package vars;
use 5.006;
our $VERSION = '1.03';
use warnings::register;
use strict qw(vars subs);
sub import {
my $callpack = caller;
my (undef, @imports) = @_;
my ($sym, $ch);
foreach (@imports) {
if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) {
if ($sym =~ /\W/) {
# time for a more-detailed check-up
if ($sym =~ /^\w+[[{].*[]}]$/) {
require Carp;
Carp::croak("Can't declare individual elements of hash or array");
} elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) {
warnings::warn("No need to declare built-in vars");
} elsif (($^H &= strict::bits('vars'))) {
require Carp;
Carp::croak("'$_' is not a valid variable name under strict vars");
}
}
$sym = "${callpack}::$sym" unless $sym =~ /::/;
*$sym =
( $ch eq "\$" ? \$$sym
: $ch eq "\@" ? \@$sym
: $ch eq "\%" ? \%$sym
: $ch eq "\*" ? \*$sym
: $ch eq "\&" ? \&$sym
: do {
require Carp;
Carp::croak("'$_' is not a valid variable name");
});
} else {
require Carp;
Carp::croak("'$_' is not a valid variable name");
}
}
};
1;
__END__
=head1 NAME
vars - Perl pragma to predeclare global variable names
=head1 SYNOPSIS
use vars qw($frob @mung %seen);
=head1 DESCRIPTION
NOTE: For use with variables in the current package for a single scope, the
functionality provided by this pragma has been superseded by C<our>
declarations, available in Perl v5.6.0 or later, and use of this pragma is
discouraged. See L<perlfunc/our>.
This will predeclare all the variables whose names are
in the list, allowing you to use them under "use strict", and
disabling any typo warnings.
Unlike pragmas that affect the C<$^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
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