`functools.pipe`

[dg-pb]

@Wombat

Flexibility: Functional code needs more than a chain a maps. Along the way, pipelines need starmap, filter, filterfalse, islicing, teeing, and grouping. The functools.pipe does not support any of that, nor does it handle keyword arguments or multiple positional arguments.

This concept is for single argument function composition. Not to be confused with iterator piping.

Having that said, composing iterator functions via function composition achieves linear iterator piping.

E.g.:

pipeline = pipe(
    partial(filter, lambda x: x % 2),
    partial(map, lambda x: x/2),
    list
)
pipeline([0, 1, 2, 3, 4])
# [0.5, 1.5]

For more complex iterator piping (multiple argument function composition) there is a FunctionType for that.

@Wombat

Debugability: Mushing the calls into a single call would be challenging for debugging so that it is hard to add logging or breakpoints.

For outer (outside of member functions) logging / debugging, one can write a function to mix into a pipeline. E.g.:

def log_debug(x, is_iterator=False):
    if is_iterator:
        for el in x:
            breakpoint()
            print(x)
            yield x
    else:
        breakpoint()
        print(x)
    return x