diff -r f196858c983e -r 0fc33e54b1c6 lib/Scalar/LockRefType.pm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Scalar/LockRefType.pm	Tue Jul 29 21:35:01 2014 +0200
@@ -0,0 +1,59 @@
+package Scalar::LockRefType;
+use strict;
+use warnings;
+use Carp;
+
+our $VERSION = '0.02';
+
+sub TIESCALAR {
+    my ($class, $type) = @_;
+    return bless {
+        value => undef,
+        type  => @_ < 2 ? undef
+        : ref($type)    ? ref($type)
+        : length($type) ? $type
+        :                 ''
+    };
+}
+
+sub FETCH { return $_[0]->{value} }
+
+sub STORE {
+    my ($self, $value) = @_;
+    my $ref = ref $value // '';
+    $self->{type} //= $ref;
+    croak 'invalid reference type' if $ref ne $self->{type};
+    return $self->{value} = $value;
+}
+
+__END__
+
+=head1 NAME
+
+ Scalar::LockRefType - simple scalar type checker
+
+=head1 SYNOPSIS
+
+ use Scalar::LockRefType;
+
+ tie my $h1 => 'Scalar::LockRefType', {};
+ tie my $h2 => 'Scalar::LockRefType', 'HASH';
+ tie my $h3 => 'Scalar::LockRefType';
+
+ $h1 = [];  # dies, violates the type
+ $h2 = [];  # dies, violates the type
+
+ $h3 = {};  # sets the type
+ $h3 = [];  # dies
+
+=head1 DESCRIPTION
+
+This little module allows you to tie the type of a scalar to a specified
+reference type. If the refererence type of an assignment violates the 
+tied type, the assignment throws an exception.
+
+=head1 AUTHOR
+
+Heiko Schlittermann <hs@schlittermann.de>
+
+=cut