Thread overview
howto make a function get a types form compilte-time-parameters AND from the arguments ?
Oct 31, 2013
Uplink_Coder
Re: howto make a function get types form compile-time-parameters AND from arguments ?
Oct 31, 2013
Uplink_Coder
Oct 31, 2013
John Colvin
Oct 31, 2013
Uplink_Coder
October 31, 2013
(this is my first post so please alert me to any breaches of forum etiquette)

Hello,
I have a problem with a helper function I'm writeting.

T[] makeArray(T,U)(immutable U[] paramArray) {
 	T[] result;
 	foreach (param;paramArray) {
		result ~= T(param);
 	}
 	return result;
}

and I would like not to take the compile-time-parameter U but insead infering it form the argumet.

is it possible ?
and if. how ?

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Uplink_Coder
October 31, 2013
Maybe I shuold be more specific :
for now It's:
T[] arr = makeArray!(T,U)([some,instances,of,U]);

but I would like it to be:

auto arr = makeArray!(T)([some,instances,of,U]);




October 31, 2013
On Thursday, 31 October 2013 at 10:18:25 UTC, Uplink_Coder wrote:
>
> Maybe I shuold be more specific :
> for now It's:
> T[] arr = makeArray!(T,U)([some,instances,of,U]);
>
> but I would like it to be:
>
> auto arr = makeArray!(T)([some,instances,of,U]);

void foo(T,U)(U arg){}

int a;
foo!(double)(a); //U is inferred as int


void bar(T,U)(U[] arg){}

long[] b;
foo!(double)(b); //U is in inferred as long


However, be aware that you can't pass mutable or const data as an immutable argument. Perhaps the signature that would work better for you would be

T[] makeArray(T,U)(const U[] paramArray)
October 31, 2013
by changeing
T[] makeArray(T,U)(immutable U[] paramArray)
into
T[] makeArray(T,U)(const U paramArray) if (isAggregateType!(U) || is Array!(U))
everything works perfectly

Thanks very much

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Uplink_Coder