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c07a80fd |
1 | package vars; |
2 | |
3 | =head1 NAME |
4 | |
5 | vars - Perl pragma to predeclare global variable names |
6 | |
7 | =head1 SYNOPSIS |
8 | |
9 | use vars qw($frob @mung %seen); |
10 | |
11 | =head1 DESCRIPTION |
12 | |
13 | This will predeclare all the variables whose names are |
14 | in the list, allowing you to use them under "use strict", and |
15 | disabling any typo warnings. |
16 | |
c6f23971 |
17 | Packages such as the B<AutoLoader> and B<SelfLoader> that delay loading |
18 | of subroutines within packages can create problems with package lexicals |
19 | defined using C<my()>. While the B<vars> pragma cannot duplicate the |
20 | effect of package lexicals (total transparency outside of the package), |
21 | it can act as an acceptable substitute by pre-declaring global symbols, |
22 | ensuring their availability to to the later-loaded routines. |
23 | |
c07a80fd |
24 | See L<perlmod/Pragmatic Modules>. |
25 | |
26 | =cut |
27 | require 5.000; |
28 | use Carp; |
29 | |
30 | sub import { |
31 | my $callpack = caller; |
32 | my ($pack, @imports, $sym, $ch) = @_; |
33 | foreach $sym (@imports) { |
34 | croak "Can't declare another package's variables" if $sym =~ /::/; |
35 | ($ch, $sym) = unpack('a1a*', $sym); |
36 | *{"${callpack}::$sym"} = |
37 | ( $ch eq "\$" ? \$ {"${callpack}::$sym"} |
38 | : $ch eq "\@" ? \@ {"${callpack}::$sym"} |
39 | : $ch eq "\%" ? \% {"${callpack}::$sym"} |
40 | : $ch eq "\*" ? \* {"${callpack}::$sym"} |
41 | : $ch eq "\&" ? \& {"${callpack}::$sym"} |
42 | : croak "'$ch$sym' is not a valid variable name\n"); |
43 | } |
44 | }; |
45 | |
46 | 1; |