Taking a function or delegate as argument.

[bls]

On 01/10/2012 06:53 AM, Jacob Carlborg wrote:
> On 2012-01-10 14:48, simendsjo wrote:
>> On 10.01.2012 14:43, Mike Parker wrote:
>>> On 1/10/2012 10:05 PM, simendsjo wrote:
>>>> If I want to have a method taking a callback function, I have to
>>>> specify
>>>> if it should take a function or delegate even if I don't really care.
>>>> What's the best way to accept either? I cannot see any wrapper for
>>>> something like this in std.typecons.
>>>
>>> The simple way:
>>>
>>> void callback(int i, void delegate(int) dg)
>>> {
>>> dg(i);
>>> }
>>>
>>> void callback(int i, void function(int) fn)
>>> {
>>> void wrap(int j)
>>> {
>>> function(j);
>>> }
>>> callback(i, &wrap);
>>> }
>>
>> Yeah, but a bit tedious.. I found toDelegate:
>> http://dlang.org/phobos/std_functional.html#toDelegate
>
> Or make it a template parameter and check if it's callable using
> std.traits.isCallable.
>
What's wrong with toDelegate ? Seems to be pretty handy.

//simple snip
import std.functional;

int main()
{
     int delegate( int i) dg;
     alias dg callback;
     callback = toDelegate(&test);
     writeln( callback( 12 ) );
     readln();

     return 0;
}

int test(int i) { return 30 +i;}