RE: Gtk tabs in emacs, new branch.

[Stephen J. Turnbull]

Drew Adams writes:

 > I want a tab to be able to invoke any function whatever.

While perhaps sufficient generality may require that ability, remember
that tabs as a metaphor are *not* just a contiguous row of buttons.
They are ordered, and they "do the same thing" (but to different
objects).  (There is an analogy to the difference between "a set of
check boxes" and "an array of radio buttons", where the radio buttons
aren't constrained to do the same thing, but rather to be mutually
exclusive.)

So I would refine "any function whatever" so that each tab control
should have a *single* callback function, which takes maybe three
arguments: the individual tab object itself (perhaps represented as an
integer but better a symbol, I think, because then you could put
properties on it), a per-tab user-defined datum (any Lisp object the
application wants to hang on the individual tab), and perhaps another
user-defined datum for the whole tab control.  (If you do need the
generality of function-per-tab, you could always have the tab-control-
wide function dispatch to per-tab functions stored in the per-tab user
datum.  This would *remind* you that all tabs in a group "should" do
the same thing, but it wouldn't *enforce* it.)

Either the per-tab datum or the whole-tab datum or both could be
subsumed by properties on the tab object, I guess.

WDYT?