Mailman 3 xml generator that uses the with statement - Python-ideas

13 Sep 2008


      Here is a quick and dirty draft of a xml generator that uses the with statement:
http://twoday.tuwien.ac.at/pub/files/XmlMarkup (ZIP, 3 KB)
It is inspired by rubies XmlMarkup class.
Brief usage:
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from __future__ import with_statement
from XmlMarkup  import *
import sys
with XmlMarkup(sys.stdout) as xm:
   with xm.root:
   	xm.text('foo')
   	with xm.prefixMapping('x','http://example.com/x'):
   		with xm.tag.ns('http://example.com/x'):
   			xm.comment('comment')
   		with xm['text']:
   			xm.text('bar')
   	with xm.tag(foo='bar',egg='spam'):
   		pass
<?xml version="1.0" encoding="utf-8"?>
<root>foo<x:tag
xmlns:x="http://example.com/x%22%3E<!--comment--></x:tag><text>bar</text><tag
foo="bar" egg="spam"></tag></root>
I'm not 100% sure about some parts of the 'syntax', though.
E.g. maybe change this:
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with xm.tag(x='y').ns('...'):
   with xm.tag:
   	...
into this:
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with xm.tag('...',x='y'):
   with xm.tag():
   	...
This Syntax is more concise than those unhandy and error prone
beginElement/endElement calls (endElement needs the name as argument, too!).
This way you never forget to close a tag again. :)
It even provides a simple way to embed arbitrary data:
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with xm.text as text:
   # text is a pseudo file object
   with XmlMarkup(text) as xm2:
   	# things you generate with xm2 will be escaped
And I added a way to generate DTDs:
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with xm.dtd('foo') as dtd:
   dtd.element('a',oneof('x','y',PCDATA))
   dtd.element('x',('egg','bacon',many('spam')))
   dtd.attlist('a',att1 = (CDATA, DEFAULT, 'value'), att2 = (ID, REQUIRED))
   dtd.entity('ent','value')
What do you think? :)
-panzi