* Darren Chamberlain <d...@sevenroot.org> [2010-09-11 10:05]:
> Template Toolkit (and several other modules) use this idiom:
>
> sub new {
> my $class = shift;
>
> # allow hash ref as first argument, otherwise fold args into hash
> my $config = defined $_[0] && UNIVERSAL::isa($_[0], 'HASH') ? shift : {
> @_ };
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> ..
> }
That’s incredibly horrible. It should at least be using `reftype`
instead of abusing `UNIVERSAL::isa`. But in fact it should be
using just `ref`. You don’t want to reach inside an object just
because it happens to be hash-based. Miyagawa and I struggled
with this in writing Hash::MultiValue and eventually he settled
for this: <http://p3rl.org/Hash::MultiValue#NOTES_ON_ref>.
Perl( 5) just doesn’t really provide semantics for distinguishing
interface from implementation there.
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
