Re: CENSORSHIP - Django Project (Schema Evolution Support)
Ilias Lazaridis wrote:
> [posted publicly to comp.lang.python, with email notification to 6
> recipients relevant to the topic]
>
> I have implemented a simple schema evolution support for django, due to
> a need for a personal project. Additionally, I've provided an Audit:
>
> http://case.lazaridis.com/wiki/DjangoAudit
>
> As a result, I was censored ('banned' from the development list)
Please see this message for background:
http://groups.google.com/group/django-users/msg/5a96eabf75f2b9c7
To summarise, it was felt that Ilias was deliberately trolling the
mailing list. No further explanation seems necessary.
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Pythonic API design: detailed errors when you usually don't care
Hi all, I have an API design question. I'm writing a function that can either succeed or fail. Most of the time the code calling the function won't care about the reason for the failure, but very occasionally it will. I can see a number of ways of doing this, but none of them feel aesthetically pleasing: 1. try: do_something() except HttpError: # An HTTP error occurred except ApplicationError: # An application error occurred else: # It worked! This does the job fine, but has a couple of problems. The first is that I anticipate that most people using my function won't care about the reason; they'll just want a True or False answer. Their ideal API would look like this: if do_something(): # It succeeded else: # It failed The second is that the common path is success, which is hidden away in the 'else' clause. This seems unintuitive. 2. Put the method on an object, which stores the reason for a failure: if obj.do_something(): # It succeeded else: # It failed; obj.get_error_reason() can be called if you want to know why This has an API that is closer to my ideal True/False, but requires me to maintain error state inside an object. I'd rather not keep extra state around if I don't absolutely have to. 3. error = do_something() if error: # It failed else: # It succeeded This is nice and simple but suffers from cognitive dissonance in that the function returns True (or an object evaluating to True) for failure. 4. The preferred approach works like this: if do_something(): # Succeeded else: # Failed BUT this works too... ok = do_something() if ok: # Succeeded else: # ok.reason has extra information reason = ok.reason This can be implemented by returning an object from do_something() that has a __nonzero__ method that makes it evaluate to False. This solves my problem almost perfectly, but has the disadvantage that it operates counter to developer expectations (normally an object that evaluates to False is 'empty'). I know I should probably just pick one of the above and run with it, but I thought I'd ask here to see if I've missed a more elegant solution. Thanks, Simon -- http://mail.python.org/mailman/listinfo/python-list
Treating a unicode string as latin-1
Hello,
I'm using ElementTree to parse an XML file which includes some data
encoded as cp1252, for example:
Bob\x92s Breakfast
If this was a regular bytestring, I would convert it to utf8 using the
following:
>>> print 'Bob\x92s Breakfast'.decode('cp1252').encode('utf8')
Bob's Breakfast
But ElementTree gives me back a unicode string, so I get the following
error:
>>> print u'Bob\x92s Breakfast'.decode('cp1252').encode('utf8')
Traceback (most recent call last):
File "", line 1, in
File "/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/encodings/cp1252.py", line 15, in decode
return codecs.charmap_decode(input,errors,decoding_table)
UnicodeEncodeError: 'ascii' codec can't encode character u'\x92' in
position 3: ordinal not in range(128)
How can I tell Python "I know this says it's a unicode string, but I
need you to treat it like a bytestring"?
Thanks,
Simon Willison
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Is it possible to consume UTF8 XML documents using xml.dom.pulldom?
I'm having a horrible time trying to get xml.dom.pulldom to consume a
UTF8 encoded XML file. Here's what I've tried so far:
>>> xml_utf8 = """
Simon\xe2\x80\x99s XML nightmare
"""
>>> from xml.dom import pulldom
>>> parser = pulldom.parseString(xml_utf8)
>>> parser.next()
('START_DOCUMENT', )
>>> parser.next()
('START_ELEMENT', )
>>> parser.next()
...
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2019' in
position 21: ordinal not in range(128)
xml.dom.minidom can handle the string just fine:
>>> from xml.dom import minidom
>>> dom = minidom.parseString(xml_utf8)
>>> dom.toxml()
u'Simon\u2019s XML nightmare'
If I pass a unicode string to pulldom instead of a utf8 encoded
bytestring it still breaks:
>>> xml_unicode = u'Simon\u2019s XML nightmare'
>>> parser = pulldom.parseString(xml_unicode)
...
/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/
xml/dom/pulldom.py in parseString(string, parser)
346
347 bufsize = len(string)
--> 348 buf = StringIO(string)
349 if not parser:
350 parser = xml.sax.make_parser()
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2019' in
position 32: ordinal not in range(128)
Is it possible to consume utf8 or unicode using xml.dom.pulldom or
should I try something else?
Thanks,
Simon Willison
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Re: Is it possible to consume UTF8 XML documents using xml.dom.pulldom?
Follow up question: what's the best way of incrementally consuming XML in Python that's character encoding aware? I have a very large file to consume but I'd rather not have to fall back to the raw SAX API. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to consume UTF8 XML documents using xml.dom.pulldom?
On Jul 30, 4:43 pm, Paul Boddie <[EMAIL PROTECTED]> wrote:
> I can't reproduce this on Python 2.3.6 or 2.4.4 on RHEL 4. Instead, I
> get the usual...
>
> ('CHARACTERS', )
I'm using Python 2.5.1 on OS X Leopard:
$ python
Python 2.5.1 (r251:54863, Feb 4 2008, 21:48:13)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
I just tried it out on Python 2.4.2 on an Ubuntu machine and it worked
fine! I guess this must be an OS X Python bug. How absolutely
infuriating.
Thanks,
Simon
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Re: Is it possible to consume UTF8 XML documents using xml.dom.pulldom?
On Jul 30, 4:59 pm, Simon Willison <[EMAIL PROTECTED]> wrote: > I just tried it out on Python 2.4.2 on an Ubuntu machine and it worked > fine! I guess this must be an OS X Python bug. How absolutely > infuriating. Some very useful people in #python on Freenode pointed out that my bug occurs because I'm trying to display things interactively in the console. Saving to a variable instead fixes the problem. Thanks for your help, Simon -- http://mail.python.org/mailman/listinfo/python-list
