Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

At a certain part of my program, I call an error_check function to see if any errors have occured during some events. An example would be as follows: 
@reducedProtein = initializeStructure   ##some operations(\@residueArr
+ay,\@secondaryStructureArray);

if ($ERRORCHECK ==1)          #if global errorcheck is 1
{$response = confirmExit(@ERRORTYPE);} #call error function

if($response==1){        
simulate(@reducedProtein);} #if not, go to calculations etc

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Now the confirmExit is a function that calls a perlTK widget to create a window. It has two buttons. One is an exit button and exits the program if it is pressed. Other is an ignore button that returns a $response telling that the program can go on. My question is, how can I cause the program to stop until the user presses one of the buttons? I want it so that the program has to wait for the return value from the confirmExit to continue but I know perlTK works in a strange way. I think that it will just create the window with the buttons and return an empty value without waiting for the user to press a button. The skeleton of the confirmExit function is : 
sub confirmExit
 {
 *create a window*

 my @ERRORTYPE=@_;

 *write something on the window according to errortype values*

 *create button exit, which exits the program when pressed*

 *create button ignore, which sets the value of $response to 0 if pres
+sed*

 return $reponse;

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Replies are listed 'Best First'.
Re: Stopping the Program
by dirving (Friar) on Jun 21, 2008 at 01:17 UTC

    What you want is a modal dialog. In Tk, you can achieve this using Tk::Dialog (text and buttons only) or Tk::DialogBox (allows you to add any widgets you want).

    -- David Irving
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Re: Stopping the Program
by pc88mxer (Vicar) on Jun 21, 2008 at 01:09 UTC
    You can execute the dialog in another process and just wait for that process to finish: 
    sub check_errors {
  return unless ($ERRORCHECK == 1);
  my $st = system("ask-yes-no", "There were errors. Do you want to con
+tinue?") >> 8;
  if ($st != 0) {
    # exit the program
  }
}

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    And in your program: 
    ...do stuff...
check_errors();
...do more stuff...
check_errors();
... etc.

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    Update: See this article: CLI Magic: Creating basic front ends with dialog and Xdialog for more info on this approach. You may not even have to write the dialog application.

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Re: Stopping the Program
by zentara (Cardinal) on Jun 21, 2008 at 11:33 UTC
    This ought to show you a way. 
    #!/usr/bin/perl
use warnings;
use strict;
use Tk;
require Tk::Dialog;

my $result = 'Starting';

my $we_top = new MainWindow;

my $message = "Starting Ok ?\n";
my $count = 1;

$we_top->Label ( -text => $message)->pack();

my $count_lab = $we_top->Label ( 
          -textvariable => \$count)->pack();


my $okay_button =
   $we_top->Button( -text => 'Get Response',
                   -command => [\&get_response, $result]
                )->pack();

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

$we_top->MainLoop;

##########################################
sub analyze_response {
   my $answer = shift;

   if( $answer eq 'Yes' ){
       $result = "Continue at count $count ?";
    }

   if( $answer eq 'No' ){
       $result = "Rerun ?";
    }

   if( $answer eq 'Cancel' ){
       $result = "Cancelled ?";
    }
}

###########################################
sub get_response {
  my $answer = do_dialog();
  $count++; 
  print "$answer\n";
  &analyze_response( $answer  );

}


sub do_dialog {
 my $dlg = $we_top->Dialog(
    -title=>"Here is a question for you.",
    -buttons => ["Cancel", "No", "Yes"],
    -default_button => "No",
    -text => $result,
    -font => "Helvetica"
  );
my  $return = $dlg->Show();

return $return;

 }

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    I'm not really a human, but I play one on earth CandyGram for Mongo
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