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920dae64 AT |
1 | package vars; |
2 | ||
3 | use 5.006; | |
4 | ||
5 | our $VERSION = '1.01'; | |
6 | ||
7 | use warnings::register; | |
8 | use strict qw(vars subs); | |
9 | ||
10 | sub import { | |
11 | my $callpack = caller; | |
12 | my ($pack, @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 | ||
46 | 1; | |
47 | __END__ | |
48 | ||
49 | =head1 NAME | |
50 | ||
51 | vars - Perl pragma to predeclare global variable names (obsolete) | |
52 | ||
53 | =head1 SYNOPSIS | |
54 | ||
55 | use vars qw($frob @mung %seen); | |
56 | ||
57 | =head1 DESCRIPTION | |
58 | ||
59 | NOTE: For variables in the current package, the functionality provided | |
60 | by this pragma has been superseded by C<our> declarations, available | |
61 | in Perl v5.6.0 or later. See L<perlfunc/our>. | |
62 | ||
63 | This will predeclare all the variables whose names are | |
64 | in the list, allowing you to use them under "use strict", and | |
65 | disabling any typo warnings. | |
66 | ||
67 | Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and | |
68 | C<use subs> declarations are not BLOCK-scoped. They are thus effective | |
69 | for the entire file in which they appear. You may not rescind such | |
70 | declarations with C<no vars> or C<no subs>. | |
71 | ||
72 | Packages such as the B<AutoLoader> and B<SelfLoader> that delay | |
73 | loading of subroutines within packages can create problems with | |
74 | package lexicals defined using C<my()>. While the B<vars> pragma | |
75 | cannot duplicate the effect of package lexicals (total transparency | |
76 | outside of the package), it can act as an acceptable substitute by | |
77 | pre-declaring global symbols, ensuring their availability to the | |
78 | later-loaded routines. | |
79 | ||
80 | See L<perlmodlib/Pragmatic Modules>. | |
81 | ||
82 | =cut |