I sometimes outsmart myself.

[perl5.git] / lib / vars.pm

diff --git a/lib/vars.pm b/lib/vars.pm
index 0dd5758..a051ba1 100644 (file)
--- a/lib/vars.pm
+++ b/lib/vars.pm
@@ -1,8 +1,49 @@
 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, $ch);
+    foreach (@imports) {
+        ($ch, $sym) = unpack('a1a*', $_);
+       if ($sym =~ tr/A-Za-z_0-9//c) {
+           # 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  ( $^H &= strict::bits('vars') ) {
+              Carp::croak("'$_' 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");
+            });
+    }
+};
+
+1;
+__END__
+
 =head1 NAME
 
-vars - Perl pragma to predeclare global variable names
+vars - Perl pragma to predeclare global variable names (obsolete)
 
 =head1 SYNOPSIS
 
@@ -10,37 +51,27 @@ vars - Perl pragma to predeclare global variable names
 
 =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+by this pragma has been superseded by C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.
 
-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 to the later-loaded routines.
+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>.
 
-See L<perlmod/Pragmatic Modules>.
+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.
 
-=cut
-require 5.000;
-use Carp;
+See L<perlmodlib/Pragmatic Modules>.
 
-sub import {
-    my $callpack = caller;
-    my ($pack, @imports, $sym, $ch) = @_;
-    foreach $sym (@imports) {
-       croak "Can't declare another package's variables" if $sym =~ /::/;
-        ($ch, $sym) = unpack('a1a*', $sym);
-        *{"${callpack}::$sym"} =
-          (  $ch eq "\$" ? \$   {"${callpack}::$sym"}
-           : $ch eq "\@" ? \@   {"${callpack}::$sym"}
-           : $ch eq "\%" ? \%   {"${callpack}::$sym"}
-           : $ch eq "\*" ? \*   {"${callpack}::$sym"}
-           : $ch eq "\&" ? \&   {"${callpack}::$sym"}
-           : croak "'$ch$sym' is not a valid variable name\n");
-    }
-};
-
-1;
+=cut