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From: andrew@resam.dk (Leif Andrew Rump)
Newsgroups: comp.object,comp.lang.pascal
Subject: Re: Shouldn't debuggers be able to debug dynamic objects?
Message-ID: <1991Jan28.100213.1822@resam.dk>
Date: 28 Jan 91 10:02:13 GMT
References: <1991Jan24.152256.24273@resam.dk> <1991Jan25.145947.16431@bellcore.bellcore.com>
Distribution: comp
Organization: RESAM Project Office, SAS, CPHML-V
Lines: 43

In <1991Jan25.145947.16431@bellcore.bellcore.com> bytor@ctt.bellcore.com (Ross Huitt) writes:

>In article <1991Jan24.152256.24273@resam.dk> andrew@resam.dk (Leif Andrew Rump) writes:
>>I experienced a rather annoying feature in TurboPascal 5.5 (but I
>>think the problem may exist in a lot of other (integrated) debuggers
>>used to debug object oriented programmes.
>>The program enclosed create two (2) dynamic objects: a square & a
>>box.
>>The first thing to notice is that the compiler only allow squareptr
>>to be used as a general object for squares & boxes! Well I could
>>accept that _IF_ the debugger (integrated & external (TD)) at least
>>would notice when I create a box! But no - it only display the
>>content of a square - the length has to be extracted manually!!!
>>
>...code deleted
>>

>When I _know_ which derived class a base class ptr is pointing to
>and I want to inspect or display the object as a derived class, a cast
>is usually sufficient to get the job done.  With the Turbo products,
>simply type in 'squareptr(general_object(1))' at the Display or 
>Evaluate prompts.  I don't know for sure that the technique works with
>Turbo Pascal or if this particular syntax is correct, but I do use the
>technique with C++ frequently.

But, but, but, ... Why can't the debugger that has _all_ the information
do this job! The main reason for me to write this letter was that one
of my programmes used a dynamic list of objects and if I was going to
use the debugger to show me the content of for example the first three
objects in a list a had to remember what type each object was and change
casts accordingly - then (as I wrote in my original letter) I surely
sill make mistakes and then the debugger only caused havoc!!!

Leif Andrew


Leif Andrew Rump, AmbraSoft A/S, Stroedamvej 50, DK-2100 Copenhagen OE, Denmark
UUCP: andrew@ambra.dk, phone: +45 39 27 11 77                /
Currently at Scandinavian Airline Systems                =======/
UUCP: andrew@resam.dk, phone: +45 32 32 51 54                \
SAS, RESAM Project Office, CPHML-V, P.O.BOX 150, DK-2770 Kastrup, Denmark

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