Hi all --

several months ago, I cooked up a tool, Oscar for rigorously
type-checking a Python object graph: you define an object schema
(currently through specially-formatted class docstrings), and Oscar
crawls a persistent object graph to ensure that every scrap of data in
it conforms to your schema.  We use this regularly in the MEMS Exchange
for integrity-checking our ZODB database; it's not the be-all-end-all to
checking that all is well with an object database, but it's a hell of a
lot better than nothing.

In the past few weeks, I finally got around to writing the scripts and
documentation necessary to release Oscar publicly.  Now I'm ready to do
so, pending approval by the CNRI brass (sigh).  There's nothing
available for download just yet, so no chest-thumping post to
python-announce.  But there is documentation describing the Oscar type
language, which I think is a fine way to descibe Python data types.  So,
on the assumption that types-sig and zodb-dev readers are more likely
than most to want to rush out and try Oscar as soon as it's available,
I'm posting all that documentation right here.  I welcome feedback as to
whether this is a crazy idea or not, whether the type syntax is bogus or
excellent, whether the type-system is "good enough" or needs to be
all-encompassing, etc.

Attached you'll find:

  type-system.txt
    a description of Oscar's type system and the syntax for
    defining Oscar types
  schema.txt
    a description of what an object schema consists of and
    how you define one
  checking.txt
    how to use Oscar to type-check an existing persistent
    object graph

Enjoy!  Hopefully the real release will happen this week or next.

        Greg
-- 
Greg Ward - software developer                gward@[...].org
MEMS Exchange                            http://www.mems-exchange.org