Does it support std::optional or boost::optional out of the box ?

[vricosti]

Hello,

Does it support simple json conversion from std::optional<std::string> for instance ? When I test I get some errors. Thanks

[grisumbras]

Not yet, but it will be most likely added in the future.

[toonetown]

I would like to request this as well. Is this something that is being actively looked at, or is it something where a PR would be welcomed?

[vinniefalco]

What would "supporting optional" look like? Can you please give example code (using types from Boost.JSON)?

[toonetown]

As I am looking into boost::json more, I think it might be achievable outside the library by treating null values as an optional with no value. Perhaps supporting it inside the boost::json library is not necessary nor desirable.

[pdimov]

What would "supporting optional" look like?

Default implementations of value_from and value_to for std::optional<T>.

[grisumbras]

To be honest, the hardest part of implementing this feature is determining a good trait for what is and isn't an optional. I.e. is checking that the type is std::optional<T> good enough? I suspect people would expect boost::optional to be supported too.

[madmongo1]

Optionals have the member functions .has_value() and .get() That’s probably enough?

[grisumbras]

Yeah, could work

[pdimov]

boost::optional can be supported on the boost::optional side. There's no need for JSON to know about all the optionals.

[NexusHero]

Is there a timeline for this feature?

[grisumbras]

Most likely before the next Boost release (December)