X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FSafe%2FIsa.pm;h=fb3c5ab72a2764a22e091541d9cb833b9084d254;hb=9d3d6b490907e28992f225d4527a0460acb3c1d2;hp=81d228160089f5d616fe3f7e3b2e35bf3ad28dc4;hpb=f3335392f5835f3396cccd906b7716ce02bb06c0;p=p5sagit%2FSafe-Isa.git

diff --git a/lib/Safe/Isa.pm b/lib/Safe/Isa.pm
index 81d2281..fb3c5ab 100644
--- a/lib/Safe/Isa.pm
+++ b/lib/Safe/Isa.pm
@@ -2,26 +2,50 @@ package Safe::Isa;
 
 use strict;
 use warnings FATAL => 'all';
-use Scalar::Util qw(blessed);
+use Scalar::Util ();
 use Exporter 5.57 qw(import);
 
-our $VERSION = '1.000005';
+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, $method) = (shift, shift);
   # This is intentionally a truth test, not a defined test, otherwise
   # we gratuitously break modules like Scalar::Defer, which would be
   # un-perlish.
-  return unless blessed($obj);
+  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
 
@@ -66,9 +90,10 @@ 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:
 
@@ -111,6 +136,9 @@ 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
@@ -148,6 +176,19 @@ 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
+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>