BP style objects: errors._(re)

Sat, 26 Apr 1997 15:57:54 +0200 (MET DST)

According to Jan-Jaap van der Heijden:
> 
> 1) References to an incomplete type are not accepted. [...]

That's a new bug.  I will have a look at it.

> 2) Something simular appens in the implementation part:
>
> [...]
>
>   TErrorProc = procedure(var S: TStream);

GPC does not (yet;) have BP's "procedural variables".  It has *pointers*
to procedures instead.  The above can be translated to

    TErrorProc = ^Procedure ( ????????? TStream );

- ah, sorry!  `Var' parameters don't work in this context!  Bug!!!

Okay, I will see how difficult it is to implement BP's procedural types ...

> 3) Obviously, `self' is treated different too...

This I don't understand.

> All of this with the latest-but-one alpha release, in BP mode with
> extended syntax.

It should not be necessary to run GPC in BP mode.  `--borland-pascal'
does not switch ON anything; it only switches OFF the Extended Pascal
extensions.  And vice versa.  I suggest to write all new source for GPC's
default mode and to use `--borland-pascal' (or `--extended-pascal' for
that matter) just for testing or when worrying about compatibility to
Borland (respectively Extended) Pascal.

(*$X+, M Extended Syntax is a different thing because it really switches
ON some "dangerous" features of GPC. *)

> BTW: of course, what I was trying out, was how much trouble it would be to
> port TVision to GPC. Seems we have a long way to go....

We will see.  (* But anyway I aim to write something *better* ... ;*)

> With sufficient thrust, pigs fly just fine. However, this is not
> necessarily a good idea.  [...]

But there may be some people whose programs rely on flying pigs.  I am
prepared to implement yet another option `--flying-pigs' for such
purposes ...

Greetings,

    Peter

  Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer
peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201]
 maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

Peter Gerwinski (peter@agnes.dida.physik.uni-essen.de)