allPositionsWord function

Set<Position> allPositionsWord(String str, String word, { String leftOvers = '', bool continues = false, bool ignorePunctuation = false, })

Determines all of the Positions of a specified word in parameter string str.

The default behavior of the function is to count the last substring beginning with white space as a word even if it ends without a whitespace or punctuation mark. leftOvers and continues allows for incremental counting of a string over multiple calls. leftOvers is what remained of a word from a previous string and continues indicates that the string will continue, preventing the count of the last whitespace lead substring.

ignorePunctuation facilitates checking words that include symbols.

Implementation

Set<Position> allPositionsWord(String str, String word,
    {String leftOvers = '',
    bool continues = false,
    bool ignorePunctuation = false}) {
  final out = <Position>{};
  final sb = StringBuffer();
  sb.write(leftOvers);
  final chars = str.split('');
  var start = 0;
  for (var i = 0; i < chars.length; i++) {
    final ch = chars[i];
    if (ch.isWhiteSpace || (!ignorePunctuation && ch.isPunctuation)) {
      if (sb.isNotEmpty) {
        final sbString = sb.toString();
        if (sbString == word) {
          out.add(Position(start, i - 1));
        }
      }
      start = i + 1;
      sb.clear();
    } else {
      sb.write(ch);
    }
  }
  if (!continues && sb.isNotEmpty) {
    final sbString = sb.toString();
    if (sbString == word) {
      out.add(Position(start, str.length - 1));
    }
  }
  return out;
}