Question

I have this code:

namespace js0n
{

struct json
{
  typedef int json_object;

  json(){}

  json(json_object const& other)
  {
  }

  json& operator=(json_object const& other)
  {
    return *this;
  }
};

typedef json::json_object json_object;

}

The line js0n::json json(js0n::json_object()); gives a compile error.

int main()
{
  js0n::json json(js0n::json_object());

  return 0;
}

Note that I’ve culled away much of the code, as it is not responsible for the error. What am I doing wrong?

The error message:

test.cpp: In function 'int main()':
test.cpp:9:8: error: request for member 'parse' in 'json', which is of non-class type     'js0n::json(js0n::json_object (*)()) {aka js0n::json(int (*)())}'

The assignment operators i.e. (json = json_object();) is working just fine.

Answer 1

js0n::json json(js0n::json_object());

Welcome to the most vexing parse. This declares a function returning js0n::json and taking a js0n::json_object argument. To disambiguate, either add more parens, as suggested in the answer to that question, or (since you originally tagged this [c++11]), use list-initialization:

js0n::json json{js0n::json_object()};

Or

js0n::json json(js0n::json_object{});

Or

js0n::json json{js0n::json_object{}};

🙂