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- 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- functionality provided by this pragma has been superseded by C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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