previous method

@override int? previous(String line, [ int? start ])

Looks for the previous current pattern. start: If null the whole line is inspected. Otherwise the search starts at this index Returns null if not found or the index of the hit.

Implementation

@override
int? previous(String line, [int? start]) {
  final it = regExp.allMatches(line);
  RegExpMatch? lastMatch;
  if (it.isNotEmpty) {
    if (start == null) {
      lastMatch = it.last;
    } else {
      final bound = start + 1;
      for (var match in it) {
        if (match.end <= bound) {
          lastMatch = match;
        }
      }
    }
  }
  searchEngine.lastMatch.type = LastMatchType.regularExpr;
  searchEngine.lastMatch.regExpMatch = lastMatch;
  searchEngine.lastMatch.position.column = lastMatch?.start ?? -1;
  return lastMatch?.start;
}