anchor.diff:  /// Interface to TensorFlow-based Dart language model for next-token prediction.
   class LanguageModel {
     static const _defaultCompletions = 100;
  -  static final _numeric = RegExp(r'^\d+(.\d+)?$');
  +  static final _numeric = RegExp(r'^\d+(\.\d+)?$');
  +  static final _alphanumeric = RegExp(r"^['\w]+$");
   
     final tfl.Interpreter _interpreter;
     final Map<String, int> _word2idx;
  
positive.code:     return Map.fromEntries(entries.sublist(0, completions));
    }
  
    bool _isString(String token) {
      return token.indexOf('"') != -1 || token.indexOf("'") != -1;
    }
  
negative.code:       final lexeme =
            k < _idx2word.length ? _idx2word[k] : tokens[k - _idx2word.length];
        final sanitized = lexeme.replaceAll('"', '\'');
        if (k >= _idx2word.length && !_isAlphanumeric(sanitized)) {
          // Don't assign probability to punctuation by reference.
          return;
        }
  
        scores[sanitized] = (scores[sanitized] ?? 0.0) + v;
      });
  
  