[Zope] ZTUtils TabindexIterator class

[David Pratt]

Can I contribute a small TabindexIterator class for ZTUtils.  It is not 
big, but handy for generating tabindex values in a site. The current 
Iterator class available was not meant to do this but this is.  I think 
this could be added to Iterators.py  It seems better to incorporate 
something like this in ZTUtils than making a site tool to do this.

It only provides one method next() and takes a sequence. If you want 
your tabindex to start at 500 and go no further than 599, you just give 
it range(500,600) and stops iterating. For for 0 to n  - just use 
range(n).  It could always pass after iteration stops but I think it is 
better to raise exception so you can modify your sequence, if necessary.

class TabindexIterator:
	""" Tabindex iterator class """
	
	__allow_access_to_unprotected_subobjects__ = 1
	
	def __init__(self, seq):		
		self.iter = seq.__iter__()
		
	def next(self):
		try:
			next = self.iter.next()
			return next
		except StopIteration:
			raise 'Tabindex iterator exhausted.'

Regards,
David