Xref: utzoo comp.object:439 comp.lang.c++:5569
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!odi!dlw
From: dlw@odi.com (Dan Weinreb)
Newsgroups: comp.object,comp.lang.c++
Subject: Re: Has X Widget Library Collapsed?
Message-ID: <1989Nov20.040415.16653@odi.com>
Date: 20 Nov 89 04:04:15 GMT
References: <28.UUL1.3#913@acw.UUCP>
Reply-To: dlw@odi.com
Organization: Object Design, Inc.
Lines: 20
In-Reply-To: guthery@acw.UUCP's message of 17 Nov 89 03:29:27 GMT

Well, that story doesn't hold a lot of water.  For one thing, there is
no such thing as "the X widget library"; there are many separate X
widget libraries.  Some are undocumented, but others have very
extensive documentation (such as the Motif library).  So whoever told
you this story is pretty confused.

It's true that the code for the typical X widget (in any of the
libraries) is pretty hard to understand.  But inheritance is not the
cause of the problem.  The problem is that they are written in C,
which does not provide support for inheritance.  The poor
widget-writers have to do object-oriented programming without any help
from the language.  The resulting code is extremely verbose, and, in
my opinion, often obtuse.  If they used, say (just to pick a language
at random :-) C++, the code might be much cleaner.  For an example of
a user interface toolkit, based on X but not on the X intrinsics, and
written in C++, study InterViews.  It uses inheritance very heavily,
and inheritance makes its code much cleaner and easier to maintain
than if inheritance had not been used.

Dan Weinreb		Object Design, Inc.		dlw@odi.com