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 = '1.000001';
+our $VERSION = '1.000009';
-our @EXPORT = qw($_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
$maybe_an_object->$_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:
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
-somthing you might be able to call methods on if you want to do that.
+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
$maybe_an_object->$_does('Foo');
If called on an object, calls C<does> on it and returns the result, otherwise
-returns nothing.
+returns nothing. If the C<does> method does not exist, returns nothing rather
+than failing.
=head2 $_DOES
$maybe_an_object->$_DOES('Foo');
If called on an object, calls C<DOES> on it and returns the result, otherwise
-returns nothing.
+returns nothing. On perl versions prior to 5.10.0, the built in core C<DOES>
+method doesn't exist. If the method doesn't exist, this will fall back to
+calling C<isa> just like the core C<DOES> method.
=head2 $_call_if_object
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>