LXML: can't register namespace

[Stefan Behnel]

Steven D'Aprano schrieb am 09.03.2018 um 12:41:
> On Fri, 09 Mar 2018 10:22:23 +0100, Stefan Behnel wrote:
> 
>> Andrew Z schrieb am 07.03.2018 um 05:03:
>>> Hello,
>>>  with 3.6 and latest greatest lxml:
>>>
>>> from lxml import etree
>>>
>>> tree = etree.parse('Sample.xml')
>>> etree.register_namespace('','http://www.example.com')
>>
>> The default namespace prefix is spelled None (because there is no prefix
>> for it) and not the empty string.
> 
> Is that documented somewhere?

http://lxml.de/tutorial.html#namespaces


> Is there a good reason not to support "" as the empty prefix?

Well, the "empty prefix" is not an "empty" prefix, it's *no* prefix. The
result is not ":tag" instead of "prefix:tag", the result is "tag".

But even ignoring that difference, why should the API support two ways of
spelling the same thing, and thus encourage users to write diverging code?

Stefan