How can I test type conversion without raising exceptions?

[nat45928]

I have an application that does not have exceptions enabled. How can I test whether a type is convertible without raising an exception? For example:

json data = {
         {"boolean", true},
         {"string", "foo},
};

bool b = data.get<bool>("string"); // throws

How can I test get("string") is convertible to bs type (bool in this case)?

I've poked around and realized that I can use the .is_*() methods for basic types but objects and arrays are much more complicated. I'm hoping to find a general-ish solution if possible.

Thanks for any suggestions!

[nlohmann]

You can check the type via functions like is_string or is_boolean .

[nat45928]

Thanks for the tip!

How does that extrapolate to data structures like objects and arrays? I.e. How can I check if a json object is convertible to std::vector<std::pair<double, double>>?

I see there are a few functions relating to this like from_json_array_impl(). I was hoping there is a way to reuse some of the logic existing in the library instead of just rolling my own logic.

[nlohmann]

See #2404.