[Zope3-dev] The Date Time and TimeZone question

[Guido van Rossum]

> > I have no desire to couple Python's standard datetime implementation
> > to a 3rd party library.  Nor does Zope, I'm sure.
> 
> Why not? There is an excellent one at http://cr.yp.to/libtai.html.
> It's public domain, implements TAI (not UTC) and is very
> fast. Additionally the value space covers the lifetime of the
> universe and fractional seconds up to attoseconds are supported.

It seems to be out of date; the last leap second table update was
years ago:

    "The leap-second table was updated on 1998-07-25 for a leap second
    on 1998-12-31. There was no leap second on 1999-06-30.  There was
    no leap second on 1999-12-31. There was no leap second on
    2000-06-30."

It's not been ported to a wide enough range of platforms:

    "This version of libtai requires a UNIX system with
    gettimeofday(). It will be easy to port to other operating systems
    with compilers supporting 64-bit arithmetic"

The licensing situation is unclear (note that "public domain" has no
semantics):

    "The libtai source code is in the public domain."

Requiring Python users to download, attempt to compile and install a
3rd party library in order to be able to build Python is out of the
question.  Distributing it with Python is also out of the question --
even if Bernstein would license it to us, we'd still be responsible
for fixing bugs in it.

Summarizing: not a job I'm interested in taking on.  But I encourage
you to create your own wrapper for libtai and make it available to
interested Python users through the Vaults of Parnassus, though.

--Guido van Rossum (home page: http://www.python.org/~guido/)