Re: Die vs. Exit

I want the code to stop, let the user make some modifications to the input in the main window and then try again without completely shutting down the program.

Here's a piece of working code that does just that:

#!/usr/bin/env perl

use strict;
use warnings;

use Tk;

my $mw = MainWindow->new();

$mw->Label(-text => 'Enter integers only:')->pack;
$mw->Entry(
    -validate => 'key',
    -validatecommand => sub { $_[0] =~ /^\d+$/ },
    -invalidcommand => \&lam_num_error,
)->pack;

$mw->Button(-text => 'Exit', -command => sub { exit })->pack;

MainLoop;

sub lam_num_error {
    $mw->messageBox(-message=>"The input must be an integer.");
}
[download]

This is very basic and is only intended to show an example of Tk::Entry Validation. As it is, it only allows positive integers: you may want to change that.

Note that there's no die or exit in lam_num_error(). An Exit button is provided for users to quit the application.

-- Ken

Comment on Re: Die vs. Exit Select or Download Code

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Re^2: Die vs. Exit by shortyfw06 (Beadle) on Jul 20, 2012 at 22:32 UTC
This is an excellent example - exactly what I'm try to do! Thank you very much!	[reply]
Re^3: Die vs. Exit by shortyfw06 (Beadle) on Jul 20, 2012 at 23:14 UTC
I'm having trouble figuring out the regular expression for integers, positive or negative? `/^-?\d+$/` [download] Can someone please explain what the characters mean? I may have better luck figuring it out with a good explanation? Thanks!	[reply] [d/l]
Re^4: Die vs. Exit by kcott (Archbishop) on Jul 21, 2012 at 01:02 UTC
YAPE::Regex::Explain provides a good explanation: $ perl -E ' use YAPE::Regex::Explain; my $e = YAPE::Regex::Explain->new(q{^-?\d+$})->explain; say $e; ' The regular expression: (?-imsx:^-?\d+$) matches as follows: NODE EXPLANATION ---------------------------------------------------------------------- (?-imsx: group, but do not capture (case-sensitive) (with ^ and $ matching normally) (with . not matching \n) (matching whitespace and # normally): ---------------------------------------------------------------------- ^ the beginning of the string ---------------------------------------------------------------------- -? '-' (optional (matching the most amount possible)) ---------------------------------------------------------------------- \d+ digits (0-9) (1 or more times (matching the most amount possible)) ---------------------------------------------------------------------- $ before an optional \n, and the end of the string ---------------------------------------------------------------------- ) end of grouping ---------------------------------------------------------------------- [download] I'd also recommend the following documentation: perlrequick - Perl regular expressions quick start perlretut - Perl regular expressions tutorial perlre - Perl regular expressions -- Ken	[reply] [d/l]