1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
"""
This module will contain helper functions that should assist in maintaining a
mostly functional way of programming.
It will also contain miscellaneous functions that can be used globally, and thus
do not fit well in any other module.
FUNCTIONS:
compose: This function is used to compose multiple functions into a single
function. It passes the results of calling one function to the other until
all the functions to be composed are called.
"""
from functools import reduce
def compose(*functions):
"""Compose multiple functions into a single function.
The utility in this function is not specific to this module, and as such,
this function can, and probably should, be moved to a more global module.
DESCRIPTION:
Given `cfn = compose(f_1, f_2, ... f_(n-1), f_n )`, calling
`cfn(arg_1, arg_2, ..., arg_m)` should call `f_n` with the arguments passed
to `cfn` and the results of that should be passed as arguments to `f_(n-1)`
and so on until `f_1` is called with the results of the cumulative calls and
that is the result of the entire chain of calls.
PARAMETERS:
functions: a variable argument list of function.
"""
def composed_function(*args, **kwargs):
return reduce(
lambda res, fn: fn(res),
reversed(functions[:-1]),
functions[-1](*args, **kwargs))
return composed_function
|
