[fpc-devel] Templates / Generics Syntax

[Marc Weustink]

Daniël Mantione wrote:
> 
> Op Thu, 3 Nov 2005, schreef Mattias Gaertner:
> 
> 
>>Here is a proposal of the syntax:
>>
>>type
>>  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)

BTW,
what woud be the problem with

type
   TMySpecificClass = TGenericClass(TObject, Integer);

var
   MSC: TMySpecificClass;

begin
   MSC := TMySpecificClass.Create




Marc