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

Sorry venerable monks this has a lot of code and output but I have no idea why I'm getting the result I am. The sub routine sets up a group of Entry boxes and tries to add default values to the boxes which it extracts from a hash. This works unless the value I'm trying to insert is -1. In which case I get -1-1 any other value outputs fine and dandy. Does perl have a special meaning for -1 if so how can I get round the problem?
As a side note I had worked without problems with this sub for sometime, and it was only luck or bad luck that I came upon a parameter of -1 in the test data. 
sub build_param_input{
 
    my $params = @_;
    
    my $file =  SBSTESTFUNCTIONS::get_XML_file_name('FILE'=>"$program_
+name.pm");
    $params = SBSTESTFUNCTIONS::get_vars_hash('FILE'=>$file);
    
    print Dumper(\%$params); # testing
#output
#$VAR1 = {
#          'STOP_AFTER' => [
#                            'G2155_STOP',
#                            '-1',
#                            undef
#                          ],
#          'START_FROM' => [
#                            'G2155_START',
#                            '-1',
#                            undef
#                          ],
#          'RESPONSE' => [
#                          'G2155_RESPONS',
#                          'G2155_RESPONS',
#                          undef
#                        ],
#          'SERVICE' => [
#                         'G2155_SERVICE',
#                         'ENQSYSSV',
#                         undef
#                       ],
#          'SHARED' => [
#                        'G2155_SHARED',
#                        'Y',
#                        undef
#                      ]
#        };
    
    my $count;
    foreach my $key (keys(%$params)){
        $count++;
        my $name = $lf1->Entry(-textvariable=>$key);
        $name->insert('e',$key);
        my $pinput= $lf1->Entry(-textvariable=>$$params{$key}[1]);
        $pinput->insert('e',$$params{$key}[1]);#Inserts the -1-1 but o
+ther values OK.
        
        print "$$params{$key}[1]\n"; #to test
#Output to stdout
#-1
#-1
#G2155_RESPONS
#ENQSYSSV
#Y
        $name->grid(-row=>$count, -column=>1);
        $pinput->grid(-row=>$count, -column=>2);
    }
    $count = undef;
 }

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Replies are listed 'Best First'.
Re: Printing -1 in a Tk Entry.
by gri6507 (Deacon) on Jun 02, 2004 at 13:17 UTC
    It looks like you are creating an Entry per each hash entry. Each Entry has a textvariable associated with it, which puts the value from the hash into the Entry. You then insert the same value yet again into the Entry. I think you just need to get rid of the insert statement. I tried it on this code

    use Tk;
use strict;

my %params = (
              a => [
                    "blah1",
                    "hello"
                   ],
              b => [
                    "blah2",
                    "-1"
                   ]
             );

my $mw = MainWindow->new(-title => 'Play w/form');
foreach my $key (keys(%params)){
  my $entry = $mw->Entry(-textvariable=>\$params{$key}[1])->pack();
  #$entry->insert('e',$params{$key}[1]); #unnecessary insert
}

MainLoop;

    [download]
[reply]
[d/l]
      I've tried this and nothing appears in the Entry box. As I understand it the -textvariable=>$var asscociates the value typed in, to the variable $var but does not display it.
[reply]
        Your understanding is incorrect. Take a look here.
[reply]
Re: Printing -1 in a Tk Entry.
by zentara (Cardinal) on Jun 02, 2004 at 13:16 UTC
    It would be helpful if you could post a small working program that demonstrates your problem.
    I'm not really a human, but I play one on earth. flash japh
[reply]
      Thanks to both replies I have found the answer but there was still something weird going on. The fault lay in the fact that the textvariable should be a reference to variable not $$params{$key}1 as i had used however why this only doubled up the -1 I still have no idea. I tried to replicate the behavior in a small prog but found I could not get the same result. Thanks for your considerations
[reply]

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