[Cuis] Ropes (functional strings)

[Ken Dickey]

Juan wrote:

> Yesterday I played a bit to see how quickly the system would break if 
> #at: and #at:put: were banned for Strings.

I did a simple, prototype implementation of Ropes, functional strings, for Cuis.

Ropes are _immutable_ (constant) strings, and #at:put: returns a new Rope.  Internal data structures hide the details.

The basic idea is that I had a utf-8 Rope and #at:put: a utf-32 Chinese character into it, then we would NOT have to change the utf-8 part just because of one character.  We could have separate 8/16/32 bit char-arrays supporting Unicode and do mix 'n match as we needed.

	https://github.com/KenDickey/Cuis-Ropes

Invoking 
	Rope openTextEditor
brings up a simple text editor with a rope instead of a string.

This seems to work OK for me, but more knowledgeable people should take a look.

As this is a prototype, Rope>>doesNotUnderstand writes a message to the Transcript and re-sends it to its stringRepresentation.

So far, I have only seen sends to #encompassParagraph, which I don't yet understand and did not implement.

Anyway, feel free to take a look and let me know if you think it is useful.

Cheers,
-KenD