—package
vars;
use
5.006;
our
$VERSION
=
'1.05'
;
use
warnings::register;
sub
import
{
my
$callpack
=
caller
;
my
(
undef
,
@imports
) =
@_
;
my
(
$sym
,
$ch
);
foreach
(
@imports
) {
if
((
$ch
,
$sym
) = /^([\$\@\%\*\&])(.+)/) {
if
(
$sym
=~ /\W/) {
# time for a more-detailed check-up
if
(
$sym
=~ /^\w+[[{].*[]}]$/) {
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'
))) {
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
{
Carp::croak(
"'$_' is not a valid variable name"
);
});
}
else
{
Carp::croak(
"'$_' is not a valid variable name"
);
}
}
};
1;
__END__
=head1 NAME
vars - Perl pragma to predeclare global variable names
=head1 SYNOPSIS
use vars qw($frob @mung %seen);
=head1 DESCRIPTION
NOTE: For use with variables in the current package for a single scope, the
functionality provided by this pragma has been superseded by C<our>
declarations, available in Perl v5.6.0 or later, and use of this pragma is
discouraged. See L<perlfunc/our>.
This pragma will predeclare all the variables whose names are
in the list, allowing you to use them under C<use strict>, and
disabling any typo warnings for them.
Unlike pragmas that affect the C<$^H> hints variable, the C<use vars> and
C<use subs> declarations are not lexically scoped to the block they appear
in: they affect
the entire package in which they appear. It is not possible to rescind these
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