Your question reveals an inside-out approach.

The ->Eval method is meant for exceptional stuff which can't be done with normal Perl methods.

The normal approach is to use standard pTk->methods to build menus and windows.

If your special wish is even possible I doubt that you'll get a quick answer here.

edit

Anyway ... if you just want to generate Tcl code from a Perl method inside your template you can do something like

->Eval(<<"__TCL__");

... some Tcl Code

@{[ my_perl_sub() ]}

... more Tcl Code

__TCL__
[download]

the result from my_perl_sub() is inserted as string then, which will be interpreted as Tcl code.