in reply to Syntax error using Tk

You have a couple of errors, and don't forget to use warnings; and use strict;

First, you forgot a comma after 'ne' in your first pack.

Predeclare %button, and get rid of the my before $button{$i}. 

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = new MainWindow;
$mw->geometry("300x300");

my %button;
my $ans = 'foobar';

my $num_screen = $mw->Entry(-width => 40, -state => 'disabled',
                    -textvariable => "$ans")
            ->pack(-pady => 30, -anchor => 'ne', -side => 'top');

my @buttons = ( '9','8','7','6','5','4','3','2','1','0');

for (my $i = 9; $i >= 0; $i--)
{
$button{$i} = $mw->Button(
            -text => "$buttons[$i]",
            -width => '3',
            -height => '3',
            #-command => &numpress($i)) 
            )->pack(-anchor => 'nw', -side => 'top');


}
MainLoop;

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Re: Re: Syntax error using Tk
by flyingmoose (Priest) on Feb 16, 2004 at 15:43 UTC
    All true. I would also recommend using 'grid' instead of pack to create a better calculator-style layout.

    Also the usage of assigning $buttons[$i] as a Button and overiding the value of the text value $button[$i] forever seems to be a little odd. It will work, but I find it a little odd.

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      I've taken your advice and looked into Grid and believe it to be a better choice altogether. I've done a bit of reading and came up with this code but it goes into a continuous loop???
      my $row = 0;
my $column = 0;

for (my $i = 9; $i >= 0; $i--) 
{
$button{$i} = $mw->Button(-text    => "$i", 
                          -width   => '3', 
                          -height  => '1', 
                          -command => &numpress($i))
                   ->grid(-row     => $row,
                          -column  => $column);

$column++;
if($column > 2){$column = 0; $row++;}
}


MainLoop;

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      Any Ideas???

      Cheers, Eoin...
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        Now the problem is here: 
           -command => &numpress($i))

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        The thing being assigned to the "-command" attribute needs to be an anonymous subroutine, a reference to a named subroutine, or else a reference to an array whose elements are: named_subroutine_ref, arg1(, arg2 ...) -- in other words, either of the following would be the right way to do what you want: 
           -command => sub { numpress( $i ) }
# or
   -command => [ \&numpress, $i ]

        [download]
        The way you had it written, your subroutine is actually being called when the Button is being created, and Perl/Tk is trying to use the return value of the sub as the value for "-command" -- not good.
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