I often need to write quite DSLs and file formats. I like John
Aycock's SPARK system, but it is written in quite unidiomatic
python. This is a fairly simple modification, mostly transferring to
use decorators rather than docstrings for rule definitions, but also
with some other tweaks.

It is a library mostly for my own use, so I'd recommend you take care
to read the source and check out my modifications before you consider
using it.

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Modifications copyright (c) 2006-2010 Ian Millington. 
See the LICENSE file for details.

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Copyright (c) 1998-2000 John Aycock

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