The -font => '{arial} 18 {bold}' syntax seems pretty clean, but from my experience, setting the font with fontCreate always resulted in fewer glitches.

got it, thanks, zentara.

All,

I have changed up the code considerably, though the intent remains the same: validate text input intended for a MAC address. The most significant change is that I did away with using Tk::Entry validation, and instead am using bind subroutines to validate. I did this b/c I didn't like how if the user enters invalid text, it would not appear in the field (and I couldn't figure out how to insert it w/out breaking validation). Not only would users not see the invalid character that was entered, but they would have to back-space and delete the last visible character in the field in order to re-engage validation, even though the last displayed character in the field IS valid.

I've also added a Save button which will validate all the individual Entry fields in one fell swoop. If all the MAC input fields validate, then the new MAC is printed in a separate ROText widget.

Also, I've added a drop-down (Tk::Optionmenu) widget to allow selecting b/t multiple NICs; whichever is selected is the "current" NIC, as far as the MAC input fields are concerned.

For the most part, I happy, but after all my changes, I now have two new Tab issues, neither of which I've been able to solve, so here I am.

Problem 1:
When the app first starts up, I use eventGenerate bindings (to Tab and KeyRelease) to automatically tab thru all the MAC input fields and "auto-validate" the initial values. It works great, but if a bad octet is discovered, it will still continue to validate all the subsequent octets. That is not to say that the focus will tab thru the rest of the input fields, focus will properly halt on the input field with the bad value - it is just that the auto-validation attempts to continue in the background (i.e., if octet #3 is bad, it will have validation checked 4 times - as shown in the terminal when run). I can't figure out how to make it stop after the first failed validation (if any are discovered).

Problem 2:
I can't keep the Tab order in the way I want it. It should go:

NIC-Oct1->O2->O3->O4->O5->O6->Save

but instead, it goes:

NIC->Save->Oct1->O2->O3->O4->O5->O6

I have tried using this convention: 
my %after = (
  $NIC => $O1,
  $O1 => $O2,
  $O2 => $O3,
  $O3 => $O4,
  $O4 => $O5,
  $O5 => $O6,
  $O6 => $Save,
);
$mw->bind('all','<Tab>',sub{($after{$_[0]})->focus;Tk::break()});

[download]
But that breaks validation. I'm sure it has something to do with the way I am willy nilly disabled/enabling the -state and -takefocus options of the widgets, but I can't see the light.

<<<<<<>>>>>>>

Here's the new code: 
#!/usr/bin/perl
use strict;
use warnings;
use Tk;
use Tk::ROText;

# set to `0' if you do not want the actual MACs of detected NICs to be
+ used
# if set to `1', will gracefully/silently be ignored if no NICs are de
+tected
my $use_real_macs = 1;

# get NICs available to system
opendir(DIR,'/sys/class/net') or die "can't opendir '/sys/class/net': 
+$!\n";
my @nics = sort grep{!/lo/ && !/^\.\.?$/} readdir(DIR);
closedir(DIR);

# define some NICs (for display purposes) if none are found
unless($#nics>=0){
  @nics = ('eth0','eth1');
  $use_real_macs = 0;
}

my $mw = MainWindow->new(-title => 'MAC Address Tool');

$mw->fontCreate('sans_8',
  -family => 'sans',
  -weight => 'normal',
  -size   => 8,
);

$mw->fontCreate('mono',
  -family => 'mono',
  -weight => 'bold',
  -size   => 12,
);

my $fr1 = $mw->Frame()->pack(-expand => 1, -fill => 'both');
my $lb1 = $fr1->Label(-text => 'Select NIC')->pack(-side=>'left');

# hash to store MAC addresses saved, per NIC
my %macs = ();

# default val of the text variable that represents the currently selec
+ted NIC
my $nic = $nics[0];

# NIC drop-down menu
my $nicWidget = $fr1->Optionmenu(
  -font             => '{verdana} 10 {normal}',
  -bg               => 'white',
  -foreground       => 'Gray50',
  -activebackground => 'white',
  -options          => [@nics],
  -anchor           => 'w',
  -relief           => 'sunken',
  -bd               => 2,
  -padx             => 1,
  -takefocus        => 1,
  -textvariable     => \$nic,
)->pack(-side=>'left');

my $fr = $mw->Frame()->pack(-expand => 1, -fill => 'both');
my $lb = $fr->Label(-text => 'Enter MAC Address')->grid(-row=>0,-colum
+n=>0);

my $okBtn = $fr->Button(
  -text      => 'Save',
  -font      => 'sans_8',
  -state     => 'disabled',
  -bd        => 1,
  -takefocus => 0,
  -pady      => 5,
);

my %rot;
my $row = 3;
for(@nics){

  $fr->Label(-text=>$_.' MAC Address:')->grid(-row=>$row,-column=>0);
  $row++;

