Hi,

P3420's additions to reflection seems to enable the semantics I was
contemplating for the decorator idea. The decorator syntax:

@my_decorator class MyClass { ... };

would call the conteval function my_decorator with the reflection of the
not-yet-defined class MyClass. my_decorator may use the manipulation
techniques of P3420 to inject whatever it likes instead of the original
MyClass declaration. This would work the same for other types of
declarations. The USP of the decorator syntax is that you don't pollute
the namespace with names that you are not supposed to use. With the
freedom that queue_injection offers it would be possible to add the
original declaration as well as a modified version, _or_ only add the
modified declaration. For functions this will require a metafunction
body_of or something like that to inject the manually written function body.

I don't really understand why P3420 is entitled Reflection of templates,
isn't it more about manipulating declarations (although this in itself
is more complicated for template declarations).

A function like prototype_of would work equally well for the reflection
of a regular function, right?

I noted as a drawback of only having meta::info for all reflections is
that it is non-trivial to understand which actual kind of reflection is
valid for calling the new metafunctions. I'm not saying that we should
go back to multiple types, but rather that it is important to document
which kinds of reflections are valid for each metafunction.

I'm looking forward to the SG7 discussions in Wroclaw!

Bengt


On 2024-11-14 17:51, Andrei Alexandrescu via SG7 wrote:
> Hello,
>
> Following discussions with implementers we have uploaded a revised
> version of P3420:
>
> https://wiki.edg.com/pub/Wg21wroclaw2024/SG7/p3420r1.html
>
> This is the version that will be discussed in SG7. See you soon!
>
>

-- 
Bengt Gustafsson