Greetings, O wise ones.

I am working on a Tk interface for my very first Useful Program[1]. The main window contains several frames which contain very similar widgets. I want to be able to pack/packForget the frames dynamically, so to improve readibility I would like each frame to have a descriptive name. I.e. not the frames should be elements of an array or something similar.

On the other hand, since the widgets inside each frame are so similar, I thought it would make sense to pack the widgets in a loop, packing one frame per cycle. I basically have a list of elements I wanted to iterate over, so a foreach loop seemed ideal. My first (and so far only) idea was to do something like this:

use strict;
use Tk;

my $mw = MainWindow->new;

my $hello_string = "Hello";
my $silly_string = "Very Silly!!!";


my $frame1 = $mw->Frame();    
my $frame2 = $mw->Frame();     
my $frame3 = $mw->Frame();
my $frame4 = $mw->Frame();   

my %frame_var_hash = 
          ($frame1 => {-text => $hello_string, width => 7}, 
           $frame2 => {-text => $silly_string, width => 9}, 
           $frame3 => {-text => "XXXXX",       width => 35},
           $frame4 => {-text => $silly_string, width => 7});

 
foreach my $cur_frame (keys %frame_var_hash){
    
    $cur_frame->Label(
              $frame_var_hash{$cur_frame},
              -expand => 1,
              )->pack();
}
[...]
MainLoop;

[download]

I thought this was fairly clever (I impress myself easily) but Perl disagreed:

Can't locate object method label via package
"Tk::Frme=HASH(0x286D960)" (perhaps you forgot to load
"Tk::Frme=HASH(0x286D960)"? at test line 27.

[download]

My reading of the camel book suggests that the loop variable takes on the identity of whatever list element is assigned to it. For example,

 foreach $element (@some_array){$element++}

actually increments the values in $some_array. Apparently this doesn't hold in a straightforward way for objects. I tried de-referencing $cur_frame, I tried using references to the frame objects as the keys in %frame_var_hash and then de-referencing $cur_frame, and I think I tried some other things but it was late and I forget.

Is there a way to make a loop like this work? Is there a better way to solve the problem? I am seated at you feet, listening.

-- Fuzzy Frog

[1] The guts have been working for almost two years. I just want to give it a pretty face. The person who will be taking over my job has never heard of a command line.

Edited by Chady -- escaped barackets and made them into a nice footnote link.

In reply to Iterating over objects by Anonymous Monk

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