| | 1 | package vars; |
| | 2 | |
| | 3 | use 5.006; |
| | 4 | |
| | 5 | our $VERSION = '1.03'; |
| | 6 | |
| | 7 | use warnings::register; |
| | 8 | use strict qw(vars subs); |
| | 9 | |
| | 10 | sub 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 | |
| | 46 | 1; |
| | 47 | __END__ |
| | 48 | |
| | 49 | =head1 NAME |
| | 50 | |
| | 51 | vars - Perl pragma to predeclare global variable names |
| | 52 | |
| | 53 | =head1 SYNOPSIS |
| | 54 | |
| | 55 | use vars qw($frob @mung %seen); |
| | 56 | |
| | 57 | =head1 DESCRIPTION |
| | 58 | |
| | 59 | NOTE: For use with variables in the current package for a single scope, the |
| | 60 | functionality provided by this pragma has been superseded by C<our> |
| | 61 | declarations, available in Perl v5.6.0 or later, and use of this pragma is |
| | 62 | discouraged. See L<perlfunc/our>. |
| | 63 | |
| | 64 | This will predeclare all the variables whose names are |
| | 65 | in the list, allowing you to use them under "use strict", and |
| | 66 | disabling any typo warnings. |
| | 67 | |
| | 68 | Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and |
| | 69 | C<use subs> declarations are not BLOCK-scoped. They are thus effective |
| | 70 | for the entire file in which they appear. You may not rescind such |
| | 71 | declarations with C<no vars> or C<no subs>. |
| | 72 | |
| | 73 | Packages such as the B<AutoLoader> and B<SelfLoader> that delay |
| | 74 | loading of subroutines within packages can create problems with |
| | 75 | package lexicals defined using C<my()>. While the B<vars> pragma |
| | 76 | cannot duplicate the effect of package lexicals (total transparency |
| | 77 | outside of the package), it can act as an acceptable substitute by |
| | 78 | pre-declaring global symbols, ensuring their availability to the |
| | 79 | later-loaded routines. |
| | 80 | |
| | 81 | See L<perlmodlib/Pragmatic Modules>. |
| | 82 | |
| | 83 | =cut |
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