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

Sept. 12, 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"?>
<root>foo<x:tag
xmlns:x="http://example.com/x"><!--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

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

Mathias Panzenböck