() { int lastLoopPosition = _scanner.position; while (!_scanner.isDone) { // Skip White space _scanner.scan(RegExp(r'\s+')); // Block comments if (_scanner.scan(RegExp(r'/\*(.|\n)*\*/'))) { _spans.add(_HighlightSpan( _HighlightType.comment, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Line comments if (_scanner.scan('//')) { final int startComment = _scanner.lastMatch!.start; bool eof = false; int endComment; if (_scanner.scan(RegExp(r'.*\n'))) { endComment = _scanner.lastMatch!.end - 1; } else { eof = true; endComment = _src!.length; } _spans.add(_HighlightSpan( _HighlightType.comment, startComment, endComment, )); if (eof) { break; } continue; } // Raw r"String" if (_scanner.scan(RegExp(r'r".*"'))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Raw r'String' if (_scanner.scan(RegExp(r"r'.*'"))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Multiline """String""" if (_scanner.scan(RegExp(r'"""(?:[^"\\]|\\(.|\n))*"""'))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Multiline '''String''' if (_scanner.scan(RegExp(r"'''(?:[^'\\]|\\(.|\n))*'''"))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // "String" if (_scanner.scan(RegExp(r'"(?:[^"\\]|\\.)*"'))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // 'String' if (_scanner.scan(RegExp(r"'(?:[^'\\]|\\.)*'"))) { _spans.add(_HighlightSpan( _HighlightType.string, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Double if (_scanner.scan(RegExp(r'\d+\.\d+'))) { _spans.add(_HighlightSpan( _HighlightType.number, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Integer if (_scanner.scan(RegExp(r'\d+'))) { _spans.add(_HighlightSpan( _HighlightType.number, _scanner.lastMatch!.start, _scanner.lastMatch!.end) ); continue; } // Punctuation if (_scanner.scan(RegExp(r'[\[\]{}().!=<>&\|\?\+\-\*/%\^~;:,]'))) { _spans.add(_HighlightSpan( _HighlightType.punctuation, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Meta data if (_scanner.scan(RegExp(r'@\w+'))) { _spans.add(_HighlightSpan( _HighlightType.keyword, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); continue; } // Words if (_scanner.scan(RegExp(r'\w+'))) { _HighlightType? type; String word = _scanner.lastMatch![0]!; if (word.startsWith('_')) { word = word.substring(1); } if (_keywords.contains(word)) { type = _HighlightType.keyword; } else if (_builtInTypes.contains(word)) { type = _HighlightType.keyword; } else if (_firstLetterIsUpperCase(word)) { type = _HighlightType.klass; } else if (word.length >= 2 && word.startsWith('k') && _firstLetterIsUpperCase(word.substring(1))) { type = _HighlightType.constant; } if (type != null) { _spans.add(_HighlightSpan( type, _scanner.lastMatch!.start, _scanner.lastMatch!.end, )); } } // Check if this loop did anything if (lastLoopPosition == _scanner.position) { // Failed to parse this file, abort gracefully return false; } lastLoopPosition = _scanner.position; } _simplify(); return true; } void _simplify() { for (int i = _spans.length - 2; i >= 0; i -= 1) { if (_spans[i].type == _spans[i + 1].type && _spans[i].end == _spans[i + 1].start) { _spans[i] = _HighlightSpan( _spans[i].type, _spans[i].start, _spans[i + 1].end, ); _spans.removeAt(i + 1); } } } bool _firstLetterIsUpperCase(String str) { if (str.isNotEmpty) { final String first = str.substring(0, 1); return first == first.toUpperCase(); } return false; } } enum _HighlightType { number, comment, keyword, string, punctuation, klass, constant } class _HighlightSpan { _HighlightSpan(this.type, this.start, this.end); final _HighlightType type; final int start; final int end; String textForSpan(String src) { return src.substring(start, end); } TextStyle? textStyle(SyntaxHighlighterStyle? style) { if (type == _HighlightType.number) { return style!.numberStyle; } else if (type == _HighlightType.comment) { return style!.commentStyle; } else if (type == _HighlightType.keyword) { return style!.keywordStyle; } else if (type == _HighlightType.string) { return style!.stringStyle; } else if (type == _HighlightType.punctuation) { return style!.punctuationStyle; } else if (type == _HighlightType.klass) { return style!.classStyle; } else if (type == _HighlightType.constant) { return style!.constantStyle; } else { return style!.baseStyle; } } }