From: "David A. Black" <dblack@...>
Date: 2005-08-26T21:50:45+09:00
Subject: Re: symbols vs. strings

Hi --

On Fri, 26 Aug 2005, Mark Volkmann wrote:

> I got the impression that when a method expects a Hash containing
> certain keys, I can generally specify the keys using either Symbol or
> String objects. So I tried this.
>
> h = {}
> h[:foo] = 19
> h['foo'] = 20
>
> and was surprised to see that those are treated as distinct entries
> in the Hash.
>
> So how is it that I can sometimes choose whether I want to specify a
> given key as either a Symbol or a String?

You can hook into the [] and []= methods.  Here's one way:

module SSHash
   def []=(k,v)
     super(k.to_s,v)
   end

   def [](k)
     super(k.to_s)
   end
end

h = {}.extend(SSHash)

h[:a] = 1
h["b"] = 2
p h["a"]     # 1
p h[:b]      # 2

(Note that redefining [] and []= does not affect other get/set methods,
like fetch.)


David

-- 
David A. Black
dblack@wobblini.net