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Here’s a fun snippet cooked up for the Camping 1.3 release due later today, laid out a bit nicer so you can play with it on your own.

Goal is: to parse a query string in as few bytes as possible. And to allow the Hash-like syntax from PHP and Rails.

 def qs_parse(qs)
   qs.split(/[&;]/n).
      inject({}) { |h,p| 
        k, v = p.split('=',2)
        h.merge(
          k.split(/[\]\[]+/).reverse.
            inject(v) { |x,i| {i=>x} }
        ){|_,o,n|o.merge(n)}
      }
 end

Believe me, there’s a real zen in the inner-inject/merge-block routine. Wield it like so:

 >> qs_parse("name=Philarp+Tremain&hair=sandy+blonde")
 => {"name"=>"Philarp+Tremain", "hair"=>"sandy+blonde"}
 >> qs_parse("post[id]=4&post[nick]=_why&post[message]=GROSS!&a=1")
 => {"a"=>"1", "post"=>{"message"=>"GROSS!", "nick"=>"_why", "id"=>"4"}}

Obviously, in the final version, stuff gets unescaped and all that. This exercise only focuses on parsing the structure. It would be nice for the merge-block to be tail recursive. It only goes one level presently.