Quicksort using the Y Combinator (lambda calculus) in pure Python

quicksort_y_combinator_lambda_calculus.py

# Quicksort using the Y Combinator (lambda calculus) in pure Python

>>> Y = lambda f: lambda *args: f(Y(f))(*args)

>>> quicksort = Y(lambda f:
...     lambda x: (
...         f([item for item in x if item < x[0]])
...         + [y for y in x if x[0] == y]
...         + f([item for item in x if item > x[0]])
...     ) if x else [])

>>> quicksort([1, 3, 5, 4, 1, 3, 2])
[1, 1, 2, 3, 3, 4, 5]