design of python: why is assert a statement and not a function?

Question

In Python, assert is a statement, and not a function. Was this a deliberate decision? Are there any advantages to having assert be a statem

Answer 1

One of the wonderful things about assert in python and in other languages (specifically C) is that you can remove them to optimize your code by just adding the correct #define (optionally on the commandline with any compiler I've ever used) or optimization flags (-O in python). If assert became a function, this feature would be impossible to add to python as you don't know until runtime whether you have the builtin assert function or user-defined function of the same name.

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Also note that in python, function calls are reasonably expensive. Replacing inline with the code if __debug__: ... is probably a lot more efficient than doing a function call which could be significant if you put an assert statement in a performance critical routine.