smonad 0.3

smonad - a functional library

Introduction

What?

Monads in python, with some helpful functions.

This package is a fork of Philip Xu’s excellent monad package. Philip’s package has been modified to be more approachable for Python developers. It takes some inspiration from the excellent lambda library for Java and Scala’s Try monad

How?

>>> from smonad.decorators import maybe
>>> parse_int = maybe(int)
>>> parse_int(42)
Just(42)
>>> parse_int('42')
Just(42)
>>> parse_int('42.2')
Nothing

>>> parse_float = maybe(float)
>>> parse_float('42.2')
Just(42.2)

>>> from smonad.actions import tryout
>>> parse_number = tryout(parse_int, parse_float)
>>> tokens = [2, '0', '4', 'eight', '10.0']
>>> [parse_number(token) for token in tokens]
[Just(2), Just(0), Just(4), Nothing, Just(10.0)]

>>> @maybe
... def reciprocal(n):
...     return 1. / n
>>> reciprocal(2)
Just(0.5)
>>> reciprocal(0)
Nothing

>>> process = parse_number >> reciprocal
>>> process('4')
Just(0.25)
>>> process('0')
Nothing
>>> [process(token) for token in tokens]
[Just(0.5), Nothing, Just(0.25), Nothing, Just(0.1)]
>>> [parse_number(token) >> reciprocal for token in tokens]
[Just(0.5), Nothing, Just(0.25), Nothing, Just(0.1)]
>>> [parse_number(token) >> reciprocal >> reciprocal for token in tokens]
[Just(2.0), Nothing, Just(4.0), Nothing, Just(10.0)]

Why?

Why not.

Requirements

• CPython >= 2.7

Installation

Install from PyPI:

pip install smonad

Install from source, download source package, decompress, then cd into source directory, run:

make install

License

BSD New, see LICENSE for details.

Links

Documentation:

http://smonad.readthedocs.org/

Issue Tracker:

https://github.com/bryanwb/smonad/issues/

Source Package @ PyPI:

https://pypi.python.org/pypi/smonad/

Git Repository @ Github:

https://github.com/bryanwb/smonad/