  $rot{$_} = $fr->ROText(
    -relief             => 'solid',
    -height             => 1,
    -width              => 18,
    -bg                 => 'white',
    -font               => 'mono',
    -foreground         => 'black',
    -bd                 => 1,
    -takefocus          => 0,
    -highlightthickness => 0,
    -state              => 'disabled',
  );

}

# widget used to display Entry field errors
my $errW = $fr->Label(-foreground=>'red');

# exit button
my $exitBtn = $fr->Button(
  -text      => 'Exit',
  -command   => sub {exit(0);},
  -font      => 'sans_8',
  -state     => 'normal',
  -bd        => 1,
  -takefocus => 0,
  -pady      => 5,
);

# hash to hold Entry widgets
my %entries;

# loop thru the number of Entry widgets desired
for(1..6){

  # create the Entry widget
  $entries{$_}{'entry'} = $fr->Entry(
    -font         => '{verdana} 12 {normal}',
    -textvariable => \$entries{$_}{'addy'},
    -width        => 3,
    -bg           => 'white',
  );

  # validate using bind
  $entries{$_}{'entry'}->bind('<KeyRelease>',[\&validation,$_,\%entrie
+s]);

  # save default widget background
  $entries{$_}{'bg'} = $entries{$_}{'entry'}->cget('-bg');

  # what type of validation will be done in this value
  $entries{$_}{'type'} = 'mac';

  # pack/display the widget
  $entries{$_}{'entry'}->grid(-row=>0,-column=>$_);

}

# see if we should use the actual MAC addresses
if($use_real_macs){

  # look up real MAC addresses
  for(@nics){
    my $file = '/sys/class/net/'.$_.'/address';
    open(FH,'<',$file) or die "can't open '$file': $!\n";
    my $address = readline(*FH);
    close(FH);
    die "Failed to get MAC for $_\n" unless($address);
    chomp($address);
    print "Real MAC address for $_: $address\n";
    my @address = split(/:/,$address);
    for(my $i=0;$i<=$#address;$i++){
      my $oct = $address[$i];
      $macs{$_}{$i+1} = $oct;
    }
  }

}else{

  # create some bogus MAC values (make values invalid to test validati
+on)
  for(sort keys %entries){
    $macs{$nic}{$_} = ($_>1) ? $_.$_ : '';
    $macs{$nic}{$_} .= 'z' if($_ == 3 or $_ == 4);
  }
}
# update MAC input fields at application start-up
&update_mac_fields;

# update MAC input fields whenever a new NIC is selected
$nicWidget->configure(-command => [\&update_mac_fields]);

# the Save button will validate *all* Entries
$okBtn->configure(-command => [ \&validate_all,\%entries ]);

# pack widgets based upon number of Entries
$errW->grid(-row=>1,-column=>1,-columnspan=>scalar keys %entries);
$okBtn->grid(-row=>2,-column=>(scalar keys %entries)-1,-columnspan=>2,
+-pady=>5);
$row = 3;
for(@nics){
  $rot{$_}->grid(-row=>$row,-column=>1,-columnspan=>scalar keys %entri
+es);
  $row++;
}
$exitBtn->grid(-row=>$row,-column=>(scalar keys %entries)-1,-columnspa
+n=>2,-pady=>5);

# auto-tab thru all Entry widgets to perform validation on pre-populat
+ed values
for(1..(scalar keys %entries) + 1){
  $mw->eventGenerate('<Tab>');
  $mw->eventGenerate('<KeyRelease>');
#  $mw->idletasks;
  $mw->after(100);
  $mw->update;
}

MainLoop();

sub update_mac_fields {
  for(sort keys %entries){
    $entries{$_}{'addy'} = $macs{$nic}{$_} ? $macs{$nic}{$_} : '';
    $entries{$_}{'entry'}->configure(-state=>'normal');
    $entries{$_}{'entry'}->configure(-bg=>$entries{$_}{'bg'});
  }
  $errW->configure(-text=>'');
  $okBtn->configure(-state=>'normal');
  $nicWidget->focus();
}

sub validate_all {
  my($ref) = @_;
  my $failed;
  my $empty;
  my $newmac;
  print "\nValidating all entries: \n";
  for(sort keys %$ref){

