On Thu, 20 Aug 2015, Torsten Bonde Christiansen wrote:
On 2015-08-20 08:06, Sven Barth wrote:
Am 20.08.2015 03:42 schrieb "Fabio Luis Girardi" <fluisgira...@gmail.com
<mailto:fluisgira...@gmail.com>>:
> Currently, I'm doing a small program that uses libraries, objects and the
operator IS, that is know that this operator fails because of duplication
of VMT.
And /that/ is one of the reasons why dynamic packages were invented...
>
> Everyone know some alternative (or more elegant) method to test if a
object created on a library is a class descendant without use
object.ClassName? Or in case of use String to check the class name, how
retrieve the class name of all descendant classes from a object?
>
Nope, there is no more elegant way. And you'll probably need to walk the
class tree using ParentClass and retrieve each name.
Note: an except-handler will suffer from the same problem if it needs to
catch an exception that was raised from the library (or the other way
round).
You are going to a extreme fragile direction there.
What about TObject.InheritsFrom(aclass : tclass) - Is that not the equivalent
of the *IS* operator
It is, but will suffer from the same problem.
The library has a completely separate VMT and inheritance tree from the calling
program.
You need dynamically loadable packages for this to work.
Michael.
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