Re: [tcltk-perl] Why is Tcl a subclass of Tck::Tk?

[Gisle A. <gi...@Ac...>]

"Konovalov, Vadim" <vko...@sp...> writes:

> > In Tcl.pm I see this code:
> > 
> >     unless (defined $Tcl::Tk::VERSION) {
> >         package Tcl::Tk; # define empty package
> >     }
> >     use vars qw(@ISA);
> >     @ISA = qw(DynaLoader Tcl::Tk);
> 
> I can agree this is not very correct way to do things...
> 
> > 
> > Why is Tcl as subclass of Tck::Tk insted of the other way around?  The
> > other way seems more logical.
> 
> Could you please explain your way of doing things?

I would expect:

   $tcl = Tcl->new;

to give me an interpreter that only can do the plain Tcl stuff,
i.e. what tclsh can do.

I would expect:

   $tcltk = Tcl::Tk->new

to be a subclass of Tcl that can do plain Tcl stuff as well as all the
Tk stuff, ie. what wish can do.

I don't expect my $tcl to suddenly grow more capable or different just
becase I happened to load the Tcl::Tk module in the same process
later.  Perhaps I just misunderstand what tcl actually looks like
underneath.  I have not used actually tcl in 15 years, so my memory of
what it is is rusty.

> The point here is that Tcl::Tk interpreter actually *is* plain Tcl
> interpreter and may be they be'll better joined intoone single module.

I think the separation is ok.

> OTOH having two different modules -- one is for low level communicating, and
> other is for Tk part (GUI and perlTk compatibility) is very handy for me:
> developing of Tcl::Tk could be done more easily and independent.

Agree.

--Gisle