gamla 43

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גamla is a functional programming library for python which is performant and supports async.

Installation

pip install gamla

Debugging anonymous compositions

gamla.compose(x, y, z) produces a new function which doesn't have a proper name. If x raises an exception, it is sometimes hard to figure out where this occurred. To overcome this, set the env variable GAMLA_DEBUG_MODE (to anything). This will cause the composition functions to give a name for the anonymous composition. The name would be a concatenation of its constituents' names, e.g. x_of_y_of_z. The name is given in a way that persists to the stack exceptions.

This is turned on only by flag because it incurs significant overhead so things might get slow.

Mixing asynchronous and synchronous code

Most functions in this lib will work seamlessly with async and regular functions, and allow the developer to focus on the logic instead of deciding where to place an await.

For example:

import asyncio

import gamla


def increment(i):
    return i + 1


async def increment_async(i):
    asyncio.sleep(1)
    return i + 1


async def run():
    mixed_composition = gamla.compose_left(increment, increment_async, increment)
    return await mixed_composition(0)  # returns 3!

Migrating from toolz

The main problems - toolz is slow and does not support async functions.

Why is it slow?

It uses the expensive inspect module to look at a function’s arguments, and doing so at each run. This happens not only on curried functions, but in compositions as well.

Why does gamla not suffer from this problem?

Two reasons:

1. It does no longer support binary signatures on things like map, so it doesn’t need to infer anything (these are higher order functions in gamla).
2. The gamla.curry function pays for the signature inspection in advance, and remembers its results.

Function mapping and common gotchas (written in blood):

• curried.(filter|map|valmap|itemmap|keymap) -> gamla.$1 (make sure the call is with a single argument)
• toolz.identity -> gamla.identity
• toolz.contains -> gamla.contains
• toolz.lt -> gamla.greater_than
• toolz.gt -> gamla.less_than
• toolz.ge -> gamla.less_equals
• toolz.le -> gamla.greater_equals
• toolz.filter(None) -> gamla.filter(gamla.identity)
• toolz.excepts(a, b, c) -> gamla.excepts(a, c, b)
• toolz.excepts(a, b) -> gamla.excepts(a, gamla.just(None), b) (following the “data-last” currying convention)

Releasing a new version

1. Create a pypi account.
2. Download twine and give it your pypi credentials.
3. Get pypi permissions for the project from its owner.
4. python setup.py sdist bdist_wheel; twine upload dist/*; rm -rf dist;