On 16.07.2015 17:53, Marcos Douglas wrote:
On Thu, Jul 16, 2015 at 12:23 PM, Sven Barth
<pascaldra...@googlemail.com> wrote:
Am 16.07.2015 16:34 schrieb "Maciej Izak" <hnb.c...@gmail.com>:
sadly - no, only in Delphi mode. btw. this thing keep me away from objfpc.
Then let me tell you that generic methods will arrive in mode ObjFPC (and
thus its syntax) first, because the Delphi syntax is a PITA to parse/handle.
(in fact generic methods are already working in mode ObjFPC in my local
repo, I just want to get the Delphi ones working a little bit before
commiting to trunk)
I didn't understand. This already works... or you talking about "work
with the same syntax than Delphi in mode objfpc"?
Generic methods are not yet supported by FPC. Try the following Delphi
code in 3.1.1 for example (in mode Delphi):
=== code begin ===
type
TTest = class
function Add<T>(aLeft, aRight: T): T;
end;
function TTest.Add<T>(aLeft, aRight: T): T;
begin
Result := aLeft + aRight;
end;
var
t: TTest;
i: LongInt;
s: String;
begin
i := t.Add<LongInt>(2, 4);
s := t.Add<String>('Hello', 'World');
end.
=== code end ===
This does not compile in FPC currently. In my local repo the above is
close to working and the following non-Delphi-mode code definitely works:
=== code begin ===
type
TTest = class
generic function Add<T>(aLeft, aRight: T): T;
end;
generic function TTest.Add<T>(aLeft, aRight: T): T;
begin
Result := aLeft + aRight;
end;
var
t: TTest;
i: LongInt;
s: String;
begin
i := t.specialize Add<LongInt>(2, 4);
s := t.specialize Add<String>('Hello', 'World');
end.
=== code end ===
I will repeat also the last paragraph of the first message:
I would like to know why exists this difference, what the advantages
for mode objfpc using this syntax.
Less ambiguity for both the user as well as the compiler. In fact if I
had already been with a FPC developer back when generics were
implemented before 2.2 I had implemented specialization somewhat like
the following:
=== code begin ===
begin
i := t.specialize Add with (LongInt)(2,4);
i := t.specialize Add with (String)('Hello', 'World');
end.
=== code end ===
This way there would be no ambiguity with the "<" at all... but sadly I
wasn't a FPC developer back then. :) (and I would have needed to
implement the Delphi compatible one for mode Delphi anyway and just like
I do now I would have cursed just as much ^^)
Regards,
Sven
_______________________________________________
fpc-pascal maillist - fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
