In article <[EMAIL PROTECTED]>, [EMAIL PROTECTED] wrote: > Just: > > > Btw. I find the use of a nested function here completely bogus: you > > don't need the surrounding scope. > > I don't agree, nested functions are useful to better structure your > program: to really nest things that are logically nested, to have just > one thing when you have only one thing to do, and they help you to > avoid polluting the namespace (those were the main purposes of nested > functions in Pascal-like languages).
Luckily this is Python, not Pascal :) 1. The fact that one function calls the other doesn't mean they're "logically nested". 2. The helper function is useful on its own, so it is a waste to hide it inside another. 3. The nested function makes the enclosing function harder to read. 4. I don't buy the namespace pollution argument, we have modules after all. 5. Overhead: every time a new function object is created, for no good reason. (But you save a global name lookup, yet that doesn't appear to weigh up against the function def. [*]) To me, nested functions (in Python) are *only* helpful when using closures. If you're not using the enclosing scope, you're just obfuscating things. Just [*] % python2.4 -m timeit -s "def helper(): pass" "def nonnesting():" \ " helper()" "nonnesting()" 1000000 loops, best of 3: 1.92 usec per loop % python2.4 -m timeit "def nesting():" " def helper(): pass" \ " helper()" "nesting()" 100000 loops, best of 3: 2.04 usec per loop -- http://mail.python.org/mailman/listinfo/python-list
