minor improvements, especially fixing default hashguts key generation

Changes

@@ -1,5 +1,8 @@
 Changelog for Mixin-ExtraFields
 
+0.003    2006-12-11
+         improve uniqueness of default HashGuts key
+
 0.002    2006-12-10
          some documentation improvements
 

lib/Mixin/ExtraFields.pm

@@ -11,13 +11,13 @@ Mixin::ExtraFields - add extra stashes of data to your objects
 
 =head1 VERSION
 
-version 0.002
+version 0.003
 
  $Id$
 
 =cut
 
-our $VERSION = '0.002';
+our $VERSION = '0.003';
 
 =head1 SYNOPSIS
 
@@ -417,10 +417,6 @@ available under the same terms as perl itself.
 
 =item * handle invocants without ids (classes) and drivers that don't need ids
 
-=item * a CGI->param-like subclass, to replace Mixin::Params, never released
-
-=item * a Data::Hive-like subclass -- implemented, but too Listbox-specific
-
 =back
 
 =cut

lib/Mixin/ExtraFields/Driver/HashGuts.pm

@@ -11,13 +11,13 @@ Mixin::ExtraFields::Driver::HashGuts - store extras in a hashy object's guts
 
 =head1 VERSION
 
-version 0.001
+version 0.003
 
  $Id$
 
 =cut
 
-our $VERSION = '0.001';
+our $VERSION = '0.003';
 
 =head1 SYNOPSIS
 
@@ -29,8 +29,9 @@ our $VERSION = '0.001';
 
 This driver class implements an extremely simple storage mechanism: extras are
 stored on the object on which the mixed-in methods are called.  By default,
-they are stored in the key C<__extras>, but this can be changed by providing a
-C<hash_key> argument to the driver configuration, like so:
+they are stored under the key returned by the C<L</default_has_key>> method,
+but this can be changed by providing a C<hash_key> argument to the driver
+configuration, like so:
 
   use Mixin::ExtraFields -fields => {
     driver => { class => 'HashGuts', hash_key => "\0Something\0Wicked\0" }
@@ -49,19 +50,33 @@ This method returns the key where the driver will store its extras.
 
 =cut
 
+sub hash_key {
+  my ($self) = @_;
+  return $self->{hash_key};
+}
+
+=head2 default_hash_key
+
+If no C<hash_key> argument is given for the driver, this method is called
+during driver initialization.  It will return a unique string to be used as the
+hash key.
+
+=cut
+
+my $i = 0;
+sub default_hash_key {
+  my ($self) = @_;
+  return "$self" . '@' . $i++;
+}
+
 sub from_args {
   my ($class, $arg) = @_;
 
-  my $self = {
-    hash_key => $arg->{hash_key} || '__extras',
-  };
+  my $self = bless {} => $class;
 
-  bless $self => $class;
-}
+  $self->{hash_key} = $arg->{hash_key} || $self->default_hash_key;
 
-sub hash_key {
-  my ($self) = @_;
-  return $self->{hash_key};
+  return $self;
 }
 
 sub exists_extra {

t/basic.t

@@ -1,7 +1,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 19;
+use Test::More tests => 20;
 
 BEGIN { require_ok('Mixin::ExtraFields'); }
 
@@ -64,3 +64,6 @@ is_deeply(
   [ datum => { value => 20 } ],
   "get_all_detailed_misc gets the one pair that it should",
 );
+
+eval { (ref $object)->get_all_misc };
+like($@, qr/couldn't determine id/, "exception thrown if called on class");

t/lib/Object/HasExtraFields.pm

@@ -18,7 +18,6 @@ sub new {
 }
 
 sub id {
-  Carp::croak "not given an object" unless ref $_[0];
   0 + $_[0];
 }