Re: Making gdk-event-area work

[Marius Vollmer <mvo at zagadka dot ping dot de>]

Mark Seaborn <mseaborn@argonet.co.uk> writes:

> Pairs are usually used to represent lists, and a lot of static type
> systems only let you store lists in the cdr of a pair.

If that a static type system is intended to be used with Scheme, then
it is fundamentally broken.  Pairs are used in a non-list manner all
the time, for association lists, for binary trees, etc.

> It's true there are times when improper lists are useful, but I
> don't like being gratuitously incompatible with other type systems.
> I might want my Scheme code to interoperate with them later.

I think this fear is unfounded.  There is no way that such a type
system could be used extensively with Scheme.
 
> It's also not very readable using `car', `cdr', etc. for this.  I
> suggest providing some accessor functions, `bbox-min-x',
> `bbox-min-y', etc., and saying the representation might change in a
> later version.

Yes, that's a good point.  We might want to change to using Goops, for
example, and have proper types for 2D-points and stuff.  What about
names like

    gdk-point-x            car
    gdk-point-y            cdr

    gdk-rect-pos           car
    gdk-rect-size          cdr
    gdk-rect-x             caar
    gdk-rect-y             cdar
    gdk-rect-w             cadr
    gdk-rect-h             cddr