on Tue, 10 Mar 2020 19:49:01 +0000 you ("Uecker, Martin via Liaison"
<liaison_at_[hidden]>) wrote:

> Am Dienstag, den 10.03.2020, 20:16 +0100 schrieb Florian Weimer via
> Liaison:

> > Do you think there is a mechanical way to capture types and values
> > so that each macro argument is expanded exactly once? Perhaps using
> > lambdas?
>
> You can do this today using popular extensions:
>
> #define FOO(x) ({ __auto_type __x = (x); _Generic(__x, ... ); })

Yes, with lambdas and "auto" we just would have a standardized version
of that as

#define FOO(x) [](auto __x){ return _Generic(__x, ... ); }(x)

which has several advantages: a clearly marked `return` statement and
encapsulation against inadvertedly reading state from the surrounding
code.


Thanks
Jens

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