I started a Tk calculator script a day or two ago and I nearly have it. I've already posted here but I feel that this problem could be better addressed on its own.
I am getting this error from the script
Uncaught exception from user code:
Can't call method "Button" on an undefined value at C:\Documents and S
+ettings\Eoin\Desktop\calc.pl line 52.

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From what I understand from the error is that it is saying that  $rows[$r] is undefined. Where as @rows is quite clearly defined, as is $r.

UPDATE: I've discovered that the error is being caused by having the function button chars (i.e. * n* - \ + =) in the array for $i
for my $i (
qw/
   7 8 9 * n*
   4 5 6 - \
   1 2 3 + =
   0 . C     / )

[download]
Now i'm really confused!!

Heres the rest of it. 
my $mw = new MainWindow(-title => 'Calc');
$mw->geometry("300x300");
my $topframe = $mw->Frame(-height => '60', -width => '300')->pack(-sid
+e => 'top', -expand => '0', -fill => 'x'
+);
my $btmframe = $mw->Frame(-height => '225', -width => '300',)->pack(-s
+ide => 'left', -expand => '1', -fill => 
+'both');
push @rows, $btmframe->Frame()->pack( -expand => 1, -fill => 'both', -
+side => 'top') for (0..3);

my $display   =  $topframe->Entry(-justify      => 'right',
                                  -state        => 'disabled', 
                                  -textvariable => \$calc)
                           ->pack(-expand       => '1',
                                  -fill         => 'x',
                                  -pady         => 30,
                                  -padx         => 20,
                                  -side         => 'right');

$mw->bind("<KeyRelease>" , sub { &keypress } );
my $r = 0;

for my $i (
qw/
   7 8 9 * n*
   4 5 6 - \
   1 2 3 + =
   0 . C     / )
{

if($i eq '+' || $i eq '=')
{
$h = 2;
}
########LINE 52 BELOW################
$button{$i} = $rows[$r]->Button(-text    => "$i", 
                                -width   => '3', 
                                -height  => "$h", 
                                -command => sub { &btnpress($i) })
                         ->pack(-expand  => 1,
                                -fill    => 'both',
                                -padx    => 2, 
                                -pady    => 2,
                                -side    => 'left',
                                -ipadx   => 5, 
                                -ipady   => 5);

$w++;
$h = 1;
if($w > 2){$w = 0; $r++;}
}

MainLoop;

[download]
If anyone has any ideas on whats causing the problem, feel free to let me know. All and any help is greatly appriciated. :)

Cheers, Eoin...

In reply to Undefined Button method?? by eoin

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