November 07, 2015 Cannot use local 'i' as parameter to non-global template | ||||
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template IsSame(T){ template As(alias t){ enum As = is(T : typeof(t)); } } void main() { int i; enum b = IsSame!int.As!(i); } Err: Error: template instance As!(i) cannot use local 'i' as parameter to non-global template As(alias t) dmd failed with exit code 1 I don't understand the error message. I also tried template IsSame(T){ enum As(alias t) = is(T : typeof(t)); } Which results in Error: template app.IsSame!int.As cannot deduce function from argument types !()(int), candidates are: source/app.d(50,8): app.IsSame!int.As(alias t) What am I doing wrong? Ps: Also posted on SO https://stackoverflow.com/questions/33584130/cannot-use-local-i-as-parameter-to-non-global-template not sure where people usually ask questions about D. |
November 08, 2015 Re: Cannot use local 'i' as parameter to non-global template | ||||
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Posted in reply to maik klein | On Saturday, 7 November 2015 at 15:04:41 UTC, maik klein wrote:
> template IsSame(T){
> template As(alias t){
> enum As = is(T : typeof(t));
> }
> }
> void main()
> {
> int i;
> enum b = IsSame!int.As!(i);
> }
>
> Err:
>
> Error: template instance As!(i) cannot use local 'i' as parameter to non-global template As(alias t) dmd failed with exit code 1
> I don't understand the error message.
>
> I also tried
>
> template IsSame(T){
> enum As(alias t) = is(T : typeof(t));
> }
>
> Which results in
>
> Error: template app.IsSame!int.As cannot deduce function from argument types !()(int), candidates are: source/app.d(50,8):
> app.IsSame!int.As(alias t)
>
> What am I doing wrong?
>
> Ps: Also posted on SO https://stackoverflow.com/questions/33584130/cannot-use-local-i-as-parameter-to-non-global-template not sure where people usually ask questions about D.
Two ways to go about doing this
template IsSame(T,U)
{
enum IsSame = is(T : U)
}
or make i a "global" by using a template
alias Identity(T) = T;
template IsSame(T){
enum As(alias t) = is(T : typeof(t));
}
enum b = IsSame!int.As!Identity!(i);
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