What is the best practice for finding all the superclasses of a Perl class?
Most likely these days you want to use one of the functions from mro
, such as mro::get_linear_isa
.
use mro;
my @superclasses = mro::get_linear_isa($class);
There is no "standard way" because this is not a standard thing you want to do. For anything other than visualization it is an OO red flag to want to inspect your inheritance tree.
In addition to Class::ISA, there is mro::get_linear_isa(). Both have been in core for a while so they could be considered "standard" for some definition. Both of those show inheritance as a flat list, not a tree, which is useful mostly for deep magic.
The perl5i meta object provides both linear_isa(), like mro (it just calls mro), and ISA() which returns the class' @ISA
. It can be used to construct a tree using simple recursion without getting into symbol tables.
use perl5i::2;
func print_isa_tree($class, $depth) {
$depth ||= 0;
my $indent = " " x $depth;
say $indent, $class;
for my $super_class ($class->mc->ISA) {
print_isa_tree($super_class, $depth+1);
}
return;
}
my $Class = shift;
$Class->require;
print_isa_tree($Class);
__END__
DBIx::Class
DBIx::Class::Componentised
Class::C3::Componentised
DBIx::Class::AccessorGroup
Class::Accessor::Grouped
I think Class::ISA is something like you are looking for
use Class::ISA;
use Mojolicious;
print join "\n", Class::ISA::super_path("Mojolicious");
Prints:
Mojo
Mojo::Base
However, it's not some kind of "best practice" since the whole task isn't something Perl programmers do every day.