mop

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

diff --git a/lib/Class/MOP/Attribute.pm b/lib/Class/MOP/Attribute.pm
index fa13bf3..df0fb3c 100644 (file)
--- a/lib/Class/MOP/Attribute.pm
+++ b/lib/Class/MOP/Attribute.pm
@@ -7,7 +7,7 @@ use warnings;
 use Carp         'confess';
 use Scalar::Util 'blessed', 'reftype', 'weaken';
 
-our $VERSION = '0.04';
+our $VERSION = '0.07';
 
 sub meta { 
     require Class::MOP::Class;
@@ -60,6 +60,20 @@ sub clone {
     return bless { %{$self}, %options } => blessed($self);
 }
 
+sub initialize_instance_slot {
+    my ($self, $class, $instance, $params) = @_;
+    my $init_arg = $self->{init_arg};
+    # try to fetch the init arg from the %params ...
+    my $val;        
+    $val = $params->{$init_arg} if exists $params->{$init_arg};
+    # if nothing was in the %params, we can use the 
+    # attribute's default value (if it has one)
+    if (!defined $val && defined $self->{default}) {
+        $val = $self->default($instance); 
+    }            
+    $instance->{$self->name} = $val;    
+}
+
 # NOTE:
 # the next bunch of methods will get bootstrapped 
 # away in the Class::MOP bootstrapping section
@@ -122,7 +136,10 @@ sub generate_accessor_method {
 
 sub generate_reader_method {
     my ($self, $attr_name) = @_; 
-    sub { $_[0]->{$attr_name} };   
+    sub { 
+        confess "Cannot assign a value to a read-only accessor" if @_ > 1;
+        $_[0]->{$attr_name}; 
+    };   
 }
 
 sub generate_writer_method {
@@ -260,8 +277,6 @@ An attribute must (at the very least), have a C<$name>. All other
 C<%options> are contained added as key-value pairs. Acceptable keys
 are as follows:
 
-=item B<clone (%options)>
-
 =over 4
 
 =item I<init_arg>
@@ -372,6 +387,10 @@ defined, and false (C<0>) otherwise.
 
 =back
 
+=item B<clone (%options)>
+
+=item B<initialize_instance_slot ($instance, $params)>
+
 =back 
 
 =head2 Informational