Template argument types

[Alex Rønne Petersen]

On 12-06-2012 02:04, bearophile wrote:
> Do you know why D templates accept floating point values and even arrays
> of 32 bit dchars:
>
> template Foo(dchar[] s) {
> enum size_t Foo = s.length;
> }
> void main() {
> pragma(msg, Foo!("hello"d.dup));
> }
>
>
> But they don't accept arrays of ints?
>
>
> template Foo(int[] s) {
> enum size_t Foo = s.length;
> }
> void main() {
> enum int[] a = [1, 2, 3];
> pragma(msg, Foo!a);
> }
>
>
> ===>
> test.d(1): Error: arithmetic/string type expected for value-parameter,
> not int[]
>
>
> This works, but it's not the same thing:
>
> template Foo(alias s) if (is(typeof(s) == int[])) {
> enum size_t Foo = s.length;
> }
> void main() {
> enum int[] a = [1, 2, 3];
> pragma(msg, Foo!a);
> }
>
> Bye and thank you,
> bearophile

My guess is that dchar[] is special-cased in the compiler to allow 
passing strings. I think we should extend this to support arrays of all 
primitive types.

-- 
Alex Rønne Petersen
alex at lycus.org
http://lycus.org