gallerymaker/modules/vars.pm
2014-12-11 21:58:53 -05:00

77 lines
2.3 KiB
Perl

package vars;
our $VERSION = '1.01';
use warnings::register;
use strict;
no strict 'refs';
sub import {
my $callpack = caller;
my ($pack, @imports) = @_;
my ($sym, $ch);
foreach (@imports) {
if (($ch, $sym) = m/^([\$\@\%\*\&])(.+)/) {
if ($sym =~ m/\W/) {
# time for a more-detailed check-up
if ($sym =~ m/^\w+[[{].*[]}]$/) {
die("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'))) {
die("'$_' is not a valid variable name under strict vars");
}
}
$sym = "{$callpack}::$sym" unless $sym =~ m/::/;
*{Symbol::fetch_glob($sym)} =
( $ch eq "\$" ? \${*{Symbol::fetch_glob($sym)}}
: $ch eq "\@" ? \@{*{Symbol::fetch_glob($sym)}}
: $ch eq "\%" ? \%{*{Symbol::fetch_glob($sym)}}
: $ch eq "\*" ? \*{Symbol::fetch_glob($sym)}
: $ch eq "\&" ? \&{*{Symbol::fetch_glob($sym)}}
: die("'$_' is not a valid variable name")
);
} else {
die("'$_' is not a valid variable name");
}
}
};
1;
__END__
=head1 NAME
vars - Perl pragma to predeclare global variable names (obsolete)
=head1 SYNOPSIS
use vars qw($frob @mung %seen);
=head1 DESCRIPTION
NOTE: For variables in the current package, the functionality provided
by this pragma has been superseded by C<our> declarations, available
in Perl v5.6.0 or later. See L<perlfunc/our>.
This will predeclare all the variables whose names are
in the list, allowing you to use them under "use strict", and
disabling any typo warnings.
Unlike pragmas that affect the C<$^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