algorithm

Monadic algorithms. More...

Concepts
concept	gimo::applicable_to
	Evaluates whether a Nullable type is compatible with the specific Algorithm.

Classes
class	gimo::BasicAlgorithm< Traits, Action >
	The basic building block for every monadic operation. More...

Functions
template<typename Action>
constexpr auto	gimo::and_then (Action &&action)
	Creates a pipeline step that applies a function returning a nullable type.
template<typename Action>
constexpr auto	gimo::or_else (Action &&action)
	Creates a pipeline step that handles the null/error case.
template<typename Action>
constexpr auto	gimo::transform (Action &&action)
	Creates a pipeline step that transforms the underlying value.
template<typename Action>
constexpr auto	gimo::transform_error (Action &&action)
	Creates a pipeline step that transforms the error of an expected-like type.

Detailed Description

Monadic algorithms.

Function Documentation

and_then()

template<typename Action>

auto gimo::and_then ( Action && action )

nodiscardconstexpr

Creates a pipeline step that applies a function returning a nullable type.

Template Parameters

Action

The action type.

Parameters

action

A unary operation.

Returns

A Pipeline step containing the and_then algorithm.

• On Value: Invokes the action with the underlying value of the input. The action must return a nullable type.
• On Null: Propagates the null (or error) state immediately (i.e., action is not executed).

Let T be the (possibly cv-qualified) reference to the value extracted from the input nullable. Action must be invocable with an argument of type T (or a type to which T is implicitly convertible), while the decayed return-type will become the resulting nullable-type.

See also

https://en.wikipedia.org/wiki/Monad_(functional_programming)

or_else()

template<typename Action>

auto gimo::or_else ( Action && action )

nodiscardconstexpr

Creates a pipeline step that handles the null/error case.

Template Parameters

Action

The action type.

Parameters

action

A nullary operation.

Returns

A Pipeline step containing the or_else algorithm.

• On Value: Propagates the value state immediately (i.e., action is not executed).
• On Null: Invokes the action. The action must return a nullable type.

  See also

  https://en.wikipedia.org/wiki/Monad_(functional_programming)

transform()

template<typename Action>

auto gimo::transform ( Action && action )

nodiscardconstexpr

Creates a pipeline step that transforms the underlying value.

Template Parameters

Action

The action type.

Parameters

action

A unary operation.

Returns

A Pipeline step containing the transform algorithm.

• On Value: Invokes the action with the underlying value of the input. The result of this invocation is wrapped into a new instance of the nullable container.
• On Null: Propagates the null (or error) state immediately (i.e., action is not executed).

Let T be the (possibly cv-qualified) reference to the value extracted from the input nullable. Action must be invocable with an argument of type T (or a type to which T is implicitly convertible), while the decayed return-type will become the value-type of the resulting nullable.

See also

https://en.wikipedia.org/wiki/Map_(higher-order_function)

Note

The nullable type must support value-type rebinding.

See also

gimo::traits::rebind_value

transform_error()

template<typename Action>

auto gimo::transform_error ( Action && action )

nodiscardconstexpr

Creates a pipeline step that transforms the error of an expected-like type.

Template Parameters

Action

The action type.

Parameters

action

A nullary operation.

Returns

A Pipeline step containing the or_else algorithm.

• On Value: Propagates the value state immediately (i.e., action is not executed).
• On Null: Invokes the action with the underlying error of the input. The result of this invocation is wrapped as an error into a new instance of the expected_like container.

Let T be the (possibly cv-qualified) reference to the error extracted from the input expected_like. Action must be invocable with an argument of type T (or a type to which T is implicitly convertible), while the decayed return-type will become the error-type of the resulting nullable.

See also

https://en.wikipedia.org/wiki/Monad_(functional_programming)

Note

The expected_like type must support error-type rebinding.

See also

gimo::traits::rebind_error