add contains method to MethodProvider/List

[gitmo/MooseX-AttributeHelpers.git] / lib / MooseX / AttributeHelpers / MethodProvider / List.pm

diff --git a/lib/MooseX/AttributeHelpers/MethodProvider/List.pm b/lib/MooseX/AttributeHelpers/MethodProvider/List.pm
index 95648cc..154d39b 100644 (file)
--- a/lib/MooseX/AttributeHelpers/MethodProvider/List.pm
+++ b/lib/MooseX/AttributeHelpers/MethodProvider/List.pm
@@ -54,6 +54,17 @@ sub elements : method {
     };
 }
 
+sub contains : method {
+    my ($attr, $reader, $writer) = @_;
+    return sub {
+        my ($instance, $item) = @_;
+        return scalar (defined $item ?
+            CORE::grep {defined && $_ eq $item} @{$reader->($instance)}
+            : CORE::grep {!defined} @{$reader->($instance)}
+        );
+    };
+}
+
 sub join : method {
     my ($attr, $reader, $writer) = @_;
     return sub {
@@ -106,15 +117,16 @@ MooseX::AttributeHelpers::MethodProvider::List
       default    => sub { [] },
       auto_deref => 1,
       provides   => {
-         map   => 'map_options',
-         grep  => 'filter_options',
-         find  => 'find_option',
-         first => 'first_option',
-         last  => 'last_option',
-         get   => 'get_option',
-         join  => 'join_options',
-         count => 'count_options',
-         empty => 'do_i_have_options',
+         map      => 'map_options',
+         grep     => 'filter_options',
+         find     => 'find_option',
+         first    => 'first_option',
+         last     => 'last_option',
+         get      => 'get_option',
+         join     =>  'join_options',
+         count    => 'count_options',
+         empty    => 'do_i_have_options',
+         contains => 'options_contains',
 
       }
    );
@@ -180,6 +192,16 @@ Returns an element of the list by its index.
    my $option = $stuff->get_option(1);
    print "$option\n"; # prints "bar"
 
+=item B<contains>
+Returns a true value if the list contains the passed value, otherwise returns
+a false value. The return value is actually the number of times the passed
+value appears in the list (0, or more).
+
+   my $found = $stuff->contains( 'apple' );
+   print "Found apple in the list\n" if $found;
+
+Note that this works even when looking for the undefined value.
+
 =item B<join>
 Joins every element of the list using the separator given as argument.