houston/houston-core

module CoreExt
  module Hash



    def pick(*picks)
      picks = picks.flatten

      mapped_picks = {}
      picks.each do |pick|
        if pick.is_a?(Hash)
          mapped_picks.merge!(pick)
        else
          mapped_picks[pick] = pick
        end
      end

      mapped_picks.inject({}) do |result, (key, new_key)|
        result[new_key] = self[key] if self.key?(key)
        result
      end
    end



    def pick!(*picks)
      picks = picks.flatten
      keys.each {|key| self.delete(key) unless picks.member?(key) }
    end



    def except(*picks)
      result = self.dup
      result.except!(*picks)
      result
    end



    def except!(*picks)
      picks = picks.flatten
      keys.each {|key| self.delete(key) if picks.member?(key) }
    end



  end
end

Hash.send :include, CoreExt::Hash