$_call_if_can

[p5sagit/Safe-Isa.git] / lib / Safe / Isa.pm

diff --git a/lib/Safe/Isa.pm b/lib/Safe/Isa.pm
index 2f4f357..2e29b3c 100644 (file)
--- a/lib/Safe/Isa.pm
+++ b/lib/Safe/Isa.pm
@@ -7,7 +7,7 @@ use Exporter 5.57 qw(import);
 
 our $VERSION = '1.000006';
 
-our @EXPORT = qw($_call_if_object $_isa $_can $_does $_DOES);
+our @EXPORT = qw($_call_if_object $_isa $_can $_does $_DOES $_call_if_can);
 
 our $_call_if_object = sub {
   my ($obj, $method) = (shift, shift);
@@ -24,6 +24,11 @@ our ($_isa, $_can, $_does, $_DOES) = map {
   sub { my $obj = shift; $obj->$_call_if_object($method => @_) }
 } qw(isa can does DOES);
 
+our $_call_if_can = sub {
+  my ($obj, $method) = (shift, shift);
+  $obj->$_call_if_object(can => $method) && $obj->$_call_if_object($method => @_);
+};
+
 1;
 __END__
 
@@ -72,9 +77,10 @@ Similarly:
   $maybe_an_object->$_does('RoleName'); # true or false, no boom today
   $maybe_an_object->$_DOES('RoleName'); # true or false, no boom today
 
-And just in case we missed a method:
+And just in case we missed a method or two:
 
   $maybe_an_object->$_call_if_object(name => @args);
+  $maybe_an_object->$_call_if_can(name => @args);
 
 Or to re-use a previous example for purposes of explication:
 
@@ -154,6 +160,14 @@ returns nothing.
 If called on an object, calls C<method_name> on it and returns the result,
 otherwise returns nothing.
 
+=head2 $_call_if_can
+
+  $maybe_an_object->$_call_if_can(name => @args);
+
+If called on an object, calls C<can> on it; if that returns true, then
+calls C<method_name> on it and returns the result; if any condition is false
+returns nothing.
+
 =head1 SEE ALSO
 
 I gave a lightning talk on this module (and L<curry> and L<Import::Into>) at