Another option is to use the AUTOLOAD feature, and determine valid tag toggles using a hash rather than an array (although there's no reason you couldn't generate the former from the latter)...

my %state = (
  name    => 0, # default states
  gender  => 0,
  address => 0,
);

sub AUTOLOAD {
  my $tag = $AUTOLOAD;
     $tag =~ s/^.*:://;

  my $turn_off = $tag =~ s/_$//;

    # Only keep track of tags we want.
  return unless exists $state{$tag};

  $state{$tag} = $turn_off ? 0 : 1;

    # Do something that uses %state
  whatever();
}
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    --k.

my @list = qw/foo bar baz/;
foreach my $element (@list) {
  *{$element} = sub {
    $state{$element} = 1;
  };
  *{"${element}_"} = sub {
    $state{$element} = 0;
  };
}
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If you are using strict {insert standard admonition here} you'd need to use:

no strict 'refs';
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On another note, without knowing just what your goal is, there is likely another XML module that might do more of what you need for you. A search at search.cpan.org for "XML" returns over 2000 matches. :)

UPDATE: Added the missing semi-colons. Thanks to esh for pointing out they were missing. :)

- Matt Riffle

Slight syntax correction to mattriff's cool code. You'll need to terminate the assignments with semicolons. (Well, this being Perl, you just need to separate them with semicolons, but let's pretend it's terminate so we don't run into problems the next time we add a statement).

my @list = qw/foo bar baz/;
foreach my $element (@list) {
  *{$element} = sub {
    $state{$element} = 1;
  };
  *{"${element}_"} = sub {
    $state{$element} = 0;
  };
}
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-- Eric Hammond

Although I really like the AUTOLOAD approach, I've used a different method in the past.

WARNING: The following code could cause nasty personal side effects, not limited to people running when they see you.

my @tags= qw/name gender address/;

foreach my $t (@tags)
 {
  eval "sub $t { \$state{'$name'} = 1; }";
  eval "sub ${t}_ { \$state{'$name'} = 1; }";
 }
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Of course, if you find that one too disgusting. You could always run a loop once to write the appropriate code to a Perl module file and then use that file.

BEGIN
 {
  unless(-e "Tags.pm")
  {
    my @tags= qw/name gender address/;

    open( F, ">Tags.pm" )
              or die "Unable to create Tags.pm:$!";

    foreach my $t (@tags)
     {
      print F "sub $t { \$state{'$name'} = 1; }\n";
      print F "sub ${t}_ { \$state{'$name'} = 1; }\n";
     }
    print F "1;\n";
    close( F ) or die "Unable to close Tags.pm:$!";
   }
 }

use Tags;
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Ain't code that writes code a wonderful thing.

Update: I forgot to add the "1;" at the end.

G. Wade

many thanks for everybody's help. Worked a dream.