You are using the constant.pm pragmatic incorrectly, and constants don't do what you think they do.

Correct syntax is,

use constant SCROLL_X => 1;
use constant SCROLL_Y => 2;
use constant FLOW_X   => 3;
use constant FLOW_Y   => 4;
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Update: As Abigail-II notes, recent constant.pm can take a hashref as argument. The syntax

use canstant {
    SCROLL_X => 1,
    SCROLL_Y => 2,
    FLOW_X   => 3,
    FLOW_Y   => 4,
};
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After Compline,
Zaxo

The OP was using constants correctly. She's just using a modern version of Perl.

Abigail

In 5.8.1, $ perl -e'use constant { FOO = 1, BAR = 2}; print FOO,BAR' does not compile. With stringy commas, the combined form does work,

$ perl -e'use constant { FOO => 1, BAR => 2}; print FOO,BAR'
12$
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'1' and '3' are not legal names for subs.

After Compline,
Zaxo

Abigail, I'm male!! :))))))))
And folks, please forget about the syntax!! Everything I code with constants work( as you all pointed out), and thanks :))))
The question still remains unanswered! Any ideas?? I know how to solve the problem. I just have a feeling that it is not the perl way!
Ogla

Well, you could do something along these lines:

{
my @constants = qw(scroll_x scroll_y flow_x flow_y);
sub which_constants {
  my $self = shift;
  return undef unless ref($self);
  my %hashtest;
  @hashtest{map { $_ - 1 } grep(/^\d+$/ && 0<=$_ && $_<@constants,@_)}
+ = ();
  $self->{$constants[$_]} = exists $hashtest{$_} ? 1:0 for (0..$#const
+ants);
  $self;
}
}
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Of course, I'm assuming that your object is a blessed hashref. Is it pretty? Nope. But it does work and...ummm...yep. Hope this helps.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

Thanks antirice!
Yes they're all blessed hashrefs. I'll work on it. For me it's very pretty.Any code containing this triplet "grep,map, hash slice" has the "coolness factor". :))))))
Ogla

sub UNIVERSAL::which_constants {
  my($class, @constants) = @_;

  return grep exists $constant::declared{"$class\::$_"}, @constants;
}
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_________
broquaint

broquaint, I respect you very much. However, I was just wondering if you were aware that @constants will contain numbers and that you'll be checking whether or not a constant by that name exists...which it won't. Of course, you could declare the constants as X => "X" instead of X=>number to get it to work. I dunno. It's 4am and am being a bit dense I guess. :-/

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

that @constants will contain numbers and that you'll be checking whether or not a constant by that name exists...which it won't.

Hmm, well maybe my function doesn't do what the OP requested (quite possible since it was written pre-1pm ;) but it will do what I intended - given a list of strings return if they exist in a given package e.g

sub UNIVERSAL::which_constants {
  my($class, @constants) = @_;

  return grep exists $constant::declared{"$class\::$_"}, @constants;
}

use constant FOO => "a string";
use constant BAR => [ qw/ an array / ];
use constant BAZ => { qw/ a hash / };

print "constant exists - $_\n"
  for main->which_constants( qw/ ichi FOO bar BAZ one DEUX / );

__output__

constant exists - FOO
constant exists - BAZ
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And if you want to go from constant values to constant names then check out chromatic's Devel::Constants module.
HTH

_________
broquaint