[Python-ideas] xml generator that uses the with statement

Mathias Panzenböck grosser.meister.morti at gmx.net
Sat Sep 13 00:57:30 CEST 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:
>>> 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"?>
foo="bar" egg="spam"></tag></root>

I'm not 100% sure about some parts of the 'syntax', though.
E.g. maybe change this:

>>> with xm.tag(x='y').ns('...'):
>>> 	with xm.tag:
>>> 		...

into this:

>>> 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:

>>> 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:

>>> 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? :)


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