X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FSafe%2FIsa.pm;h=fb3c5ab72a2764a22e091541d9cb833b9084d254;hb=9d3d6b490907e28992f225d4527a0460acb3c1d2;hp=b725f214c3b4a41cef78b8efdc08e1967e69c2b5;hpb=e6995dc62a0d32013c0e8722f98cca789520fce1;p=p5sagit%2FSafe-Isa.git

diff --git a/lib/Safe/Isa.pm b/lib/Safe/Isa.pm
index b725f21..fb3c5ab 100644
--- a/lib/Safe/Isa.pm
+++ b/lib/Safe/Isa.pm
@@ -2,23 +2,50 @@ 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 = '1.000008';
 
-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 $obj->$method(@_);
 };
 
-our ($_isa, $_can, $_does, $_DOES) = map {
+our ($_isa, $_can) = map {
   my $method = $_;
   sub { my $obj = shift; $obj->$_call_if_object($method => @_) }
-} qw(isa can does DOES);
+} qw(isa can);
+
+our $_call_if_can = sub {
+  my ($obj, $method) = (shift, shift);
+  return unless $obj->$_call_if_object(can => $method);
+  return $obj->$method(@_);
+};
+
+our $_does = sub {
+  my $obj = shift;
+  $obj->$_call_if_can(does => @_);
+};
+
+our $_DOES = sub {
+  my $obj = shift;
+  return unless Scalar::Util::blessed($obj);
+  return $obj->DOES(@_)
+    if $obj->can('DOES');
+  return $obj->isa(@_);
+};
+
+1;
+__END__
+
+=pod
 
 =head1 NAME
 
@@ -63,15 +90,16 @@ 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:
 
-  $foo->$_call_if_method(isa => 'Foo');  # true
-  $bar->$_call_if_method(isa => 'Foo');  # true
-  $blam->$_call_if_method(isa => 'Foo'); # false, no boom today
+  $foo->$_call_if_object(isa => 'Foo');  # true
+  $bar->$_call_if_object(isa => 'Foo');  # true
+  $blam->$_call_if_object(isa => 'Foo'); # false, no boom today
 
 =head1 DESCRIPTION
 
@@ -103,6 +131,14 @@ 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.
+
+We are careful to make sure that scalar/list context is preserved for the
+method that is eventually called.
+
 =head1 EXPORTS
 
 =head2 $_isa
@@ -133,13 +169,26 @@ 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>