OOP_(re)

Tue, 27 May 1997 10:24:16 +0100 (BST)

On Mon, 26 May 1997 20:09:51 -0400 (EDT) Pierre Phaneuf  wrote:
>On Mon, 26 May 1997, Frank Heckenbach wrote:
>
>> Bottom line: I don't think it can be done all automatically, but it can be
>> done much more comfortably to the programmer than in TV.
>
>I agree with you. I am in effect creating a better way to do it, but it
>will NOT be in BPCOMPAT. I'm a proficient user of TV, and I'll try to have
>the object parts of the BPCOMPAT package as compatible with it as
>possible... It *will* be in a GPC-specific class library of mine I'll
>contribute to the GPC team "When It's Ready (TM)", of course! ;-)

It would be nice if your classlib could build on the object heirarchy
in BPCOMPAT, instead of introducing a completely new one (at least,
if all your main "PierreObject" is a descendant of TObject). This 
would ensure some continuity. You could amend TObject if necessary,
so that it would meet your needs as the ultimate ancestor of your
own objects. All that is necessary is to ensure that programs written to 
use TObject as it currently is (which would be very few indeed) are not
broken, which will be a trivial thing to do.

Also, when implementing your new TV stuff, it would be nice to make it
more friendly. I find Borland's TV quite incomprehensible - it is as if it
wasn't made by the same company that made OWL (which I find to be
easier to deal with). But perhaps it is because I lost patience with TV
very quickly.

[...]
>> > We are in part.  The primary goal of GPC is to produce the best Pascal
>> > compiler the world has ever seen.
>> 
>> I agree with Peter. I, FWIW, didn't use TV -- partly because some parts
>> of it (including class registration) were, IMHO, badly implemented.
>> If gpc's TV would be the same, I probably wouldn't use it, either.
>
>Yes, I agree, but let's keep in mind what we're looking to fix in this
>thread is the BPCOMPAT package, which will have to look like BP libraries
>are, at least on the outside. 

I think that this is crux of the matter. We are trying to produce a package
that will allow GPC to compile BP programs (i.e., the external interface is 
similar to that of BP). We  are not concerned to ensure that the internal 
implementation is identical to that of BP (unwanted side effects aside). 
We are also not concerned to ensure that the code will compile under BP 
itself. Much of the current BPCOMPAT will not compile under BP, because 
of the use of functions from the C library, and the use of EP initialization 
and finalization stuff. So, please let us not hamstring ourselves by trying 
only to write code that will also compile under BP. Eventually, BP will go
the way of the dodo - GPC is the way forward! 

> BTW, what didn't you like exactly with TV?

Personally, it seemed too tedious to write any useful code. Felt like
it was a classlib written by a sadist or a masochist, or both ;-). 
However, some people feel that way about OWL too - and I personally
prefer OWL to TV or even to Delphi's VCL.

>As for the class registration, what I didn't like was that it used the
>data segment, which isn't a very clean hack IMHO... Apart from that, it's
>ok by me (the class registration system!). The Free method is one of the
>purest evils in there. :-) (and it is in the BPCOMPAT package!)

Well, Free() was included just because Borland included it (i.e., "external"
compatibility).

>> So we may need both: a "100% BP compatible" unit for quick changes, and
>> a "better" gpc unit to which programs can be converted afterwards, and
>> which new programs can use from the beginning. Actually, I think, the
>> changes needed for BP programs shouldn't be too big: make the "Load"
>> constructor virtual (if we do it this way), declare the "ObjID" constant,
>> and remove the registration stuff. Could even be simplified with some
>> "IFDEF"s and clever use of the preprocessor, I guess.
>
>I'm developing something here for a "GPC enhanced" class library, I'll
>keep you posted! 

That would be great. Which objects are you thinking of including? Are
you tailoring it after [a] TV (eek!!); [b] OWL (:-)); [b] VCL ( !!); [d] OPRO (;-/);
[e] something else ?

>"The use of COBOL cripples the mind; its teaching should, therefore, be
>regarded as a criminal offense." - Edsger W. Dijkstra.

Except it can save the world from the Year 2000 fiasco!

Best regards, The Chief 
Dr Abimbola A. Olowofoyeku (The African Chief, and the Great Elephant)
Author of:  Chief's Installer Pro v3.50 for Win16 and Win32.
Homepage:  http://ourworld.compuserve.com/homepages/African_Chief/
E-mail: laa12@cc.keele.ac.uk


The African Chief (laa12@cc.keele.ac.uk)