[Python-3000] Type Comparisons with Godel Numbers

[Collin Winter]

On 4/22/06, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> This is worth thinking about. Recently when pondering the
> question of when it would or would not be appropriate to
> put in type assertions to help catch bugs, I concluded
> that it makes the most sense to do so when building a
> data structure, but not when just passing things around
> between calls.
>
> The most difficult-to-debug type errors are the ones
> where you've put something of the wrong type into a
> data structure, and it's sat there for a while not
> causing any obvious problem until something else
> tries to use it, by which time most evidence of where
> it came from is gone.

Inspired by this post, I've implemented this functionality in my
typecheck package[1]. Traditionally, the package has offered only
decorator-based type assertions for a function's arguments and return
values and a generator's yield values. To complement this, I've coded
up an assert_type function that's intended to be used just as Greg has
described.

Documentation for assert_type is available[2] from the project's
website, as is a tarball of the latest SVN revision[3] (assert_type
will go into the upcoming 0.4 release) so all interested parties can
play around with this.

[1] - http://oakwinter.com/code/typecheck/
[2] - http://oakwinter.com/code/typecheck/dev/tutorial/assert_type.html
[3] - http://oakwinter.com/code/typecheck/dist/typecheck-svn-latest.tar.gz

Collin Winter