On Thu, 13 Nov 2008 19:52:13 -0700, Joe Strout wrote:
> Pity there isn't a way for a function to get a reference to itself
> except by name. Still, when you rename a method, you're going to have
> to update all the callers anyway -- updating a couple of extra
> references within the method is not that much extra effort.
I have come across a situation where this was a problem.
I was writing a bunch of different versions of the classic factorial and
Fibonacci functions, some iterative, some recursive, some with caches,
and some without. What I wanted to do was do something like this (for
factorial):
def iterative_without_cache(n):
product = 1
for i in xrange(1, n+1):
product *= i
return product
iterative_with_cache = decorate_with_cache(iterative_without_cache)
which works. But it doesn't work for the recursive version:
def recursive_without_cache(n):
if n <= 1:
return 1
else:
return n*recursive_without_cache(n-1)
recursive_with_cache = decorate_with_cache(recursive_without_cache)
for obvious reasons. Solution: the copy-and-paste anti-pattern. Good
enough for test code, not for real work.
Now multiply the above by about a dozen slightly different recursive
versions of the Fibonacci function, and you will see why it was a problem.
--
Steven
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