Is it possible to define a class F so that
    auto f=new F();
    writeln("The value of f at 7 is ",f(7));
compiles and works as expected?

So the idea would be to be able to use notation like
    f(7)
instead of
    f.eval(7)
or something along those lines.

My guess is no, it is impossible to do this, because i can't find it on the internet or in Alexandrescu's book.

But it is also possible that everybody considers it so obvious that they just don't elaborate on it.  I'd be delighted if there were the case, at least if somebody would elaborate on it if so.

TIA for any info!

dan

On Sunday, 17 May 2015 at 18:49:40 UTC, dan wrote:
> Is it possible to define a class F so that
>     auto f=new F();
>     writeln("The value of f at 7 is ",f(7));
> compiles and works as expected?
>
> So the idea would be to be able to use notation like
>     f(7)
> instead of
>     f.eval(7)
> or something along those lines.
>
> My guess is no, it is impossible to do this, because i can't find it on the internet or in Alexandrescu's book.
>
> But it is also possible that everybody considers it so obvious that they just don't elaborate on it.  I'd be delighted if there were the case, at least if somebody would elaborate on it if so.
>
> TIA for any info!
>
> dan

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

On Sunday, 17 May 2015 at 18:58:32 UTC, Namespace wrote:
> http://dlang.org/operatoroverloading.html#function-call

Like this:

module main;

import std.stdio;

class F
{
	int opCall(int value)
	{
		return value * 2;
	}
}

void main(string[] args)
{
	auto f = new F();

	writeln("The value of f at 7 is ", f(7));
}

Awesome!!

Thanks Gary and namespace (and obviously i gotta improve my google-fu).

dan

On Sunday, 17 May 2015 at 19:40:10 UTC, Gary Willoughby wrote:
> On Sunday, 17 May 2015 at 18:58:32 UTC, Namespace wrote:
>> http://dlang.org/operatoroverloading.html#function-call
>
> Like this:
>
> module main;
>
> import std.stdio;
>
> class F
> {
> 	int opCall(int value)
> 	{
> 		return value * 2;
> 	}
> }
>
> void main(string[] args)
> {
> 	auto f = new F();
>
> 	writeln("The value of f at 7 is ", f(7));
> }

On 05/17/2015 11:49 AM, dan wrote:
> i can't find it on the internet

There is the following short section as well:


http://ddili.org/ders/d.en/operator_overloading.html#ix_operator_overloading.opCall

Ali