Python Function composition

compose.py

from functools import partial
from typing import Protocol


class Callable(Protocol):
    def __call__(self, *args, **kwargs):
        ...


class Params:
    """Parameters to be passed to a function"""

    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs

    def __rlshift__(self, other: Callable) -> "Function":
        return Function(partial(other, *self.args, **self.kwargs))


class Function:
    """Composable Function"""

    def __init__(self, f: Callable):
        self.f = f

    def __call__(self, *args, **kwargs):
        return self.f(*args, **kwargs)

    def __mul__(self, other: Callable) -> "Function":
        return Function(lambda x: self(other(x)))

    def __rmul__(self, other: Callable) -> "Function":
        return Function(lambda x: other(self(x)))


class Call:
    """Application Operator"""

    def __call__(self, f: Callable):
        return f()

    @classmethod
    def __ror__(cls, other: Callable):
        return other()


c = Call()
P = Params
F = Function

fa = F(lambda x: x + "a")
fb = F(lambda x: x + "b")

print(f"{c(fa << P('x'))=}")
print(f"{fa << P('x') | c=}")
print(f"{fa * fb << P('x') | c=}")


"""
- https://docs.python.org/3/reference/datamodel.html
- https://docs.python.org/3/reference/expressions.html#operator-precedence
- https://en.wikipedia.org/wiki/Function_composition
- https://www.sfu.ca/~tjd/383summer2019/haskell_comp_and_app_lhs.html
"""