If you visit this link:

http://dlang.org/phobos/std_traits.html#isCallable

There is this paragraph:

"Detect whether T is a callable object, which can be called with the function call operator (...)."

What is this function call operator? (...) Where can i learn more about it?

On Thursday, 27 August 2015 at 15:18:24 UTC, Gary Willoughby wrote:
> What is this function call operator? (...) Where can i learn more about it?

It is the () at the end of a thing. You can overload it in a struct by writing an opCall member.

On Thu, 27 Aug 2015 15:18:22 +0000
"Gary Willoughby" <dev@nomad.so> wrote:

> If you visit this link:
> 
> http://dlang.org/phobos/std_traits.html#isCallable
> 
> There is this paragraph:
> 
> "Detect whether T is a callable object, which can be called with the function call operator (...)."
> 
> What is this function call operator? (...) Where can i learn more about it?

http://dlang.org/operatoroverloading.html#function-call

On Thursday 27 August 2015 17:18, Gary Willoughby wrote:

> What is this function call operator? (...) Where can i learn more
> about it?

http://dlang.org/operatoroverloading.html#function-call http://ddili.org/ders/d.en/operator_overloading.html#ix_operator_overloading.opCall

On Thursday, 27 August 2015 at 15:19:15 UTC, Adam D. Ruppe wrote:
> On Thursday, 27 August 2015 at 15:18:24 UTC, Gary Willoughby wrote:
>> What is this function call operator? (...) Where can i learn more about it?
>
> It is the () at the end of a thing. You can overload it in a struct by writing an opCall member.

Sorry, I mean the three dots '...' that seems to be what the documentation is referring to. Also the `isCallable` template uses it.

On Thursday, 27 August 2015 at 16:03:58 UTC, Gary Willoughby wrote:
> Sorry, I mean the three dots '...' that seems to be what the documentation is referring to. Also the `isCallable` template uses it.

That just means it can take whatever arguments. The documentation is just saying it is callable with anything; the ... is a placeholder. In the template itself, (T...) is a variadic argument list, again meaning it can take anything. (The reason isCallable does it though isn't to actually take multiple arguments, it is so it can take any *kind* of argument; a bit of a hack.)

On Thursday, 27 August 2015 at 16:12:35 UTC, Adam D. Ruppe wrote:
> On Thursday, 27 August 2015 at 16:03:58 UTC, Gary Willoughby wrote:
>> Sorry, I mean the three dots '...' that seems to be what the documentation is referring to. Also the `isCallable` template uses it.
>
> That just means it can take whatever arguments. The documentation is just saying it is callable with anything; the ... is a placeholder. In the template itself, (T...) is a variadic argument list, again meaning it can take anything. (The reason isCallable does it though isn't to actually take multiple arguments, it is so it can take any *kind* of argument; a bit of a hack.)

Ah right, I get it. Thanks.