[Python-Dev] interesting article on regex performance

[Collin Winter]

On Fri, Mar 12, 2010 at 11:29 AM,  <skip at pobox.com> wrote:
>
>    >> There are major practical problems associated with making such a leap
>    >> directly (Google's re2 engine is in C++ rather than C and we'd have
>    >> to keep the existing implementation around regardless to handle the
>    >> features that re2 doesn't support).
>
>    Collin> I don't see why C++ would be a deal-breaker in this case, since
>    Collin> it would be restricted to an extension module.
>
> Traditionally Python has run on some (minority) platforms where C++ was
> unavailable.  While the re module is a dynamically linked extension module
> and thus could be considered "optional", I doubt anybody thinks of it as
> optional nowadays.  It's used in the regression test suite anyway.  It would
> be tough to run unit tests on such minority platforms without it.  You'd
> have to maintain both the current sre implementation and the new re2
> implementation for a long while into the future.

re2 is not a full replacement for Python's current regex semantics: it
would only serve as an accelerator for a subset of the current regex
language. Given that, it makes perfect sense that it would be optional
on such minority platforms (much like the incoming JIT).

Collin