[GUI] State, Attributes and Some basic widgets

[Glynn Clements]

Alastair Reid wrote:

> There are other ways, of course, and we should explore them.  Perhaps
> you could make a concrete proposal Glynn?

The most obvious solution is to simply use a generic Widget type for
all widgets; this is the way that Xt behaves at the application layer.

The class hierarchy is only really relevant if you're writing new
widgets (and the CGA simply isn't going to be able to handle that
aspect in a reasonable way). The only sense in which the class
hierarchy is relevant at the application level is that a subclass will
have all of the attributes of its parent class.

In any case, it probably isn't practical to model the class hierarchy
in the CGA, as different toolkits have different hierarchies (e.g. 
Motif's push-button class is a subclass of label, but Qt's isn't). 
Although, it's likely that there is a common ancestor for "container"
classes.

-- 
Glynn Clements <glynn.clements@virgin.net>