expression function

dynamic expression(
  1. String str, {
  2. bool nul = true,
})

Expression — empty Str → null; returns the value on success, null on failure (prints red-colored ERROR text).

Implementation

dynamic expression(String str, {bool nul = true}) {
  if (str.isEmpty) return null;
  final ev = _currentEvaluator;
  if (ev == null) return null;
  final v = ev.eval(str, nul: nul);
  if (ev.hasError) {
    // ignore: avoid_print
    print('<font color="#ff0000">[ERROR] $str # ${ev.lastError}</font>');
    return null;
  }
  return v;
}