Andrew Dunbar wrote:

> > I meant, that "part" ("piece", "chunk", whatever) of
> > software which handles cursor movements and editing
> > actions, [...]
>
> Well there is no such thing.

You wouldn't be able to type, if there wasn't such a thing, somewhere.

> Certainly no part of the OS. The keyboard map is part
> of the OS. Input methods are part of the OS. Rendering
> is part of the OS. And all of these are modular.

No centralized code for handling of arrow or delete keys? So every
programmer should reinvent the wheel at every other application?

> There is no central place which handles deleting etc.
> For widgest/gadgets/controls (whatever each OS calls
> them) there may be OS code which treats these events
> in a uniform way.

Which is exactly what you said did not exist...

> Outside these, in the main window
> of an editor or anything else which is not a standard
> control,

Can't the main window of an editor be a standard control? E.g., the main
window of Windows' Notepad is a standard text box. A simple editor of that
kind is only interested in intercepting applicative events such as menu
selections: it doesn't care what's going on in the text windows, as long as
it can rely on the fact that the text control will handle all the usual
stuff.

> there are only events which are passed to
> the application. Every application can do whatever it
> wants.

GUI applications do receive an event for every key press, but they normally
ignore it, so that the "system" (i.e., the text control, which is an DLL or
OCX belonging to the OS) already implements default text editing.

Most GUI applications are only interested in handling higher-level events,
such as the notification that an editing operation in a certain box has
completed, so that they can check the validity of the entered/edited data.

> > Of course, this "module" can just be a piece of an
> > applicative program (also the display module can:
> > not all applications use Uniscribe or similar
> > system-level facilities), but most typically it is a
> > service supplied by the system.
>
> Well there are very few Windows applications which
> don't use Uniscribe at all.

And very few Windows applications implement their special handling of arrows
or delete keys.

In any case, I was describing what each "logical module" does during an
editing session, because Susan was after the wrong impression that the
display module (Uniscribe, in Windows) handled things like the delete keys.
Discussing the precise software tier in which each one these modules sits in
*Windows* was quite out of the scope of my discussion, and quite OT for this
forum, I think.

--
Marco