Monadic algorithms.
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| concept | gimo::applicable_to |
| | Evaluates whether a Nullable type is compatible with the specific Algorithm.
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| template<typename Action> |
| constexpr auto | gimo::and_then (Action &&action) |
| | Creates a pipeline step that applies a function returning a nullable type.
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| template<typename Action> |
| constexpr auto | gimo::or_else (Action &&action) |
| | Creates a pipeline step that handles the null/error case.
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| template<typename Action> |
| constexpr auto | gimo::transform (Action &&action) |
| | Creates a pipeline step that transforms the underlying value.
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| template<typename Action> |
| constexpr auto | gimo::transform_error (Action &&action) |
| | Creates a pipeline step that transforms the error of an expected-like type.
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| template<std::invocable Action> |
| constexpr auto | gimo::value_or_else (Action &&action) |
| | Creates a terminating pipeline step that returns the contained value or invokes a fallback action if the nullable is null.
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| template<typename Alternative> |
| constexpr auto | gimo::value_or (Alternative &&alternative) |
| | Creates a terminating pipeline step that returns the contained value or a specified alternative if the nullable is null.
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◆ and_then()
template<typename Action>
| auto gimo::and_then |
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Action && | action | ) |
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nodiscardconstexpr |
Creates a pipeline step that applies a function returning a nullable type.
- Template Parameters
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- Parameters
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- 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 |
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Action && | action | ) |
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nodiscardconstexpr |
Creates a pipeline step that handles the null/error case.
- Template Parameters
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- Parameters
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| action | A nullary operation. |
- Returns
- A Pipeline step containing the or_else algorithm.
◆ transform()
template<typename Action>
| auto gimo::transform |
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Action && | action | ) |
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nodiscardconstexpr |
Creates a pipeline step that transforms the underlying value.
- Template Parameters
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- Parameters
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- 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 | ) |
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nodiscardconstexpr |
Creates a pipeline step that transforms the error of an expected-like type.
- Template Parameters
-
- Parameters
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| 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
◆ value_or()
template<typename Alternative>
| auto gimo::value_or |
( |
Alternative && | alternative | ) |
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nodiscardconstexpr |
Creates a terminating pipeline step that returns the contained value or a specified alternative if the nullable is null.
- Template Parameters
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| Alternative | The alternative value type. |
- Parameters
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| alternative | The alternative value to use if the nullable is null. |
- Returns
- A Pipeline step containing the value_or algorithm.
- On Value: Forwards the underlying value of the input.
- On Null: Returns the specified alternative converted to the nullable's value type.
Alternative must be convertible to the nullable's value type.
◆ value_or_else()
template<std::invocable Action>
| auto gimo::value_or_else |
( |
Action && | action | ) |
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nodiscardconstexpr |
Creates a terminating pipeline step that returns the contained value or invokes a fallback action if the nullable is null.
- Template Parameters
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| Action | The fallback action type. |
- Parameters
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| action | A nullary operation that produces an alternative value. |
- Returns
- A Pipeline step containing the value_or_else algorithm.
- On Value: Forwards the underlying value of the input.
- On Null: Invokes action and returns its result converted to the nullable's value type.
The action is invoked only if the input nullable does not contain a value. The return type of action must be convertible to the nullable's value type.
1.16.1