[fpc-devel] "Default" discussion for SmartPointers etc

[Jonas Maebe]

Maciej Izak wrote on Wed, 27 Jul 2016:

> @@ operator is very simple way to determine where you point. In any other
> case we have casting hell. See below (and more below). @@ exist rather as
> fulfillment to pa := @a; form tdefault7.pp (anyway is necessary for untyped
> pointers). You might not like @@ operator but @@ is part of long tradition.
> In practice works like a charm and is very clear.

Getting rid of the @@-operator is also part of a long tradition in  
FPC. In fact, it was one of the first differences between FPC and  
Turbo Pascal modes, and it is the reason why we use a different  
procvar syntax (because we considered it very unclear). There is no  
@@-operator in FPC/ObjFPC modes at this time.

On a more general note, I think the fact that @recordvar no longer is  
a pointer to the record is wrong. You need a different keyword instead  
of "record" in that case (or possibly a modifier for the "record"  
keyword, like with "class abstract" -- but this is not a record at any  
more than an shortstring is a record, so I don't think that's a good  
idea either).

Completely changing how certain aspects of a record are treated by the  
compiler only based on the fact that somewhere there is a "default"  
modifier for one field is not good. You should definitely not have to  
go through an entire declaration of a record to be able to know how it  
will behave.


Jonas