template alias = parameter

[Dicebot]

On Tuesday, 17 September 2013 at 11:24:10 UTC, Luís Marques wrote:
> Could you please comment on the following behaviors? Are all of 
> them intended? Are they internally coherent, with respect to 
> each
>  other?

Looks fine to me.

> 1)
>     void foo(alias f)(int f)
>     {
>         writeln(f);
>     }
>
>     foo(42);
>
>     Error: does not match template

`alias` is never inferred so error is expected. You did not 
provide any template parameters to foo. `void foo(T)(T f)` would 
have worked because `T` can be inferred.

> 2)
>     ...
>     foo!(42)(42);
>
>     > 42

Explicit template parameter + normal parameter. Name of normal 
parameter shadows alias name (would have expected a warning/error 
here tbh).

> 3)
>     ...
>     foo!(7)(42);
>
>     > 42

Same as (2).

> 4)
>     void foo(alias f)(int g=f)
>     {
>         writeln(g);
>     }
>
>     foo(42);
>
>     Error: does not match template

Again, you do not provide template parameter, it can't match. 
`foo!(42)()` should have worked here.

> 5)
>     void foo(alias f=42)(int g=f)
>     {
>         writeln(g);
>     }
>
>     foo();
>
>     > 42

Default parameters can be used everywhere so no need to provide 
any parameter explicitly.