| Commit | Line | Data |
|---|
| c07a80fd |
1 | package vars; |
| 2 | |
| fb73857a |
3 | require 5.002; |
| 4 | |
| 5 | # The following require can't be removed during maintenance |
| 6 | # releases, sadly, because of the risk of buggy code that does |
| 7 | # require Carp; Carp::croak "..."; without brackets dying |
| 8 | # if Carp hasn't been loaded in earlier compile time. :-( |
| 9 | # We'll let those bugs get found on the development track. |
| 10 | require Carp if $] < 5.00450; |
| 3d842d7f |
11 | |
| 12 | use warnings::register; |
| fb73857a |
13 | |
| 14 | sub import { |
| 15 | my $callpack = caller; |
| 16 | my ($pack, @imports, $sym, $ch) = @_; |
| 17 | foreach $sym (@imports) { |
| fb73857a |
18 | ($ch, $sym) = unpack('a1a*', $sym); |
| 014aafb8 |
19 | if ($sym =~ tr/A-Za-z_0-9//c) { |
| 15313f9c |
20 | # time for a more-detailed check-up |
| 21 | if ($sym =~ /::/) { |
| 22 | require Carp; |
| 23 | Carp::croak("Can't declare another package's variables"); |
| 24 | } elsif ($sym =~ /^\w+[[{].*[]}]$/) { |
| 25 | require Carp; |
| 26 | Carp::croak("Can't declare individual elements of hash or array"); |
| d3a7d8c7 |
27 | } elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) { |
| 28 | warnings::warn("No need to declare built-in vars"); |
| 15313f9c |
29 | } |
| 30 | } |
| fb73857a |
31 | *{"${callpack}::$sym"} = |
| 32 | ( $ch eq "\$" ? \$ {"${callpack}::$sym"} |
| 33 | : $ch eq "\@" ? \@ {"${callpack}::$sym"} |
| 34 | : $ch eq "\%" ? \% {"${callpack}::$sym"} |
| 35 | : $ch eq "\*" ? \* {"${callpack}::$sym"} |
| 36 | : $ch eq "\&" ? \& {"${callpack}::$sym"} |
| 37 | : do { |
| 38 | require Carp; |
| 15313f9c |
39 | Carp::croak("'$ch$sym' is not a valid variable name"); |
| fb73857a |
40 | }); |
| 41 | } |
| 42 | }; |
| 43 | |
| 44 | 1; |
| 45 | __END__ |
| 46 | |
| c07a80fd |
47 | =head1 NAME |
| 48 | |
| 86a9aef2 |
49 | vars - Perl pragma to predeclare global variable names (obsolete) |
| c07a80fd |
50 | |
| 51 | =head1 SYNOPSIS |
| 52 | |
| 53 | use vars qw($frob @mung %seen); |
| 54 | |
| 55 | =head1 DESCRIPTION |
| 56 | |
| 86a9aef2 |
57 | NOTE: The functionality provided by this pragma has been superseded |
| 58 | by C<our> declarations, available in Perl v5.6.0 or later. See |
| 59 | L<perlfunc/our>. |
| 60 | |
| c07a80fd |
61 | This will predeclare all the variables whose names are |
| 62 | in the list, allowing you to use them under "use strict", and |
| 63 | disabling any typo warnings. |
| 64 | |
| 55497cff |
65 | Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and |
| 66 | C<use subs> declarations are not BLOCK-scoped. They are thus effective |
| 67 | for the entire file in which they appear. You may not rescind such |
| 68 | declarations with C<no vars> or C<no subs>. |
| 69 | |
| 7a2e2cd6 |
70 | Packages such as the B<AutoLoader> and B<SelfLoader> that delay |
| 71 | loading of subroutines within packages can create problems with |
| 72 | package lexicals defined using C<my()>. While the B<vars> pragma |
| 73 | cannot duplicate the effect of package lexicals (total transparency |
| 74 | outside of the package), it can act as an acceptable substitute by |
| 75 | pre-declaring global symbols, ensuring their availability to the |
| 76 | later-loaded routines. |
| c6f23971 |
77 | |
| ee580363 |
78 | See L<perlmodlib/Pragmatic Modules>. |
| c07a80fd |
79 | |
| 80 | =cut |
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