Django on Jython, Python Implementations and Performance

By Michael Foord -
Python is now in a very healthy position, with several major implementations: CPython, Jython, IronPython and PyPy. Python itself is very loosely specified (can anyone point me to the documentation for the __reversed__ method for example?). The specification is partly in the documentation and partly in CPython, which is called the 'reference implementation'.

This blog entry is about the different implementations of Python, which parts of Python are specification and which are implementation details and what it means to talk about the performance of Python in the light of the different implementations.
UPDATE: It turns out that documentation for __reversed__ was added to the Python 2.6 docs in January. However it (currently) incorrectly states that it is new in 2.6 when it was in fact new in Python 2.4.

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