helper functions to convert between higher-order and lower order

[eriknw]

It could be convenient to have a function that turns a first order function into a higher-order function (i.e. a "decorator" decorator), and vice versa. Crude examples are below:

def identity(x):
    return x

def higher(f):
    def outer(g):
        def inner(*args, **kwargs):
            return f(g(*args, **kwargs))
        return inner
    return outer

def lower(f):
    return f(identity)

# Test functions
def double(x):
    return 2 * x

def doubled(f):
    def inner(*args, **kwargs):
        return 2 * f(*args, **kwargs)
    return inner

highdouble = higher(double)
lowdouble1 = lower(highdouble)
lowdouble2 = lower(doubled)

assert doubled(lambda: 10)() == 20
assert highdouble(lambda: 10)() == 20
assert double(10) == 20
assert lowdouble1(10) == 20
assert lowdouble2(10) == 20

[eriknw]

Heh, functionalize and defunctionalize.