sourceInterval property

@override Interval sourceInterval

satisfy the ParseTree / SyntaxTree interface

Implementation

@override
Interval get sourceInterval {
  if (stop == null || stop!.tokenIndex < start!.tokenIndex) {
    return Interval(start!.tokenIndex, start!.tokenIndex - 1); // empty
  }
  return Interval(start!.tokenIndex, stop!.tokenIndex);
}