[Edu-sig] xturtle - new version

[Gregor Lingl]

Hi everyone ...

I've been off line for a while, due to a lot of work ...
... but since approx. two weeks I've found time to continue my work
on xturtle.py and to implement a few hopfully useful features as well
as some example scripts demonstrating them. Only one of them I'd
like to mention here, because it proved really very useful for interactive
work with turtle graphics: an undo() method/function, which serves to
correct painlessly the consequences of wrong ideas ;-) 

Notes on the new features are in a text file in the xturtle package as well
as here:

http://www.rg16.at/~python/xturtle/whatsnew.txt

You can download the zipped package with xturtle.py, a demoviewer
and the sample scripts  from the (still not substantially refreshed) 
website:

http://www.rg16.at/~python/xturtle/download.html

Quite a few users asked and/or encouraged me during the last months
to anew propose xturtle.py as a replacement or a supplement for xturtle.py
either for Python 2.6 and especially for Python 3000. (A port of xturtle.py
to Python3000 is under way and nearly ready!)

Morover there is the following point in PEP-0361, the
Python 2.6 and 3.0 release schedule:

- turtle.py replacement or enhancements

I'll propose my workto the developer community within a short time.
The code of the current version works well,  albeit it certainly still has
some bugs. (I hope to get bug reports form users ....) 
I plan to polish the code during the next weeks.

For now I think, that the current version can serve well as a basis for
a discussion about the following topics:

1) about the API - i. e. about the naming of the classes and methods
as well as about the question if there are some which could be eliminated
or other new features which should be added. (Imho I've reached a
point where it seems not to be reasonable to add substantially more 
features)

2) about the question if xturtle should be compatible to turtle.py as far
as possible, in the sense that turtle-programs should run with xturtle
in the same way. (I think this is to a far extent the case now - but it
complicates and extends the code of xturtle considerably.)

Of course many users as well as nonusers of turtle graphics have a
lot of different opinions about it's advantages and disadvantages.I'd
just like to mention once more, the for me it is a very valuable instrument
to visualize computer science concepts easily and consequently to
teach programming. To see better what I mean with this, please have a look
at the code of the minimal_hanoi.py sample script, which implements a
graphical animation of the tower of hanoi game using a lot of advanced
concepts of Python but nearly without any overhead for graphics operations.
That's just my approach to using turtle graphics.

So I'd like to modestly ask you to have a look at the xturtle package,
think about it's usefulness for educational purposes and give some
feedback or contribute otherwise to the discussion.

With kind regards,
Gregor