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Diffstat (limited to 'Master/tlpkg/tlperl/lib/vars.pm')
-rw-r--r-- | Master/tlpkg/tlperl/lib/vars.pm | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/vars.pm b/Master/tlpkg/tlperl/lib/vars.pm new file mode 100644 index 00000000000..a0151b84030 --- /dev/null +++ b/Master/tlpkg/tlperl/lib/vars.pm @@ -0,0 +1,82 @@ +package vars; + +use 5.006; + +our $VERSION = '1.01'; + +use warnings::register; +use strict qw(vars subs); + +sub import { + my $callpack = caller; + my ($pack, @imports) = @_; + my ($sym, $ch); + foreach (@imports) { + if (($ch, $sym) = /^([\$\@\%\*\&])(.+)/) { + if ($sym =~ /\W/) { + # time for a more-detailed check-up + if ($sym =~ /^\w+[[{].*[]}]$/) { + require Carp; + Carp::croak("Can't declare individual elements of hash or array"); + } elsif (warnings::enabled() and length($sym) == 1 and $sym !~ tr/a-zA-Z//) { + warnings::warn("No need to declare built-in vars"); + } elsif (($^H &= strict::bits('vars'))) { + require Carp; + Carp::croak("'$_' is not a valid variable name under strict vars"); + } + } + $sym = "${callpack}::$sym" unless $sym =~ /::/; + *$sym = + ( $ch eq "\$" ? \$$sym + : $ch eq "\@" ? \@$sym + : $ch eq "\%" ? \%$sym + : $ch eq "\*" ? \*$sym + : $ch eq "\&" ? \&$sym + : do { + require Carp; + Carp::croak("'$_' is not a valid variable name"); + }); + } else { + require Carp; + Carp::croak("'$_' is not a valid variable name"); + } + } +}; + +1; +__END__ + +=head1 NAME + +vars - Perl pragma to predeclare global variable names (obsolete) + +=head1 SYNOPSIS + + use vars qw($frob @mung %seen); + +=head1 DESCRIPTION + +NOTE: For variables in the current package, the functionality provided +by this pragma has been superseded by C<our> declarations, available +in Perl v5.6.0 or later. See L<perlfunc/our>. + +This will predeclare all the variables whose names are +in the list, allowing you to use them under "use strict", and +disabling any typo warnings. + +Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and +C<use subs> declarations are not BLOCK-scoped. They are thus effective +for the entire file in which they appear. You may not rescind such +declarations with C<no vars> or C<no subs>. + +Packages such as the B<AutoLoader> and B<SelfLoader> that delay +loading of subroutines within packages can create problems with +package lexicals defined using C<my()>. While the B<vars> pragma +cannot duplicate the effect of package lexicals (total transparency +outside of the package), it can act as an acceptable substitute by +pre-declaring global symbols, ensuring their availability to the +later-loaded routines. + +See L<perlmodlib/Pragmatic Modules>. + +=cut |