[Python-Dev] xturtle.py a replacement for turtle.py(!?) ATTENTION PLEASE!

[Gregor Lingl]

Martin v. Löwis schrieb:
> Collin Winter wrote:
>   
>> While I have no opinion on Gregor's app, and while I fully agree that
>> new language features and stdlib modules should generally stay out of
>> bug-fix point releases, xturtle doesn't seem to rise to that level
>> (and hence, those restrictions).
>>     
>
> It's a stdlib module, even if no other stdlib modules depend on it;
> try "import turtle".
>
> In the specific case, the problem with adding it to 2.5 is that xturtle
> is a huge rewrite, so ideally, the code should be reviewed before being
> added. Given that this is a lot of code, nobody will have the time to
> perform a serious review. It will be hard enough to find somebody to
> review it for 2.6 - often, changes of this size take several years to
> review (primarily because it is so specialized that only few people
> even consider reviewing it).
>   
Sorry Martin, but to me this seems not to be the right way to manage things.
We have turtle.py revised in Python2.5b1

Please try this example (as I  just did) :

IDLE 1.2b1      ==== No Subprocess ====
 >>> from turtle import *
 >>> begin_fill()
 >>> circle(100,90)  # observe the turtle
 >>> backward(200)
 >>> circle(100,90)
 >>> color("red")
 >>> end_fill()
IDLE internal error in runcode()
Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    end_fill()
  File "C:\Python25\lib\lib-tk\turtle.py", line 724, in end_fill
    def end_fill(): _getpen.end_fill()
AttributeError: 'function' object has no attribute 'end_fill'
 >>>

An error occurs, because in line 724 it should read
def end_fill(): _getpen().end_fill()

(Who reviewed it? This is a _newly_added_ function -
did nobody try it out yet? Incredible!!)

I corrected it and did:

IDLE 1.2b1      ==== No Subprocess ====
 >>> from turtle import *
 >>> begin_fill()
 >>> circle(100,90)
 >>> backward(200)
 >>> circle(100,90)
 >>> color("red")
 >>> end_fill()
 >>>

What a shame!! An immanent bug, persistent
for years now!

Is this what Anthony Baxter calls
"the most solid Python release ever"

In contrast to this:

IDLE 1.2b1      ==== No Subprocess ====
 >>> from xturtle import *
 >>> begin_fill()
 >>> circle(100,90)
 >>> backward(200)
 >>> circle(100,90)
 >>> color("red")
 >>> end_fill()
 >>>

works correctly and the turtle travels along the arcs
with the same speed as along the straight lines.
Bugs like the one I detected above (by chance) cannot occur in the code of
my xturtle, because I don't have to type the definitions of those 
frunctions
into the script by hand. Instead they are generated automatically from the
corresponding methods of RawPen and Pen respectively.

And aren't 25+ bugfree samplescripts of great variety
and broad range in complexity to consider a more
reliable proof of at least usability than the procedure
you applied?

My xturtle is certainly not bugfree. But it's (also
certainly) not worse than turtle.py and way more versatile.

A more courageous and less bureaucratic approach to the problem
would be appropriate. Perhaps combined with some fantasy.
For example: put turtle.py and  xturtle.py both into beta2 and
see which one stands better the (beta)test of time. Or perhaps you have
an even better idea!

Regards,
Gregor

P.S.: If this posting doesn't move points of view, at least
it reveals one fixable bug in turtle.py (albeit also one unfixable!)







> Regards,
> Martin
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