That’s a good question, I guess most of us end up with huge files?! (I know I do)

Other monks asked the same question before: How to structure LARGE Perl/Tk application? or Is there a MVC framework for perl/tk?

It looks like somebody attempted something like you want, take a look at Tk: Verallgemeinertes MVC-Schema. It’s in German though and last update 2000...

Update
Didn't realize you're from Germany. I guess the language won't be a problem:-)

Thank You, that was something I was too stupid to find with Super Search, but that gives me a lot hints.

And it came to pass that in time the Great God Om spake unto Brutha, the Chosen One: "Psst!"
(Terry Pratchett, Small Gods)

Draw your layout; and have a naming convention for widgets and variables that supports your nesting or management scheme. Then segment the callbacks (action code) into separate modules that are related... all input in one, all validations in another; or 1 module per GUI manipulation object/widget.

Trying to do incremental widget instantiation in a 'workproc' is probably beyond PerlTK.

Comment...Describe why...think maintainability.

If you havn't already, google for "perl Tk mega", "perl Tk derived", "perl Tk custom widgets", for how to modularize your Tk code snippets.

It depends. ;-)

I've used MVC in the past. But I've also split my applications by function: use a module that, say, deals with displaying an image. It'll both have the "business logic" and the interaction with the widgets to display it.

But most often, I use something in between. In the backend, there's code that deals with the "model", but the frontend code that deals with displaying and input also does input validation and some state transisitions.

I asked a similar question many moons ago: Name spaces and Perl::Tk coding style.

Later I asked for more advice as my app grew bigger: Perl Tk - propagating events.

I tend to wrap up the $main in a light weight object in the .pl file then pass that object into light weight object constructors in .pm files to manage dialogs and other such pieces that I want to organize into their own box. That lets me pass common information around in a blessed hash and allows maintenance of separate chunks of code in their own file.

I haven't time to provide a code outline at present, but ask and I'll whip up something tonight.

I do this way:

use strict;
use Tcl::Tk;
my $int = new Tcl::Tk;

$int->Eval (<<'EOS');
# here goes Tk code to construct GUI
pack [text .t]
pack [button .b -text button]
EOS

# and here goes main code with perl/Tk syntax
my $txt = $int->widget('.t','Text');

$txt->insert('end',"text text tex");
$int->MainLoop;
[download]

This has proven to be very convenient for all my Tk-GUI projects.
Indeed, separated GUI and logic,much easier to maintain than ordinary perl/Tk code.
Perl/Tk, in the contrary, is much more noisy than Tcl/Tk GUI.