[Request] A way to extract all instance of X from a range

[Stefan Koch via Digitalmars-d]

On Monday, 14 March 2016 at 23:34:37 UTC, Stefan Koch wrote:
> On Monday, 14 March 2016 at 08:04:18 UTC, deadalnix wrote:
>> Right now, I'm repeating the following pattern many times :
>>
>> range.map!(x => cast(Foo) x).filter!(x => x !is null)
>>
>> Which is kind of annoying. Could we get something in phobos to 
>> do this ?
>
> There you go ;)
>
> alias castRange(T) =  map!(x => cast(T) x).filter!(x => x !is 
> null);

Ooops ;) didn't work
then it'll has to be done with a wrapper struct ...