1 files changed, 33 insertions, 0 deletions
diff --git a/lib/Class/Fields.pm b/lib/Class/Fields.pm
new file mode 100644
index 0000000000..4b23e7d731
--- /dev/null
+++ b/lib/Class/Fields.pm
@@ -0,0 +1,33 @@
+package Class::Fields;
+use Carp;
+
+sub import {
+    my $class = shift;
+    my ($package) = caller;
+    my $fields = \%{"$package\::FIELDS"};
+    my $i = $fields->{__MAX__};
+    foreach my $f (@_) {
+	if (defined($fields->{$f})) {
+	    croak "Field name $f already used by a base class"
+	}
+	$fields->{$f} = ++$i;
+    }
+    $fields->{__MAX__} = $i;
+    push(@{"$package\::ISA"}, "Class::Fields");
+}
+
+sub new {
+    my $class = shift;
+    bless [\%{"$class\::FIELDS"}, @_], $class;
+}
+
+sub ISA {
+    my ($class, $package) = @_;
+    my $from_fields = \%{"$class\::FIELDS"};
+    my $to_fields = \%{"$package\::FIELDS"};
+    return unless defined %$from_fields;
+    croak "Ambiguous inheritance for %FIELDS" if defined %$to_fields;
+    %$to_fields = %$from_fields;
+}
+
+1;