Merge constructor

Implementation

Merge()
  : super(
      methodName: "merge",
      targetType: .map,
      arity: 1,
      function: (target, interpreter, arguments) {
        if (arguments[0] is! Map) {
          throw RuntimeError("merge() requires a Map argument");
        }
        target.addAll(arguments[0].cast<String, Object>());
        return target;
      },
    );