From: Trans <transfire@...>
Date: 2006-10-25T01:10:10+09:00
Subject: Re: '**' as hash splat?


Ken Bloom wrote:
> On Mon, 23 Oct 2006 20:49:55 -0700, Trans wrote:
>
> > We can:
> >
> >   a = [2,1]
> >   [3,*a]  #=> [3,2,1]
> >
> > How about:
> >
> >   h = {:b=>2, :a=>1}
> >   {:c => 3, **h}  #=> {:c=>3, :b=>2, :a=>1}
> >
> > T.
>
> The purpose of splat is to convert an array into a list of parameters to a
> method. Since [] is a method, this happens to work well for including an
> array into another array. But that's not its purpose, just a side effect.
>
> There's no real concept of converting a hash into a list of parameters to
> a function, so there's no splat notation for it.

Not so for Ruby 2.0, assuming we do indeed get key parameters:

  def foo( **keys )
    p keys
  end

> If you want to combine hashes, use the merge method
>
> {:c=>3}.merge(h) #=> {:a=>1, :b=>2, :c=>3}

And with arrays one can use #+. That's fine, but it lacks a certain
elegance in some instances.
T.