[Python-Dev] SF patch 864863: Bisect C implementation (original) (raw)

Raymond Hettinger python at rcn.com
Tue Dec 30 23:27:03 EST 2003

[Raymond]

Dmitry Vasiliev has submitted a C implementation for the bisect module.

My thoughts are to accept it with the following changes: * leave the original code intact for teaching purposes * import the C version from bisect * make sure the C code is not list specific and will work with any container supporting len(), getitem(), and insert(). Do you guys have any objections?

[Guido] > Only that I wished you had done the same for heapq.py.

[Tim]

It's not too late. IIRC, neither you nor I could make time to review the heapq plans before the C code got checked in. I was able to make a little time after, and mourned the loss of the educational value of the Python version (to Raymond, in pvt).

I would be happy to bring back the python version and make it coexist with the C version. IMO, it was a programming pearl unto itself and efforts were already made to preserve the extensive module docstring and make the code match the original line for line with the variable names and logic intact.

The bisect module warrants even more consideration because it is more basic and more venerable.

[Tim]

Nobody can sanely accuse me of not caring about speed (see a decade of speed-obsessed Python checkins for counterexamples ), but I cry a little each time a piece of the system gets recoded in C. Keeping the original Python code around is a nice compromise (pioneered, IIRC, by string.py, a loooong time ago).

Also, with the PyPy project, there is a chance that cleanly coded pure python modules will survive the test of time longer than their C counterparts. In the itertools module, I documented pure python equivalents to make the documentation more specific, to enchance understanding, and to make it easier to backport. For the most part, that effort was successful.

The only downside is the double maintenance problem of keeping the two in sync. Given the stability of bisect, that is not much of an issue.

Raymond Hettinger

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