About PositionableStream class>>on:from:to

Hi,

I do not understand the behavior of #on:from:to:

(ReadStream on: 'abcdefgh' from: 4 to: 7) contents.    ==>  'abcdefg'
  "really strange"
(PositionableStream on: 'abcdefgh' from: 4 to: 7) contents.       ==>
'defg'      "which sounds normal to me"

And PositionableStream is an abstract class whereas ReadStream is concrete.

--
Damien Cassou