apfel.core.common

Common yet miscellaneous utilities functions.

API#

Functions

Name	Description
apply	Applies a single-argument function to a value.
identity	Returns the sole argument passed to it doing nothing.
imperative	Returns the last expression passed into the function.
not_none	Type narrowing: assert the value isn't None.
pipe	Pipes a value through a sequence of functions.
todo	Marks an unimplemented location that might be implemented in the future.
unimplemented	Marks an unimplemented location that might not be implemented in the future.

applyfunction#

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def apply(value: T, func: Callable[[T], R], /) -> R

Applies a single-argument function to a value. For chained calls, see pipe.

See also apply from Python 2.7.

This function is different from Value.apply, which is an implementation of Applicative who requires the function to be wrapped in Value. In contrast, this function accepts arbitrary callables.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Description
value	T	The value to be passed to the function.
func	Callable[[T], R]	The function to apply.

Returns

R

The result of applying the function to the value.

identityfunction#

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def identity(value: T, /) -> T

Returns the sole argument passed to it doing nothing.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Description
value	T	Any object.

Returns

T

The same object passed to it.

imperativefunction#

View source

def imperative(*exprs: *tuple[*Ts, R]) -> R

Returns the last expression passed into the function. If no expression are passed, returns None, per Python’s convention.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Default	Description
*exprs	*tuple[*Ts, R]	()	Any number of expressions.

Returns

R

The last expression passed into the function.

not_nonefunction#

View source

def not_none(value: T | None, /) -> T

Type narrowing: assert the value isn’t None.

This function is exposed in the package namespace.

Parameters

Name	Type	Description
value	T	Any value that type-checked to be None, but guarantees to be non-None.

Returns

T

The same value passed to it.

Raises

ValueError

if the input is actually None.

pipefunction#

View source

def pipe(value: T | Any, /, *funcs: Callable[[T], T] | *tuple[*tuple[Callable[[Any], Any], ...], Callable[[Any], R]] | Callable[[Any], Any]) -> T | T1 | T2 | T3 | T4 | R | Any

Pipes a value through a sequence of functions. For single function application, see apply.

See also Value.update, FunctionObject.__rand__. See also &, |> or roughly %>%.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Default	Description
value	T	required	The initial value to be piped.
*funcs	Callable[[Any], Any]	()	A sequence of functions to apply to the value.

Returns

AnyT | T1 | T2 | T3 | T4 | R | Any

The final result after applying all functions.

todofunction#

View source

def todo(message: str | None = None, /) -> NoReturn

Marks an unimplemented location that might be implemented in the future. See todo! for usage.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Default	Description
message	str | None	None	The extra message to be displayed.

Raises

NotImplementedError

Always.

unimplementedfunction#

View source

def unimplemented(message: str | None = None, /) -> NoReturn

Marks an unimplemented location that might not be implemented in the future. See unimplemented! for usage.

This function is exposed in the package namespace and the builtins namespace.

Parameters

Name	Type	Default	Description
message	str | None	None	The extra message to be displayed.

Raises

NotImplementedError

Always.