From: Trans <transfire@...>
Date: 2008-10-28T10:38:57+09:00
Subject: Re: Hash.merge_add! extension - how does this code look?



On Oct 27, 8:42 pm, "Greg Hauptmann" <greg.hauptmann.r...@gmail.com>
wrote:
> thanks all for feedback to date - here's my latest take
>
> ------------------------------------
>   def merge_add!(h)
>     raise "Parameter passed in not a hash" if !h.instance_of?(Hash)

Again, this is considered poor form. The reason is, if it isn't a Hash
it will blow up in the next couple of statements anyway, but more
importantly something other a Hash might emulate one. And there's no
reason not to allow it to work.

>     # normalise input hash to contain arrays
>     h.each { |key, value| if !value.instance_of?(Array) then h[key] =
> [value] end }
>
>     self.merge!(h) do |key, existing, new|
>       existing = existing.instance_of?(Array) ? existing : [existing]
>       existing + new
>     end
>   end


  def merge_add!(h)
    q = {}
    (keys | h.keys).each do |k|
      q[k] = Array(self[k]) + Array(h[k])
    end
    replace(q)
  end


                              trans.