File perl-Safe-Isa.spec of Package perl-Safe-Isa

# spec file for package perl-Safe-Isa
# Copyright (c) 2018 SUSE LINUX GmbH, Nuernberg, Germany.
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# upon. The license for this file, and modifications and additions to the
# file, is the same license as for the pristine package itself (unless the
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# Please submit bugfixes or comments via

Name:           perl-Safe-Isa
Version:        1.000010
Release:        0
%define cpan_name Safe-Isa
Summary:        Call isa, can, does and DOES safely on things that may not be objects
License:        Artistic-1.0 OR GPL-1.0-or-later
Group:          Development/Libraries/Perl
Source1:        cpanspec.yml
BuildArch:      noarch
BuildRoot:      %{_tmppath}/%{name}-%{version}-build
BuildRequires:  perl
BuildRequires:  perl-macros

How many times have you found yourself writing:

  if ($obj->isa('Something')) {

and then shortly afterwards cursing and changing it to:

  if (Scalar::Util::blessed($obj) and $obj->isa('Something')) {

Right. That's why this module exists.

Since perl allows us to provide a subroutine reference or a method name to
the -> operator when used as a method call, and a subroutine doesn't
require the invocant to actually be an object, we can create safe versions
of isa, can and friends by using a subroutine reference that only tries to
call the method if it's used on an object. So:

  my $isa_Foo = $maybe_an_object->$_call_if_object(isa => 'Foo');

is equivalent to

  my $isa_Foo = do {
    if (Scalar::Util::blessed($maybe_an_object)) {
    } else {

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
'is_module_name' function from 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.

%setup -q -n %{cpan_name}-%{version}

%{__perl} Makefile.PL INSTALLDIRS=vendor
%{__make} %{?_smp_mflags}

%{__make} test


%files -f %{name}.files
%doc Changes README

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