1package vars;
2
3use 5.006;
4
5our $VERSION = '1.05';
6
7use warnings::register;
8use strict qw(vars subs);
9
10sub import {
11    my $callpack = caller;
12    my (undef, @imports) = @_;
13    my ($sym, $ch);
14    foreach (@imports) {
15        if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) {
16	    if ($sym =~ /\W/) {
17		# time for a more-detailed check-up
18		if ($sym =~ /^\w+[[{].*[]}]$/) {
19		    require Carp;
20		    Carp::croak("Can't declare individual elements of hash or array");
21		} elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) {
22		    warnings::warn("No need to declare built-in vars");
23		} elsif  (($^H & strict::bits('vars'))) {
24		    require Carp;
25		    Carp::croak("'$_' is not a valid variable name under strict vars");
26		}
27	    }
28	    $sym = "${callpack}::$sym" unless $sym =~ /::/;
29	    *$sym =
30		(  $ch eq "\$" ? \$$sym
31		 : $ch eq "\@" ? \@$sym
32		 : $ch eq "\%" ? \%$sym
33		 : $ch eq "\*" ? \*$sym
34		 : $ch eq "\&" ? \&$sym
35		 : do {
36		     require Carp;
37		     Carp::croak("'$_' is not a valid variable name");
38		 });
39	} else {
40	    require Carp;
41	    Carp::croak("'$_' is not a valid variable name");
42	}
43    }
44};
45
461;
47__END__
48
49=head1 NAME
50
51vars - Perl pragma to predeclare global variable names
52
53=head1 SYNOPSIS
54
55    use vars qw($frob @mung %seen);
56
57=head1 DESCRIPTION
58
59NOTE: For use with variables in the current package for a single scope, the
60functionality provided by this pragma has been superseded by C<our>
61declarations, available in Perl v5.6.0 or later, and use of this pragma is
62discouraged.  See L<perlfunc/our>.
63
64This pragma will predeclare all the variables whose names are
65in the list, allowing you to use them under C<use strict>, and
66disabling any typo warnings for them.
67
68Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and
69C<use subs> declarations are not lexically scoped to the block they appear
70in: they affect
71the entire package in which they appear.  It is not possible to rescind these
72declarations with C<no vars> or C<no subs>.
73
74Packages such as the B<AutoLoader> and B<SelfLoader> that delay
75loading of subroutines within packages can create problems with
76package lexicals defined using C<my()>. While the B<vars> pragma
77cannot duplicate the effect of package lexicals (total transparency
78outside of the package), it can act as an acceptable substitute by
79pre-declaring global symbols, ensuring their availability to the
80later-loaded routines.
81
82See L<perlmodlib/Pragmatic Modules>.
83
84=cut
85