in lib/parser.dart [148:154]
int _indexFor(int line, int column) {
for (var i = 0; i < _lineStart.length; i++) {
if (line < _lineStart[i]) return i - 1;
if (line == _lineStart[i] && column < _columnStart[i]) return i - 1;
}
return _lineStart.length - 1;
}