separatedBy<R> method

Parser<List<R>> separatedBy<R>(Parser separator, { bool includeSeparators = true, bool optionalSeparatorAtEnd = false, })

Returns a parser that consumes the receiver one or more times separated by the separator parser. The resulting parser returns a flat list of the parse results of the receiver interleaved with the parse result of the separator parser. The type parameter R defines the type of the returned list.

If the optional argument includeSeparators is set to false, then the separators are not included in the parse result. If the optional argument optionalSeparatorAtEnd is set to true the parser also accepts an optional separator at the end.

For example, the parser digit().separatedBy(char('-')) returns a parser that consumes input like '1-2-3' and returns a list of the elements and separators: ['1', '-', '2', '-', '3'].

Implementation

Parser<List<R>> separatedBy<R>(Parser separator,
    {bool includeSeparators = true, bool optionalSeparatorAtEnd = false}) {
  final parser = [
    this,
    [separator, this].toSequenceParser().star(),
    if (optionalSeparatorAtEnd) separator.optional(),
  ].toSequenceParser();
  return parser.map((list) {
    final result = <R>[];
    result.add(list[0]);
    for (final tuple in list[1]) {
      if (includeSeparators) {
        result.add(tuple[0]);
      }
      result.add(tuple[1]);
    }
    if (includeSeparators && optionalSeparatorAtEnd && list[2] != null) {
      result.add(list[2]);
    }
    return result;
  });
}