skip the redundant blessed call in $_call_if_can

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

diff --git a/lib/Safe/Isa.pm b/lib/Safe/Isa.pm
index d13d01e..e7a1337 100644 (file)
--- a/lib/Safe/Isa.pm
+++ b/lib/Safe/Isa.pm
@@ -2,16 +2,20 @@ package Safe::Isa;
 
 use strict;
 use warnings FATAL => 'all';
-use Scalar::Util qw(blessed);
-use base qw(Exporter);
+use Scalar::Util ();
+use Exporter 5.57 qw(import);
 
-our $VERSION = '1.000000';
+our $VERSION = '1.000007';
 
-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, $method) = (shift, shift);
-  return unless blessed($obj);
+  # This is intentionally a truth test, not a defined test, otherwise
+  # we gratuitously break modules like Scalar::Defer, which would be
+  # un-perlish.
+  return unless Scalar::Util::blessed($obj);
+  return $obj->isa(@_) if lc($method) eq 'does' and not $obj->can($method);
   return $obj->$method(@_);
 };
 
@@ -20,6 +24,16 @@ 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) && $obj->$method(@_);
+};
+
+1;
+__END__
+
+=pod
+
 =head1 NAME
 
 Safe::Isa - Call isa, can, does and DOES safely on things that may not be objects
@@ -63,9 +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:
 
@@ -103,6 +118,11 @@ is equivalent to
     }
   };
 
+Note that we don't handle trying class names, because many things are valid
+class names that you might not want to treat as one (like say "Matt") - the
+C<is_module_name> function from L<Module::Runtime> is a good way to check for
+something you might be able to call methods on if you want to do that.
+
 =head1 EXPORTS
 
 =head2 $_isa
@@ -133,13 +153,26 @@ returns nothing.
 If called on an object, calls C<DOES> on it and returns the result, otherwise
 returns nothing.
 
-=head2 $_call_if_method
+=head2 $_call_if_object
 
-  $maybe_an_object->$_call_if_method(method_name => @args);
+  $maybe_an_object->$_call_if_object(method_name => @args);
 
 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
+L<YAPC::NA 2013|https://www.youtube.com/watch?v=wFXWV2yY7gE&t=46m05s>.
+
 =head1 AUTHOR
 
 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>