> On Nov 28, 2018, at 7:26 PM, Sven Barth via fpc-pascal
> <fpc-pascal@lists.freepascal.org> wrote:
>
> Because that is not supposed to work. Generic routines are *routines*, not
> types. You can't define aliases for routines either, not to mention the
> problems with scoping as generic methods exist as well.
It seems natural you could specialize a generic procedure because you can do
this for all other generic types. Maybe a type isn’t the right way but it feels
like there should be some way to specialize the procedure header outside of a
begin/end block. I know you can't make aliases to procedures but generics are
more of “instantiating a template” which falls outside the scope the language
in general.
>
> Generic routines however have a different boon in Delphi that I plan to add
> as well: inference of the type parameters based on the parameters the user
> passed. In that case the type parameter clause as well as the "specialize" in
> non-Delphi modes would not need to be used and it would look like a normal,
> non-generic call.
That’s probably the best way (Swift does this and I always wondered why FPC
doesn’t) but it won’t work unless the parameters contain the generic parameter,
which is a minority of generics functions anyways.
Just to be sure, you mean like this?
generic procedure DoThis<T>(msg:T);
begin
end;
begin
DoThis(‘hello’); // compiles as “specialize DoThis<string>(‘hello’)”
because param types match generic parameter types
If all that’s involved is comparing params types to generic types then that
looks like a relatively simple solution. Const generic params may have
complicated this some however.
Regards,
Ryan Joseph
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