Hola Compai!

Compai core functions

compose(*F)

Compose the list of functions in F from right to left

Parameters:

Name	Type	Description	Default
F	List[Callable]	List of functions	()

Examples:

>>> compose(lambda x: x + 1, lambda x: x * 2)(5)
11
>>>

Source code in compai/compai.py

def compose(*F: List[Callable]):
    """Compose the list of functions in F from right to left

    Arguments:
        F: List of functions

    Examples:
    ```pycon
    >>> compose(lambda x: x + 1, lambda x: x * 2)(5)
    11
    >>>
    ```
    """
    return reduce(lambda f, g: lambda x: f(g(x)), F)

const(x)

Returns a function that will always return x.

Parameters:

Name	Type	Description	Default
x	~T	Any value	required

Examples:

>>> f = const('foo')
>>> f()
'foo'
>>> f(1, a='brr')
'foo'
>>>

Source code in compai/compai.py

def const(x: T) -> Callable[..., T]:
    """Returns a function that will always return `x`.

    Arguments:
        x: Any value

    Examples:
    ```pycon
    >>> f = const('foo')
    >>> f()
    'foo'
    >>> f(1, a='brr')
    'foo'
    >>>
    ```
    """

    return lambda *_, **__: x

dict_map(**fs)

Map especific elements in a dict.

Examples:

>>> dict_map(a=int, b=str)(dict(a='1', b=123, c=True))
{'a': 1, 'b': '123', 'c': True}
>>>

Source code in compai/compai.py

def dict_map(**fs):
    """Map especific elements in a dict.

    Examples:
    ```pycon
    >>> dict_map(a=int, b=str)(dict(a='1', b=123, c=True))
    {'a': 1, 'b': '123', 'c': True}
    >>>
    ```
    """

    def _change_dict(d):
        d = d.copy()

        for k, f in fs.items():
            if k in d:
                d[k] = f(d[k])

        return d

    return _change_dict

length(xs)

Returns the length of xs.

Examples:

>>> length([1, 2, 3])
3
>>> length(range(10))
10
>>> length(None for _ in range(10))
10
>>>

Source code in compai/compai.py

def length(xs):
    """Returns the length of xs.

    Examples:
    ```pycon
    >>> length([1, 2, 3])
    3
    >>> length(range(10))
    10
    >>> length(None for _ in range(10))
    10
    >>>
    ```
    """

    len_ = getattr(xs, '__len__', None)

    def default_len():
        return sum(1 for _ in xs)

    return compose(
        apply,
        none_map(identity, if_none=const(default_len))
    )(len_)

none_map(func, if_none=None)

Returns a function that will call func if the argument is not none, and return if_none otherwise.

Examples:

>>> f = none_map(str, if_none=const(1))
>>> f(1)
'1'
>>> f(None)
1
>>>

Source code in compai/compai.py

def none_map(func, if_none=None):
    """Returns a function that will call func if the argument is not none, and return if_none otherwise.

    Examples:
    ```pycon
    >>> f = none_map(str, if_none=const(1))
    >>> f(1)
    '1'
    >>> f(None)
    1
    >>>
    ```
    """

    @wraps(func)
    def _func(x):
        if x is not None:
            return func(x)

        return if_none()

    return _func

tuple_map(*fs)

Returns a function that will apply every f_i for evey element of the tuple argument.

Examples:

>>> inc = lambda x: x + 1
>>> tuple_map(None, inc)((1, 2))
(1, 3)
>>> tuple_map(inc)((1, 2))
(2, 2)
>>>

Source code in compai/compai.py

def tuple_map(*fs):
    """Returns a function that will apply every f_i for evey element of the tuple argument.

    Examples:
    ```pycon
    >>> inc = lambda x: x + 1
    >>> tuple_map(None, inc)((1, 2))
    (1, 3)
    >>> tuple_map(inc)((1, 2))
    (2, 2)
    >>>
    ```
    """

    return compose(
        tuple,
        fmap(
            tupled(lambda i, v: fs[i](v) if i < len(fs) and fs[i] else v),
        ),
        enumerate,
    )

tupled(func)

Returns a tupled version of the function.

Examples:

>>> tupled(lambda a, b: a + b)((2, 3))
5
>>>

Source code in compai/compai.py

def tupled(func):
    """Returns a tupled version of the function.

    Examples:
    ```pycon
    >>> tupled(lambda a, b: a + b)((2, 3))
    5
    >>>
    ```
    """

    @wraps(func)
    def _func(x):
        return func(*x)

    return _func