find_or is ambiguous for double and bool

[yomichi]

Calling find_or for double or bool is ambiguous while calling for int or string works well.

#include "../toml.hpp"
int main(){
  auto data = toml::parse("data.toml");
  auto N = toml::find_or(data, "int", 2);
  auto r = toml::find_or(data, "double", 1.0);
  auto b = toml::find_or(data, "bool", true);
  auto s = toml::find_or(data, "string", "foo");
}

Error message by Apple Clang is the following (GCC-9 says the similar message):

$ g++ --std=c++11 main.cpp
main.cpp:7:12: error: call to 'find_or' is ambiguous
  auto r = toml::find_or(data, "double", 1.0);
           ^~~~~~~~~~~~~
./../toml/get.hpp:588:5: note: candidate function [with T = double, $1 = nullptr]
T&& find_or(toml::value&& v, const toml::key& ky, T&& opt)
    ^
./../toml/get.hpp:661:10: note: candidate function [with T = double, $1 = nullptr]
T const& find_or(const toml::table& tab, const toml::key& ky, const T& opt)
         ^
./../toml/get.hpp:568:10: note: candidate function [with T = double, $1 = nullptr]
T const& find_or(const toml::value& v, const toml::key& ky, const T& opt)
         ^
main.cpp:8:12: error: call to 'find_or' is ambiguous
  auto b = toml::find_or(data, "bool", true);
           ^~~~~~~~~~~~~
./../toml/get.hpp:588:5: note: candidate function [with T = bool, $1 = nullptr]
T&& find_or(toml::value&& v, const toml::key& ky, T&& opt)
    ^
./../toml/get.hpp:661:10: note: candidate function [with T = bool, $1 = nullptr]
T const& find_or(const toml::table& tab, const toml::key& ky, const T& opt)
         ^
./../toml/get.hpp:568:10: note: candidate function [with T = bool, $1 = nullptr]
T const& find_or(const toml::value& v, const toml::key& ky, const T& opt)
         ^
2 errors generated.

Even if I declare data as toml::table explicitly, the problem still occurs.

Both the latest develop version (dee32e7) and the latest release (v2.3.1) of toml11 face this problem.

(By the way, could you put find_or into README?)

[ToruNiina]

Thank you for reporting!

I reproduced the error on my local environment. I think I understand why it is ambiguous, but currently don't have any idea to solve this without breaking the backward compatibility.

But I have one quick workaround. By receiving the result of toml::parse as a toml::value, the ambiguity would be resolved.

toml::value data = toml::parse("data.toml");

I will try to resolve this, but it takes some time...

[yomichi]

Thank you for giving the workaround, this seems to work in my usage!

[xgdgsc]

Thanks for the workaround, hoping it can be fixed.