This page describes the process we will follow to replace the current Stream library by Nile, a complete reimplementation based on traits. See http://www.squeaksource.com/Nile.

Cleaning Squeak

• avoid direct references to classes like ReadStream or WriteStream
• Work in progress: replace ReadStream on: expr by expr readStream.

Here is the refactoring to do it:

(ParseTreeRewriter new
    replace: 'ReadStream on: ``@object' with: '``@object readStream';
    yourself)

• Do the same for WriteStream (take care of the two constructors #on: and #with:).
• Do the same for ReadWriteStream.

Adding features to Nile

• Implement InflateStream and the others using NSTDecoder.
• Implements nextChunk and the others in their own class.

Installing Nile

• Nile is available on the Universe and on SqueakSource.

Replacing Squeak streams by Nile

• Start by replacing SequenceableCollection>>readStream to use Nile. Expect things to crash. :-)
• Also, implement !String>>readStream to return an instance of NSStringStream.

Removing the Squeak Stream hierarchy

• This will require changes in a lot of non-Squeak packages. I don't think it will be too hard and just avoiding direct references to ReadStream and WriteStream could be enough.

Changing the semantic of Streams (need discussions)

• Sending errors instead of returning nil (on #next for example). See the ProposalForConsistentStreamsBehavior.