如何简洁实用编写遵循DRY原则的Dart StringBuffer写入代码

针对这段解析歌词时间的Dart代码，有几种实用简洁的优化方式，能更好地遵循DRY（Don't Repeat Yourself）原则：

方案一：正则表达式匹配+循环输出 #

用正则直接捕获时间各部分和歌词内容，再通过循环批量写入结果，彻底消除手动索引和重复的write操作：

void main() {
  final lyric = '[00:12.34]Row, row, row your boat';
  // 匹配[MM:SS.hh]格式，捕获分钟、秒、毫秒、歌词四个分组
  final timeRegex = RegExp(r'\[(\d{2}):(\d{2})\.(\d{2})\](.*)');
  final match = timeRegex.firstMatch(lyric)!;

  final buffer = StringBuffer();
  // 用列表关联标签和捕获组索引，循环生成内容
  const contentParts = [
    ('minutes:', 1),
    ('seconds:', 2),
    ('hundredths:', 3),
    ('lyrics:', 4),
  ];
  for (final (label, groupIdx) in contentParts) {
    buffer.write('$label ${match.group(groupIdx)}\n');
  }
  print(buffer.toString().trimRight());
}

方案二：提取索引逻辑+循环处理 #

如果不想用正则，可把各部分的标签、起止索引整理成列表，通过循环完成写入，消除重复的代码块：

void main() {
  final lyric = '[00:12.34]Row, row, row your boat';

  final openBracketIndex = lyric.indexOf('[');
  final colonIndex = lyric.indexOf(':');
  final dotIndex = lyric.indexOf('.');
  final endBracketIndex = lyric.indexOf(']');

  final buffer = StringBuffer();
  // 定义各部分的标签和截取范围
  final contentParts = [
    ('minutes:', openBracketIndex + 1, colonIndex),
    ('seconds:', colonIndex + 1, dotIndex),
    ('hundredths:', dotIndex + 1, endBracketIndex),
    ('lyrics:', endBracketIndex + 1, null), // null表示截取到字符串末尾
  ];
  for (final (label, start, end) in contentParts) {
    buffer.write('$label ${lyric.substring(start, end)}\n');
  }
  print(buffer.toString().trimRight());
}

方案三：多行字符串直接拼接（极简版） #

如果输出格式固定，用多行字符串直接拼接结果，代码最简洁：

void main() {
  final lyric = '[00:12.34]Row, row, row your boat';
  final match = RegExp(r'\[(\d{2}):(\d{2})\.(\d{2})\](.*)').firstMatch(lyric)!;
  
  final output = '''
minutes: ${match.group(1)}
seconds: ${match.group(2)}
hundredths: ${match.group(3)}
lyrics: ${match.group(4)}
''';
  print(output.trim());
}

这些方案的核心都是消除重复的代码块：正则方案适配性最强，循环索引方案保留原逻辑的同时简化代码，多行字符串方案适合输出格式固定的场景。

内容的提问来源于stack exchange，提问作者zex_rectooor