Comments invited: PEP 279 Enhanced Generators

[Raymond Hettinger]

Your review and comments are invited for PEP 279:
   http://python.sourceforge.net/peps/pep-0279.html

In summary, it proposes:

1.  Four new built-in functions:  xmap, xfilter, xzip, and indexed
2.  Generator comprehensions:  [yield int(x) for x in floatgen()]
3.  Feeding data into a generator using an optional argument to .next()
4.  Providing a mechanism to raise exceptions in a generator

This version incorporates all of the critiques I received on earlier
discussion drafts.  The key changes from the earliest draft are:

- xmap, xfilter, and xzip now exactly mimic map, filter, and zip
- index() was renamed to indexed()
- ints() is no longer being proposed
- generator comprehensions now exactly mimic list comprehensions
- .next(arg) is used instead of a separate .submit() method
- control flow is now the same whether or not 'x=yield None' is used
- .throw(exception) is now a separate part of the proposal


Raymond Hettinger