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Postings from October 2016
On Thu, 6 Oct 2016 05:59:28 +0100
Sam Kington <sam@illuminated.co.uk> wrote:
> The other one is similar: it’s about optional elements of hashes.
> It’s the sort of thing where you end up writing;
>
> optional(
> thing => $thing,
> (exists $params{this} ? this => $params{this} : ()),
> (exists $params{that} ? that => $params{that} : ()),
> );
>
> until you get fed up and you refactor it as
>
> my %optional_params = (thing => $thing);
> for (qw(this that)) {
> $optional_params{$_} = $params{$_} if $params{$_};
> }
> optional(%optional_params);
>
> but who are you fooling? It’s still nasty. The fact that you used $_
> doesn’t hide the fact that you repeated the name of the variable all
> over the place, or that you needed a custom loop.
>
> I wonder if you could do something interesting with the fat comma?
>
> For instance:
>
> mandatory(
> thing => $thing,
> this =>! this_does_something(),
> that =>! that_does_something(),
> );
>
> and
>
> optional(
> thing => $thing,
> this =>? $params{this},
> that =>? $params{that},
> );
That's what hash slices are for
optional(
thing => $thing,
%{$params}{qw( this that )}
)
--
Paul "LeoNerd" Evans
leonerd@leonerd.org.uk | https://metacpan.org/author/PEVANS
http://www.leonerd.org.uk/ | https://www.tindie.com/stores/leonerd/
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