vars.pm revision 7c478bd95313f5f23a4c958a745db2134aa03244
package vars;
require 5.002;
# The following require can't be removed during maintenance
# releases, sadly, because of the risk of buggy code that does
# require Carp; Carp::croak "..."; without brackets dying
# if Carp hasn't been loaded in earlier compile time. :-(
# We'll let those bugs get found on the development track.
require Carp if $] < 5.00450;
use warnings::register;
require strict;
sub import {
my $callpack = caller;
# time for a more-detailed check-up
if ($sym =~ /::/) {
require Carp;
Carp::croak("Can't declare another package's variables");
} elsif ($sym =~ /^\w+[[{].*[]}]$/) {
require Carp;
Carp::croak("Can't declare individual elements of hash or array");
warnings::warn("No need to declare built-in vars");
} elsif ( $^H &= strict::bits('vars') ) {
Carp::croak("'$ch$sym' is not a valid variable name under strict vars");
}
}
*{"${callpack}::$sym"} =
: do {
require Carp;
Carp::croak("'$ch$sym' is not a valid variable name");
});
}
};
1;
=head1 NAME
vars - Perl pragma to predeclare global variable names (obsolete)
=head1 SYNOPSIS
use vars qw($frob @mung %seen);
=head1 DESCRIPTION
NOTE: The functionality provided by this pragma has been superseded
by C<our> declarations, available in Perl v5.6.0 or later. See
This will predeclare all the variables whose names are
in the list, allowing you to use them under "use strict", and
disabling any typo warnings.
Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and
C<use subs> declarations are not BLOCK-scoped. They are thus effective
for the entire file in which they appear. You may not rescind such
declarations with C<no vars> or C<no subs>.
Packages such as the B<AutoLoader> and B<SelfLoader> that delay
loading of subroutines within packages can create problems with
package lexicals defined using C<my()>. While the B<vars> pragma
cannot duplicate the effect of package lexicals (total transparency
outside of the package), it can act as an acceptable substitute by
pre-declaring global symbols, ensuring their availability to the
later-loaded routines.
See L<perlmodlib/Pragmatic Modules>.
=cut