[fpc-pascal] Pass open array to static array?

[Sven Barth]

Ryan Joseph via fpc-pascal <fpc-pascal at lists.freepascal.org> schrieb am
So., 15. März 2020, 19:58:

>
>
> > On Mar 15, 2020, at 8:53 PM, Howard Page-Clark via fpc-pascal <
> fpc-pascal at lists.freepascal.org> wrote:
> >
> >
> > With recent FPCs you can however do this:
> >
> > program test;
> > var
> >   data: array[0..2] of Integer;
> >   tmp: array of Integer = Nil;
> > begin
> >   tmp := [1,2,3];
> >   Move(tmp[0], data[0], SizeOf(data));
> > end.
>
> yeah I figured you can do something similar with generics:
>
> generic procedure Move<T>(source: array of T; var dest);
> var
>   bytes: SizeInt;
> begin
>   bytes := length(source) * sizeof(T);
>   Move(source, dest, bytes);
> end;
>
> begin
>   specialize Move<GLfloat>([0.0, 0.5, 0.0,
>     -0.5, -0.5, 0.0,
>     0.5, -0.5, 0.0],
>     data.verts);
> end.
>
> but why doesn't open arrays already do this? an open array is just a
> constant array so the compiler should know the arrays are compatible for
> assignments.
>

The message of the compiler is a bit misleading. It's a *dynamic* array
that is created there, not an *open* array. Open arrays only exist when
being passed directly to a parameter.

But to answer why the compiler does not do it: because I simply have not
had the time to implement it! The main point of dynamic array constructors
was to have them Delphi compatible. Support for static arrays is something
I have planned though (and you're not the first to ask for it).

Regards,
Sven

>
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