From: Magnus Holm <judofyr@...>
Date: 2009-10-27T07:28:46+09:00
Subject: [ruby-core:26341] Suggestion: #from_array

I just got a little idea five minutes ago while I was showering:

In 1.8 we have the annoying "problem" that { }.map/select/reject/sort
returns an Array. This has been fixed in 1.9, but if you have your own
class which includes Enumerable, they will still return an Array.
Basically you have two options:

1) Nothing at all, and let them return arrays
2) Overload them to make them return your class

So I was thinking, what if map was implemented like this:

def map
  new_object = self.class.new
  each { new_object.from_array(*yield) }
  new_object
end

Then every class could simply implement #from_array:

class Hash
  def from_array(key, value)
    self[key] = value
  end
end

Of course, it would have to check if the class has defined
#from_array, if not it would default back to the current behaviour.


What do you think? Something I'm missing; is there another way to
solve this problem?


//Magnus Holm