[XML-SIG] saxlib and enumerations

[Paul Prescod]

Okay, I've translated a Java SAX program to Python to make sure that our
interface is the same as theirs. After some fiddling with my JPython
installation, I successfully parsed an XML document based on a Java
parser (Microstar's AELFred). I was hoping to be able to be able to
parse using Python programs with no change, but failed in my first test,
with xmllib.py and xlsax.py.

Here's what my Java-trasnlated code to handle attributes looks like:

	attNames = atts.getAttributeNames()
	while (attNames.hasMoreElements()):
      		aname = attNames.nextElement()
		...
attNames is a Java "enumeration object". Of course the Python equivalent
is a sequence. So the code would look like this if I was using a Python
parser:

	attNames = atts.getAttributeNames()
	for (aname in attNames.hasMoreElements()):
		...

I can think of three ways to address this:

 #1. We could abandon the idea of using Java parsers directly in
JPython, and always require a thin "wrapper" that translates Java
enumerations to Python sequences.

 #2. We could ask Jim to wrap *all* Java enumerations in Python
sequences.

 #3. We could port the Java "enumeration" concept to Python for use with
saxlib.

 Paul Prescod  - http://itrc.uwaterloo.ca/~papresco

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