[Python-Dev] Function Operators

[Christopher Olah]

Dear python-dev,

In mathematical notation, f*g = z->f(g(z)) and f^n = f*f*f... (n
times). I often run into situations in python where such operators
could result in cleaner code. Eventually, I decided to implement it
myself and see how it worked in practice.

However, my intuitive implementation [1] doesn't seem to work. In
particular, despite what it says in function's documentation, function
does not seem to be in __builtin__. Furthermore, when I try to
implement this through type(f) (where f is a function) I get invalid
syntax errors.

I hope I haven't made some trivial error; I'm rather inexperienced as
a pythonist.

Christopher Olah


[1] Sketch:

def __builtin__.function.__mul__(self, f):
    return lambda x: self(f(x))

def __builtin__.function.__pow__(self, n):
    return lambda x: reduce(lambda a,b: [f for i in range(n)]+[x])