adding to changelog and changing versions

[gitmo/Class-MOP.git] / lib / Class / MOP / Attribute.pm

diff --git a/lib/Class/MOP/Attribute.pm b/lib/Class/MOP/Attribute.pm
index 1b721d7..8173a67 100644 (file)
--- a/lib/Class/MOP/Attribute.pm
+++ b/lib/Class/MOP/Attribute.pm
@@ -9,7 +9,7 @@ use Class::MOP::Method::Accessor;
 use Carp         'confess';
 use Scalar::Util 'blessed', 'reftype', 'weaken';
 
-our $VERSION   = '0.20';
+our $VERSION   = '0.23';
 our $AUTHORITY = 'cpan:STEVAN';
 
 use base 'Class::MOP::Object';
@@ -49,10 +49,16 @@ sub new {
                        "wrap then in a CODE reference (ex: sub { [] } and not [])")
                 if exists $options{default} && ref $options{default};
     }
+    if( $options{required} and not( defined($options{builder}) || defined($options{init_arg}) || exists $options{default} ) ) {
+        confess("A required attribute must have either 'init_arg', 'builder', or 'default'");
+    }
     bless {
         '$!name'      => $name,
         '$!accessor'  => $options{accessor},
         '$!reader'    => $options{reader},
+        # NOTE:
+        # protect this from silliness
+        init_arg => '!............( DO NOT DO THIS )............!',
         '$!writer'    => $options{writer},
         '$!predicate' => $options{predicate},
         '$!clearer'   => $options{clearer},
@@ -88,7 +94,7 @@ sub initialize_instance_slot {
 
     # if nothing was in the %params, we can use the
     # attribute's default value (if it has one)
-    if(exists $params->{$init_arg}){
+    if(defined $init_arg and exists $params->{$init_arg}){
         $meta_instance->set_slot_value($instance, $self->name, $params->{$init_arg});
     } 
     elsif (defined $self->{'$!default'}) {
@@ -398,12 +404,6 @@ value of C<-foo>, then the following code will Just Work.
 In an init_arg is not assigned, it will automatically use the
 value of C<$name>.
 
-=item I<default>
-
-The value of this key is the default value which
-C<Class::MOP::Class::construct_instance> will initialize the
-attribute to.
-
 =item I<builder>
 
 The value of this key is the name of the method that will be
@@ -411,6 +411,12 @@ called to obtain the value used to initialize the attribute.
 This should be a method in the class associated with the attribute,
 not a method in the attribute class itself.
 
+=item I<default>
+
+The value of this key is the default value which
+C<Class::MOP::Class::construct_instance> will initialize the
+attribute to.
+
 B<NOTE:>
 If the value is a simple scalar (string or number), then it can
 be just passed as is. However, if you wish to initialize it with
@@ -495,9 +501,19 @@ C<undef> value to the attribute.
 
 =item I<predicate>
 
-This is a basic test to see if the value of the attribute is not
-C<undef>. It will return true (C<1>) if the attribute's value is
-defined, and false (C<0>) otherwise.
+This is a basic test to see if any value has been set for the 
+attribute. It will return true (C<1>) if the attribute has been set 
+to any value (even C<undef>), and false (C<0>) otherwise.
+
+B<NOTE:>
+The predicate will return true even when you set an attribute's
+value to C<undef>. This behaviour has changed as of version 0.43. In 
+older versions, the predicate (erroneously) checked for attribute 
+value definedness, instead of presence as it is now.
+
+If you really want to get rid of the value, you have to define and 
+use a I<clearer> (see below).
+
 
 =item I<clearer>
 
@@ -534,7 +550,7 @@ even to attributes with just write only accessors.
 
 =item B<has_value ($instance)>
 
-Returns a boolean indicating if the item in the C<$instance> has a value in it.
+Return a boolean indicating if the item in the C<$instance> has a value in it.
 This is basically what the default C<predicate> method calls.
 
 =item B<clear_value ($instance)>
@@ -570,13 +586,15 @@ passed into C<new>. I think they are pretty much self-explanitory.
 
 =item B<default (?$instance)>
 
-As noted in the documentation for C<new> above, if the I<default>
-value is a CODE reference, this accessor will pass a single additional
-argument C<$instance> into it and return the value.
+Return the default value for the attribute.
+
+If you pass in an C<$instance> argument to this accessor and the
+I<default> is a CODE reference, then the CODE reference will be
+executed with the C<$instance> as its argument.
 
 =item B<slots>
 
-Returns a list of slots required by the attribute. This is usually
+Return a list of slots required by the attribute. This is usually
 just one, which is the name of the attribute.
 
 =item B<get_read_method>
@@ -724,7 +742,7 @@ Stevan Little E<lt>stevan@iinteractive.comE<gt>
 
 =head1 COPYRIGHT AND LICENSE
 
-Copyright 2006, 2007 by Infinity Interactive, Inc.
+Copyright 2006-2008 by Infinity Interactive, Inc.
 
 L<http://www.iinteractive.com>