meraxes has asked for the wisdom of the Perl Monks concerning the following question:

I humbly submit another question to the monks.

I'm in the middle of learning perltk and I must admit to some confusion. I was attempting to create another window in this simple example using the TopLevel method. Alas, it does not work. I'm running this on a Win2k machine using ActiveState Perl v.5.6.1 build 626. The Perltk module was installed using their ppm utility.

Here's my code:

#!/usr/bin/perl -w

use strict;
use Tk;
require Tk::TopLevel;

sub newWindow();
sub closeWindow();

my $TestWindow;

my $main = MainWindow->new();

$main->Button( -text    => "Click Me",
               -command => \&newWindow)->pack();


MainLoop;

sub newWindow () {

   $TestWindow = $main->TopLevel();
   $TestWindow->Label ( -text    => "I want to make a new toplevel win
+dow!")->pack();
   $TestWindow->Button( -text    => "Close Me",
                        -command => \&closeWindow)->pack();

}

sub closeWindow() {
   $TestWindow->destroy();
}

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Now, the ruddy thing compiles just fine. However at runtime it produces the following errors (which make precious little sense to me):

Subroutine Tk_cmd redefined at D:/Perl/site/lib/Tk/TopLevel.pm line 14
+.
Subroutine CreateOptions redefined at D:/Perl/site/lib/Tk/TopLevel.pm 
+line 17.
Subroutine Populate redefined at D:/Perl/site/lib/Tk/TopLevel.pm line 
+22.
Subroutine Icon redefined at D:/Perl/site/lib/Tk/TopLevel.pm line 29.
Subroutine menu redefined at D:/Perl/site/lib/Tk/TopLevel.pm line 64.
Subroutine Toplevel redefined at D:/Perl/site/lib/Tk/Widget.pm line 24
+7.
Assuming 'require Tk::TopLevel;' at D:\Work\test2.pl line 22
Tk::Error: Failed to AUTOLOAD 'Tk::Widget::TopLevel' at D:\Work\test2.
+pl line 22
 Carp::croak at D:/Perl/lib/Carp.pm line 119
 Tk::Widget::__ANON__ at D:/Perl/site/lib/Tk/Widget.pm line 338
 main::newWindow at D:\Work\test2.pl line 22
 [\&main::newWindow]
 Tk callback for .button
 Tk::__ANON__ at D:/Perl/site/lib/Tk.pm line 228
 Tk::Button::butUp at D:/Perl/site/lib/Tk/Button.pm line 111
 (command bound to event)

[download]

Where is my problem here? The Code? The installation of the module? I must admit, that I find the online information on PerlTk to be sparse (Found the FAQ, found the docs at CPAN) and more than a little confusing for me. I learn best by seeing examples. Any help/explanation would be greatly appreciated.

|\/|eraxes

Replies are listed 'Best First'.
Re: Perltk and TopLevel
by ariels (Curate) on May 21, 2002 at 15:08 UTC

    s/TopLevel/Toplevel/mg;

    "require Tk::TopLevel;" doesn't bomb out because you'd appear to be on a Windows system (file search is case-insensitive). But Tk::TopLevel isn't being found, because it's Tk::Toplevel...

    Oh, and it's probably a better idea to "use Tk::Toplevel;".

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[d/l]
[select]

      I've tried changing the "require" line as you specified but now I get an extra line in the error codes:

      Assuming 'require Tk::TopLevel;' at D:\Work\test2.pl line 21

      And still no window. :(

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[d/l]
        You need to also change the line where you create the new top-level window.

        $TestWindow = $main->Toplevel();

        It's not just the require that needs to change... The /m on ariels' substitution indicated that you needed to change TopLevel->Toplevel everywhere...

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[d/l]
[select]
      Damn I hate MixedCaseVariableNames. Because I can't remember them as sounds. Is it topLevel or Toplevel or TopLevel? If I wrote the code, it's "top_level". Period. And what if there's an acronym buried in the variable name? Is it CvsVersion or CVSversion? Or - god help us - CVSVersion? When the revolution comes, the inventors of mixed case variable names will be the first against the wall!
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