Functional utilities

pipe, curry, and retry are small helpers for function composition, partial application, and retrying asynchronous work.

fpstreams.functional

Function composition, staged argument binding, and asynchronous retries.

pipe

pipe(value: T, *functions: Callable[[Any], Any]) -> Any

Pass a value through a left-to-right sequence of callables.

Each callable receives the preceding callable's return value. With no callables, the original value is returned unchanged.

Parameters:

Name	Type	Description	Default
value	T	The first callable's input.	required
*functions	Callable[[Any], Any]	Unary callables to invoke in order.	()

Returns:

Type	Description
Any	The final callable's return value, or value when functions is empty.

curry

curry(function: Callable[..., T]) -> Callable[..., Any]

Wrap a callable so its arguments can be supplied across multiple calls.

The wrapped callable executes as soon as every non-variadic parameter without a default has been bound. Arguments may still be supplied all at once, and invalid or duplicate arguments raise the same binding errors produced by inspect.signature.

Parameters:

Name	Type	Description	Default
function	Callable[..., T]	A callable whose signature can be inspected.	required

Returns:

Type	Description
Callable[..., Any]	A wrapper that preserves function metadata. It calls function once all required arguments are bound; otherwise it returns a callable for the next arguments.

retry

retry(
    attempts: int = 3,
    backoff: float = 2.0,
    jitter: bool = True,
    exceptions: tuple[type[Exception], ...] = (Exception,),
    *,
    delay: float = 0.0,
) -> Callable[
    [Callable[P, Awaitable[T]]], Callable[P, Awaitable[T]]
]

Decorate an async callable with bounded retries and exponential delay.

attempts includes the initial call. Only exceptions are retried; all other exceptions propagate immediately. Before each retry, the current delay is optionally increased by a random value of up to ten percent, then multiplied by backoff for the next retry.

Parameters:

Name	Type	Description	Default
attempts	int	Maximum calls, including the initial call; must be at least one.	3
backoff	float	Non-negative multiplier applied after each retry delay.	2.0
jitter	bool	Whether to add up to ten percent random jitter to nonzero delays.	True
exceptions	tuple[type[Exception], ...]	Exception classes that trigger another attempt.	(Exception,)
delay	float	Non-negative seconds to wait before the first retry.	0.0

Returns:

Type	Description
Callable[[Callable[P, Awaitable[T]]], Callable[P, Awaitable[T]]]	A decorator whose wrapper retries the asynchronous callable under this policy.

Raises:

Type	Description
ValueError	If attempts is less than one or a delay parameter is negative.