[fpc-devel] Templates / Generics Syntax
nc-gaertnma at netcologne.de
Fri Nov 4 13:38:06 CET 2005
On Fri, 04 Nov 2005 10:47:42 +0100
Marc Weustink <marc.weustink at cuperus.nl> wrote:
> Daniël Mantione wrote:
> > Op Thu, 3 Nov 2005, schreef Mattias Gaertner:
> >>Here is a proposal of the syntax:
> >> TGenericClass<T,F> = class
> >> public
> >> procedure Add(Item: T; Flag: F);
> >> end;
> > This syntax is almost impossible to implement since in one of your other
> > mails the symbols to mark the parameters appear in regular source code:
> > begin
> > generictypeA<integer>.create
> > end.
> > It will be very hard for the parser to see the difference in advance
> > between:
> > variable<integer(another_var)
> > generic_type<integer
> > Only when the > symbol is parsed the result is known.
> > Maybe the parser may be able lookup the type first and make a decision
> > based on that, but it would be in the middle of a recursive expression
> > parse designed for infix operators.
> > Also in C++ this sometimes causes trouble where you need to change your
> > code notation so the compiler eats it. I don't know if this proposal
> > suffers from this mess, but we should avoid at all cost to import it
> > into Pascal.
> On the wiki pages some of my remarks got lost (or I didn't write them
> down) but when I first looked at the <> notation style it looks very
> unpascalish for me. I like more to add a new keyword for it, like the
> samples wiht generic or template)
> what woud be the problem with
> TMySpecificClass = TGenericClass(TObject, Integer);
What about proc generics:
This can be ambigious.
> MSC: TMySpecificClass;
> MSC := TMySpecificClass.Create
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