Re: self modifying code

Robin Becker <robin@xxxxxxxxxxxxxxxxxxx> writes:

When young I was warned repeatedly by more knowledgeable folk that self
modifying code was dangerous.

Is the following idiom dangerous or unpythonic?

def func(a):
global func, data
data = somethingcomplexandcostly()
def func(a):
return simple(data,a)
return func(a)

1. I don't think most people would call that "self-modifying code". I
won't try defining that term precisely because I know you'll just
pick holes in my definition ;-)

2. The use of global func is just plain weird :-)

3. Peter Otten's version is OK, but how about this, using a closure
instead of globals (UNTESTED)

def make_func():
namespace = object()
namespace.data = None
def func(a):
if namespace.data is None:
namespace.data = somethingcomplexandcostly()
return simple(namespace.data, a)
return func
func = make_func()


John

.

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