Re: src/dictionary.c

[Ben Pfaff]

John Darrington <address@hidden> writes:

> For a while, I've been unhappy about the way the GUI makes use of
> dictionary.c
>
> Currently, we have an object called PsppireDict which contains a
> pointer to a (struct dictionary) which is created externally.  In
> order that PsppireDict is aware of changes made to to (struct
> dictionary), the latter has a set of callbacks to which the containing
> PsppireDict connects.  Further, the (struct dictionary) can be
> destroyed, whilst the PsppireDict survives.  Typically, this happens
> on each procedure - the old dictionary is destroyed and a new one
> created in its stead.  The gui has to anticipate this, and reload the
> new dict, and it emits a "backend-changed" signal.  All of this is
> really messy, and is beginning to make the GUI unmaintainable.

The one thing that would worry me about making dictionary a
"virtual class" is that it would, I think, be a very broad class.
That is, it would have quite a large number of member functions.
The cleanest and most beneficial virtual classes, in my
experience, are those that encapsulate complex behavior behind a
very simple interface.  I think that the casereaders are a good
example, actually.

If you want to take a stab at re-implementation in this form,
though, then I'd be happy to take a look at the result.  I've
been surprised before when you have shown that changes that I
thought would be difficult or awful were really not so bad.
-- 
Ben Pfaff 
http://benpfaff.org