    # make sure field validates
    unless(&validation(undef,$_,$ref)){
      $failed = 1;
      last;
    }

    # make sure validated field is not empty
    my $octet = $ref->{$_}{'entry'}->get;
    unless($octet){
      $failed = 1;
      $empty = $_;
      last;
    }

    # concatenate the new MAC address
    $newmac .= ($newmac) ? ':'.$octet : $octet;

    # save to hash
    $macs{$nic}{$_} = $octet;
  }

  if($failed){
    if(defined($empty)){
      &validation_failed($empty,$ref,"Field \`$empty' cannot be empty"
+);
    }
  }else{
    $failed = 0;
    $rot{$nic}->configure(-state=>'normal');
    $rot{$nic}->delete('1.0','end');
    $rot{$nic}->insert('end',$newmac);
    $rot{$nic}->configure(-state=>'disabled');
  }
  return $failed;
}

# returns `1' if valid, and `0' if invalid
sub validation {
  my($self,$id,$ref) = @_;
  my $widget = defined($self) ? $self : $ref->{$id}{'entry'};
  my $value = $ref->{$id}{'addy'};
  my $type = $ref->{$id}{'type'};

  # boolean, 1 if validation is successful, 0 if fails
  my $valid;

  # see if any value was entered in the Entry widget field
  if($value){

    # get the index number of the last character in the value
    my $index = -1;
    if($self){$index++ while $value =~ /./g}

    print "Field $id ($type) index $index, val is \`",$value,"', valid
+ating...";

    # MAC address octet validation
    if($type eq 'mac'){
      if($index == 0){
        if($value =~ /^[0-9a-f]$/i){
          $valid = 1;
        }else{
          $valid = 0;
        }
      }elsif(($index == 1)||($index == -1)){
        if($value =~ /^[0-9a-f]{2}$/i){
          $valid = 1;
        }else{
          $valid = 0;
        }
      }else{
        $valid = 0;
      }

    # place-holder for other validation data types that are not define
+d yet
    }else{
      $valid = 1;
    }
    printf("%s\n",($valid) ? "ok" : "FAILED");

  # field must have been cleared or is empty (this is valid), clear ou
+t errors
  }else{
    print "Field $id ($type) has no value, resetting field...\n";
    $valid = 1;
  }

  if($valid){

    $widget->configure(-bg=>'white');

    # clear error widget
    &clear_err($id,$ref);

    # re-enable all other widgets
    for(sort keys %$ref){
      next if(/^$id$/);
      $ref->{$_}{'entry'}->configure(-state=>'normal');
    }

    # allow focus to NIC widget
    $nicWidget->configure(-takefocus=>1);

    # enable the Save button
# uncomment commented lines to implement a check for non-empty fields 
+first
#    my $empty;
#    for(sort keys %$ref){
#      unless($ref->{$_}{'entry'}->get){
#        $empty = 1;
#        last;
#      }
#    }
#    unless($empty){
      $okBtn->configure(-state=>'normal');
      $okBtn->configure(-takefocus=>1);
#    }

  }else{
    &validation_failed($id,$ref);
  }
  return $valid;
}

sub validation_failed {
  my($id,$ref,$errmsg) = @_;
  my $widget = $ref->{$id}{'entry'};
  my $value = $ref->{$id}{'addy'};

  $errmsg = "Field $id value \`$value' is invalid" unless($errmsg);

  # turn the background of the problem field to red
  $widget->configure(-bg=>'red');
  $widget->update();

  # update the error widget with text indicating a problem with the va
+lue
  $errW->configure(-text=>$errmsg);

  # temporarily disable focus on all other widgets
  for(sort keys %$ref){
    next if(/^$id$/);
    $ref->{$_}{'entry'}->configure(-state=>'disabled');
  }

  # disable the Save button
  $okBtn->configure(-state=>'disabled');
  $okBtn->configure(-takefocus=>0);

  # unfocus the Select NIC widget
  $nicWidget->configure(-takefocus=>0);

  $widget->focus();
}

sub clear_err {
  my($id,$ref) = @_;
  $errW->configure(-text=>'');
  $ref->{$id}{'entry'}->configure(-bg=>$ref->{$id}{'bg'});
}

[download]

Edit:
zentara,
I have a funny feeling that you are the only one still seeing this thread (i.e., the only monk I'm bugging)...maybe i'm just not good w/the forum views. can u tell me how I can view recently updated threads, or how do others know when a thread has been updated, if they aren't currently "subscribed" to it? Or is there no such thing?
Thanks!

In reply to Re^8: Tk::Entry and double-Tab key weirdness by atreyu
in thread Tk::Entry and double-Tab key weirdness by atreyu

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