[Stackless] Sudden error with pyexpat

[Santiago Gala]

El dom, 10-02-2008 a las 22:28 +0100, Andrew Dalke escribió:
> On Feb 10, 2008, at 10:47 AM, Simon Pickles wrote:
> > I've been using ElementTree for a few weeks without problem, with
> > Stackless Python.
> >
> > Suddenly I have an error importing expat, in both application and  
> > console:
> 
> 
> >     from pyexpat import *
> > ImportError:
> > /usr/lib/python2.5/site-packages/_xmlplus/parsers/pyexpat.so:  
> > undefined
> > symbol: PyUnicodeUCS4_Decode
> >>>>
> >
> > On the python mailing list, I got this response:
> >
> > "You changed the build-time configuration of your Python  
> > installation, so you
> > should rebuild PyXML for the new interpreter (or uninstall it, as  
> > you don't
> > need it for ElementTree)."
> >
> > Does this mean Stackless is confusing the pyexpat.so library? Why  
> > would it work last week?
> 
> 
> Python supports two different internal representation for Unicode -  
> UCS2 and US4.  These are 16-bit and 32-bit internal representations.
> 
> The choice is a compile time option, and it depends on the vendor,  
> and sometimes you can select one version or the other.
> 
> Ubuntu I believe ships as UCS-4.
> 
> What did you compile Stackless Python as?  It's a compile-time option.
> 
> To find out, look at sys.maxunicode.  My machine is compile for UCS-2 so
> 
>  >>> sys.maxunicode
> 65535
> 
> That should be a lot larger for UCS-4.  Or do
> 
>  >>> unichr(0x10000)
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> ValueError: unichr() arg not in range(0x10000) (narrow Python build)
> 

>>> sys.maxunicode
1114111

for a UCS4 build. Most linuxes are currently using UCS4 builds.

WRT package manager, I can't remember the magic incantation to get what
package a file belongs to, but something like:

dpkg-query
-S /usr/lib/python2.5/site-packages/_xmlplus/parsers/pyexpat.so

should tell you if the file came from a package, and then you can use
the package manager to remove it.

Regards
Santiago


> 
> 
> This error message looks like you installed the third-party "PyXML"  
> package for Python.  That's what uses the "_xmlplus" directory.  When  
> did you install that package?  Why?  It's unmaintained.  Python's  
> standard distribution include an expat parser, so you don't need that  
> extension.
> 
>     http://docs.python.org/lib/module-xml.parsers.expat.html
> 
> 
> I can't help with Ubuntu.  I get confused by package managers.
> 
> 
> 				Andrew
> 				dalke at dalkescientific.com
> 
> 
> 
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