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Fri Apr 6 11:13:23 EDT 2001 · http://mail.python.org/pipermail/python-list/2001-April/088779.html

"Brian Elmegaard" <be at mek.dtu.dk> wrote in message
news:3ACDBA00.BB1B10D1 at mek.dtu.dk...
    [about not _needing_ lambda]
> But (how) can the same be done with tkinter callbacks?

Just the same way: you can re-write the lambda, for clarity,
as a named local function, and pass that object.

> Take the apply example of mine. How would that look with def's?
>
> button.configure(command = lambda self=self,
>                  button=button, buttons=self.buttons,
>                  setting=CurrentCanvasSetting:
>                  self.apply(button,buttons,setting))

Which would become, to be literal in the transliteration:

    def configure_command(self=self, button=button,
            buttons=self.buttons, setting=CurrentCanvasSetting):
        self.apply(button, buttons, setting)

    button.configure(command = configure_command)

> In apply I (now) do:
>          def apply(self,button,buttons,setting):
>              setting[0]= button.cget('text')

That is another issue from 'avoiding lambda in favour of
named local functions' (which is strictly about clarity:
a local function may be clearer than a lambda, or,
according to personal taste, vice-versa).

Here, if I understand correctly, what you're trying to do
is somehow set an appropriate "global" string when a
function is executed.  If that CurrentCanvasSetting is
a variable name in some module, and the module-object
is known to you as (e.g.) modobj, you could pass those
to your 'apply' function in some form or other:

    def configure_command(self=self, button=button,
            modobj=modobj, varname='CurrentCanvasSetting'):
        self.apply(button, modobj, varname)

    button.configure(command = configure_command)

and in the apply method:

    def apply(self, button, modobj, varname):
        setattr(modobj, varname, button.cget('text'))

> This long explanation really clarified things for me. The thing is that
> I have grown up with boxing languages, so post-it's, I now have to

Me too -- Fortran, Pascal, various machine-languages, lo that
many years ago.  But I remember when the light first dawned on
me, about what was REALLY going on in my very first "post-it
language" (a LISP dialect), how it felt as if mists were
dissipating...!-)

Alex

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Changing global variables in tkinter/pmw callback