From: Joel VanderWerf <vjoel@...>
Date: 2002-12-23T08:58:49+09:00
Subject: Re: Hash#update

Gavin Sinclair wrote:
> I think
> 
>    hash1 | hash2
> 
> would be good.  It tends to communicate nondestructiveness.

That's especially good if you're using hashes as "characteristic 
functions" of sets, in which case this '|' is union:

class Hash
   def |(h)
     dup.update(h)
   end
end

elves = {'Legolas' => true, 'Galadriel' => true}

reindeer = {'Dasher' => true, 'Dancer' => true,
             'Prancer' => true, 'Vixen' => true,
             'Donner' => true, 'Comet' => true,
             'Cupid' => true, 'Blitzen' => true,
             'Rudolph' => true, 'Olive' => true}

p (elves | reindeer)['Comet']            # ==> true
p (elves['Comet'] | reindeer['Comet'])   # ==> true


Eagerly eyeing the ruby-shaped package under tree,
   Joel