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   1  package vars;
   2  
   3  use 5.006;
   4  
   5  our $VERSION = '1.01';
   6  
   7  use warnings::register;
   8  use strict qw(vars subs);
   9  
  10  sub import {
  11      my $callpack = caller;
  12      my ($pack, @imports) = @_;
  13      my ($sym, $ch);
  14      foreach (@imports) {
  15          if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) {
  16          if ($sym =~ /\W/) {
  17          # time for a more-detailed check-up
  18          if ($sym =~ /^\w+[[{].*[]}]$/) {
  19              require Carp;
  20              Carp::croak("Can't declare individual elements of hash or array");
  21          } elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) {
  22              warnings::warn("No need to declare built-in vars");
  23          } elsif  (($^H &= strict::bits('vars'))) {
  24              require Carp;
  25              Carp::croak("'$_' is not a valid variable name under strict vars");
  26          }
  27          }
  28          $sym = "$callpack}::$sym" unless $sym =~ /::/;
  29          *$sym =
  30          (  $ch eq "\$" ? \$$sym
  31           : $ch eq "\@" ? \@$sym
  32           : $ch eq "\%" ? \%$sym
  33           : $ch eq "\*" ? \*$sym
  34           : $ch eq "\&" ? \&$sym 
  35           : do {
  36               require Carp;
  37               Carp::croak("'$_' is not a valid variable name");
  38           });
  39      } else {
  40          require Carp;
  41          Carp::croak("'$_' is not a valid variable name");
  42      }
  43      }
  44  };
  45  
  46  1;
  47  __END__
  48  
  49  =head1 NAME
  50  
  51  vars - Perl pragma to predeclare global variable names (obsolete)
  52  
  53  =head1 SYNOPSIS
  54  
  55      use vars qw($frob @mung %seen);
  56  
  57  =head1 DESCRIPTION
  58  
  59  NOTE: For variables in the current package, the functionality provided
  60  by this pragma has been superseded by C<our> declarations, available
  61  in Perl v5.6.0 or later.  See L<perlfunc/our>.
  62  
  63  This will predeclare all the variables whose names are 
  64  in the list, allowing you to use them under "use strict", and
  65  disabling any typo warnings.
  66  
  67  Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and
  68  C<use subs> declarations are not BLOCK-scoped.  They are thus effective
  69  for the entire file in which they appear.  You may not rescind such
  70  declarations with C<no vars> or C<no subs>.
  71  
  72  Packages such as the B<AutoLoader> and B<SelfLoader> that delay
  73  loading of subroutines within packages can create problems with
  74  package lexicals defined using C<my()>. While the B<vars> pragma
  75  cannot duplicate the effect of package lexicals (total transparency
  76  outside of the package), it can act as an acceptable substitute by
  77  pre-declaring global symbols, ensuring their availability to the
  78  later-loaded routines.
  79  
  80  See L<perlmodlib/Pragmatic Modules>.
  81  
  82  =cut