Default radio button in Tk

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

Fellow monks,

I'm having a bit of a problem finding any docs on this. I want to set the default on a radio button. This is my code thusfar:

$shape="square";

(stuff deleted)

foreach ('square  ', 'circle ', 'polygon'){
         $frame2->Radiobutton(
                              -bg=>COLOR,
                              -activebackground=>COLOR,
                              -text=>$_,
                              -font=>'code14',
                              -value=>$_,
                              -variable=>\$shape,
                              )->pack(-anchor=>'w');
         }
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My question is: Why isn't the radio button being set to square initiallly since I've set the variable? The radio buttons are being drawn fine, but with none selected.

All I can find in Mastering Perl/Tk is a reference to the default on a regular button. There is nothing listed in the reference charts in the back either. Have I missed something here?

Thanks!

Comment on Default radio button in Tk Download Code

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Re: Default radio button in Tk by ariels (Curate) on May 05, 2002 at 06:06 UTC
You'll kick yourself. The value of `$shape` for setting a square is `'square '`, not `'square'`. Update: Of course, the spaces in your list of names serve no purpose. You cannot (in general) use spaces to align text, because not all fonts are fixed-width. And since you're telling `pack` to `anchor => 'w'`, you'll get the desired(?) left-justification anyway. Just say "`foreach ('square','circle','polygon')`" and have done with it...	[reply] [d/l] [select]

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Re: Default radio button in Tk
by ariels (Curate) on May 05, 2002 at 06:06 UTC

You'll kick yourself.

The value of $shape for setting a square is 'square ', not 'square'.

Update:

Of course, the spaces in your list of names serve no purpose. You cannot (in general) use spaces to align text, because not all fonts are fixed-width. And since you're telling pack to anchor => 'w', you'll get the desired(?) left-justification anyway.

Just say "foreach ('square','circle','polygon')" and have done with it...

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