reportError method

dynamic reportError(dynamic token)

Implementation

reportError(token) {
  var lines = [];
  var tokenDisplay =
      (token['type'] != null ? token['type'] + " token: " : "") +
          jsonEncode(token['value'] != null ? token['value'] : token);
  lines.add(this.lexer.formatError(token, "Syntax error"));
  lines.add('Unexpected ' +
      tokenDisplay +
      '. Instead, I was expecting to see one of the following:\n');
  var lastColumnIndex = this.table.length - 2;
  var lastColumn = this.table[lastColumnIndex];
  var expectantStates = lastColumn!.states.where((state) {
    if (state!.rule.symbols.isNotEmpty) {
      var nextSymbol =
          state.rule.symbols[state.dot - 1 < 0 ? 0 : state.dot - 1];
      return nextSymbol != null && !(nextSymbol is String);
    } else {
      return false;
    }
  }).toList();

  var stateStacks = expectantStates.map((state) {
    return this.buildFirstStateStack(state, []);
  }).toList();

  stateStacks.forEach((stateStack) {
    var state = stateStack[0];
    var nextSymbol =
        state.rule.symbols[state.dot - 1 < 0 ? 0 : state.dot - 1];
    var symbolDisplay = this.getSymbolDisplay(nextSymbol);
    lines.add('A ' + symbolDisplay + ' based on:');
    this.displayStateStack(stateStack, lines);
  });

  lines.add("");
  return lines.join("\n");
}