package vars; use 5.006; our $VERSION = '1.05'; 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($frob @mung %seen); =head1 DESCRIPTION NOTE: For use with variables in the current package for a single scope, the functionality provided by this pragma has been superseded by C<our> declarations, available in Perl v5.6.0 or later, and use of this pragma is discouraged. See L<perlfunc/our>. This pragma will predeclare all the variables whose names are in the list, allowing you to use them under C<use strict>, and disabling any typo warnings for them. Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and C<use subs> declarations are not lexically scoped to the block they appear in: they affect the entire package in which they appear. It is not possible to rescind these 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