85 lines
2.4 KiB
Perl
85 lines
2.4 KiB
Perl
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package vars;
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use 5.006;
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our $VERSION = '1.05';
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use warnings::register;
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use strict qw(vars subs);
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sub import {
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my $callpack = caller;
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my (undef, @imports) = @_;
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my ($sym, $ch);
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foreach (@imports) {
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if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) {
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if ($sym =~ /\W/) {
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# time for a more-detailed check-up
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if ($sym =~ /^\w+[[{].*[]}]$/) {
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require Carp;
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Carp::croak("Can't declare individual elements of hash or array");
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} elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) {
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warnings::warn("No need to declare built-in vars");
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} elsif (($^H & strict::bits('vars'))) {
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require Carp;
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Carp::croak("'$_' is not a valid variable name under strict vars");
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}
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}
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$sym = "${callpack}::$sym" unless $sym =~ /::/;
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*$sym =
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( $ch eq "\$" ? \$$sym
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: $ch eq "\@" ? \@$sym
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: $ch eq "\%" ? \%$sym
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: $ch eq "\*" ? \*$sym
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: $ch eq "\&" ? \&$sym
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: do {
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require Carp;
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Carp::croak("'$_' is not a valid variable name");
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});
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} else {
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require Carp;
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Carp::croak("'$_' is not a valid variable name");
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}
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}
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};
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1;
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__END__
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=head1 NAME
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vars - Perl pragma to predeclare global variable names
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=head1 SYNOPSIS
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use vars qw($frob @mung %seen);
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=head1 DESCRIPTION
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NOTE: For use with variables in the current package for a single scope, the
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functionality provided by this pragma has been superseded by C<our>
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declarations, available in Perl v5.6.0 or later, and use of this pragma is
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discouraged. See L<perlfunc/our>.
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This pragma will predeclare all the variables whose names are
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in the list, allowing you to use them under C<use strict>, and
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disabling any typo warnings for them.
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Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and
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C<use subs> declarations are not lexically scoped to the block they appear
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in: they affect
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the entire package in which they appear. It is not possible to rescind these
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declarations with C<no vars> or C<no subs>.
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Packages such as the B<AutoLoader> and B<SelfLoader> that delay
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loading of subroutines within packages can create problems with
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package lexicals defined using C<my()>. While the B<vars> pragma
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cannot duplicate the effect of package lexicals (total transparency
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outside of the package), it can act as an acceptable substitute by
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pre-declaring global symbols, ensuring their availability to the
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later-loaded routines.
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See L<perlmodlib/Pragmatic Modules>.
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=cut
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