moonsugar v0.1.2 Moonsugar.Maybe
The Maybe module contains functions that help create and interact with the maybe type. The Maybe type is represented as either {:just, value} or :nothing.
Link to this section Summary
Functions
Like map, but chain takes a function that returns a maybe type. This prevents nested maybes
Converts a variable that might be nil to a maybe type
Converts a variable from a result type to a maybe type
Converts a variable from a validation type to a maybe type
Extracts a value from a maybe type. If the provided argument doesn’t have a value, the default is returned
Determines if a value is a maybe type
Helper function to create a just tuple
Maps over a maybe type
Helper function to create a nothing value
Link to this section Functions
Like map, but chain takes a function that returns a maybe type. This prevents nested maybes.
Examples
iex> Maybe.map({:just, 3}, fn(x) ->
...> cond do
...> x > 0 -> {:just, x * 3}
...> x <= 0 -> :nothing
...> end
...> end)
{:just, {:just, 9}}
iex> Maybe.chain({:just, 3}, fn(x) ->
...> cond do
...> x > 0 -> {:just, x * 3}
...> x <= 0 -> :nothing
...> end
...> end)
{:just, 9}
iex> Maybe.chain({:just, 0}, fn(x) ->
...> cond do
...> x > 0 -> {:just, x * 3}
...> x <= 0 -> :nothing
...> end
...> end)
:nothingConverts a variable that might be nil to a maybe type.
Examples
iex> Maybe.from_nilable("khajiit has wares")
{:just, "khajiit has wares"}
iex> Maybe.from_nilable(nil)
:nothingConverts a variable from a result type to a maybe type.
Examples
iex> Maybe.from_result({:ok, 3})
{:just, 3}
iex> Maybe.from_result({:error, "I took an arrow to the knee"})
:nothingConverts a variable from a validation type to a maybe type.
Examples
iex> Maybe.from_validation({:success, "Dragon Slayed"})
{:just, "Dragon Slayed"}
iex> Maybe.from_result({:fail, ["You Died"]})
:nothingExtracts a value from a maybe type. If the provided argument doesn’t have a value, the default is returned.
Examples
iex> Maybe.get_with_default({:just, 3}, 0)
3
iex> Maybe.get_with_default(:nothing, 0)
0Determines if a value is a maybe type.
Examples
iex> Maybe.is_maybe({:just, 0})
true
iex> Maybe.is_maybe(:nothing)
true
iex> Maybe.is_maybe({:ok, 3})
falseHelper function to create a just tuple.
Examples
iex> Maybe.just(3)
{:just, 3}Maps over a maybe type.
Examples
iex> Maybe.map({:just, 3}, fn(x) -> x * 2 end)
{:just, 6}
iex> Maybe.map(:nothing, fn(x) -> x * 2 end)
:nothingHelper function to create a nothing value
Examples
iex> Maybe.nothing()
:nothing