Cannot get arbitrary type conversion working

[mries92]

Hey guys, I have read the steps detailed here, but cannot seem to get it working. Here is my entire program. (I have also tried it manually defining the functions, not using macros). I am using version 3.9.1.

#include "json.hpp"
#include <iostream>
#include <fstream>

using json = nlohmann::json;

struct Tile
{
	std::string name;
	NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(Tile, name);
};

int main()
{
	std::ifstream i("tiles.json", std::ifstream::in);
	json j;
	i >> j;
	auto tiles = j.get<Tile>();
}

And here are the errors being generated. I have been fiddling with this for hours now before breaking it out into a small project like this and cannot figure out if I missed anything. Please help! =]

Severity	Code	Description	Project	File	Line	Suppression State
Error (active)	E0304	no instance of overloaded function "nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::get [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool, NumberIntegerType=int64_t, NumberUnsignedType=uint64_t, NumberFloatType=double, AllocatorType=std::allocator, JSONSerializer=nlohmann::adl_serializer, BinaryType=std::vector<uint8_t, std::allocator<uint8_t>>]" matches the argument list	JsonTest	C:\Users\mries\Desktop\JsonTest\JsonTest\main.cpp	19	
Error	C2672	'nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer,std::vector<uint8_t,std::allocator<uint8_t>>>::get': no matching overloaded function found	JsonTest	C:\Users\mries\Desktop\JsonTest\JsonTest\main.cpp	19	
Error	C2783	'nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer,std::vector<uint8_t,std::allocator<uint8_t>>> nlohmann::basic_json<std::map,std::vector,std::string,bool,int64_t,uint64_t,double,std::allocator,nlohmann::adl_serializer,std::vector<uint8_t,std::allocator<uint8_t>>>::get(void) const': could not deduce template argument for '__formal'	JsonTest	C:\Users\mries\Desktop\JsonTest\JsonTest\main.cpp	19

[nlohmann]

Can you share the content of tiles.json?

[mries92]

Sure, in this case the plural is a bit of a misnomer from what I was previously trying to do. The file just contains one "Tile" object (I think).

{
    "name": "Grass"
}

If I do a cout I can see that the text is being loaded in correctly.

[nlohmann]

As described in https://github.com/nlohmann/json#simplify-your-life-with-macros:

NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE must be define outside of the class/struct, but inside its namespace.

This works:

struct Tile
{
    std::string name;
};

NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(Tile, name);

[mries92]

That did it, thank you so much! I admit my c++ knowledge is a little grainy, so I must have missed that nuance about the macro/namespaces. Thanks for the great open source library and the support!