feature-#189

[lcsdavid]

feature-#189

• Added object constructor and assignment for json::wvalue and unit tests.
  • json::wvalue::wvalue(std::initializer_list<std::pair<std::string const, json::wvalue>>
  • json::wvalue::wvalue(std::[unordered_]map<std::string, json::wvalue> const&)
  • json::wvalue::wvalue(std::[unordered_]map<std::string, json::wvalue>&&)
  • json::wvalue::operator=(std::initializer_list<std::pair<std::string const, json::wvalue>>)
  • json::wvalue::operator=(std::[unordered_]map<std::string, json::wvalue> const&)
  • json::wvalue::operator=(std::[unordered_]map<std::string, json::wvalue>&&)

[The-EDev]

Thanks a lot, you went above and beyond doing the unit tests, I'll just look into a couple possible changes, make an example, and this will be merged :)

Thanks again for your work.

[The-EDev]

I've looked further into the code and noticed the fact that you can't exactly do something like

crow::json::wvalue value ({
{"x", 1},
{"y", "two"}
});

which to some extent makes it a comparison between

crow::json::wvalue result;
result["userid"] = userid;
result["email"] = email;
result["firstname"] = firstname;
result["lastname"] = lastname;
return result;

and

crow::json::wvalue result, userid, email, firstname, lastname;
username = 5;
email = "[email protected]";
firstname = "first_name";
lastname = "last_name";
result = {
  {"userid", userid},
  {"email", email},
  {"firstname", firstname},
  {"lastname", lastname}
};

I've seen an example of a multi-type list here and here. Another way is to just have the constructor somehow parse whatever type into json::wvalue and create the map using that. If we are to implement this feature (which I absolutely want), it would be best to implement it in a way where you could have something like the first example.

[lcsdavid]

I'll had some exemples to enlighten and show when you can and can't use implicit conversions with those constructors and assignments.
I personnaly advise against using those 'multi-types associative containers' as they add too much boiler plate, and do not solve really this question, and creates hardly understandable template error messages.

[lcsdavid]

I actually resolved the "issue", there were no implicit constructor for each supported types in json::wvalue definition.
Without those implicit conversion cannot be performed and std::initializer_list will not compile as expected.
I'll commit soon, feel free to add any remarks, I'll do changes.

[The-EDev]

Looks alright to me. I don't have as much experience as I would like though so @mrozigor do you see anything that might be problematic?

[mrozigor]

Overall it looks like a good idea to me ;) I've added a couple of comments.

[lcsdavid]

Changes done.

[The-EDev]

Thanks for your work @lcsdavid, I have to add this to the JSON Guide and make a couple changes here and there, but for now I'll merge it into master. Thanks again for doing a great job!