[Edu-sig] Visual Programming in Python?
jpsandys at yahoo.com
Fri Apr 21 21:40:51 CEST 2006
Ian Bicking wrote:
> As to the merits of Logo as a language and Python as a language,
> I'm not sure. Logo is grammatically simpler. Generally it is
> more insulated from the underlying implementation. It isn't
> burdened with ideas like "good software engineering".
I will respectively disagree with your comments, but arguements
about these points would be counterproductive.
>Jeff Sandys wrote:
>> What I would like to see in a turtle environment comes from
>> StarLogo ( http://education.mit.edu/starlogo/ ). StarLogo has
>> multiple turtles, the turtles can inherit methods to make new
>> turtle classes, and the background also has methods for its cells,
>> implementing Conway's Life only takes several lines. ...
>> I think that creating a StarPython, with Python syntax, would be
>> ... valuable ...
> That's hard, or maybe easy.
> With CPython, something like StarPython is hard. The kind of
> concurrency it does isn't practical with OS threads. Maybe with
> Greenlets, though I must admit I don't understand them.
Why? StarLogo is written in Java, I do not believe that it is
threaded. Threads would be nice but I don't think they are
necessary to create StarLogo functionality in Python.
>> Python would be easier to teach if it had clearer error messages.
> Error messages are indeed hard. It's easier when you have a
> clear idea of system and user code. In a typical Logo
> implementation where the library is implemented in a language
> other than Logo, it's easy to tell what is inside and outside --
> everything in Logo belongs to the programmer, everything not in
> Logo belongs to the system. In Python it is not so easy,
> especially because errors often bubble up from deep in system
> code, and you actually have to inspect the system code to
> understand what it means in the context of your code. As an
> shutil(None, 'tmp'):
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> File "/usr/lib/python2.4/shutil.py", line 81, in copy
> copyfile(src, dst)
> File "/usr/lib/python2.4/shutil.py", line 41, in copyfile
> if _samefile(src, dst):
> File "/usr/lib/python2.4/shutil.py", line 31, in _samefile
> return os.path.samefile(src, dst)
> File "/usr/lib/python2.4/posixpath.py", line 218, in samefile
> s1 = os.stat(f1)
> TypeError: coercing to Unicode: need string or buffer, NoneType found
> Sigh. It's not like hiding that traceback can make that error
> more understandable. I really don't know how to resolve that.
> Though it definitely is possible to trim exceptions down. For
> instance, not to show code that is part of the standard library
> (or at least filter that out unless explicitly expanded). That
> won't make the exception make sense (coerce to Unicode?! talk
> about obscure), but at least it will better highlight the
> problem code.
How would you attack this problem to get a Logo like error message,
"shutil didn't like None as an input"? I would be interested in
contributing to an errors for beginners project.
Thanks -- Jeff Sandys
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