Hike.Either (hike v0.0.1)

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Types

binder() represent a binding(mapping) function which take no parameter and return an Either of type <TR>.

binder(t) represent a binding(mapping) function which take a parameter of type <T> and return an Either of type <TR>.

represent a type of Either that could be in either Left or Right state

represent a type of Either that could be in either Left or Right state with a value of given type.

represent a type of Either in Left state.

represent a type of Either in Left state.

Elevated data type of Either struct that represents Right state.

Elevated data type of Either struct that represents Right state and have a value of type <T>.

func() represent a function which take no parameter and return value of type <TR>.

func(t) represent a function which take a parameter of type <T> and return a value of type <TR>.

mapper() represent a mapping function which take no parameter and return a value of type <TR>.

mapper(t) represent a mapping function which take a parameter of type <T> and return a value of type <TR>.

t()

generic input type <T>.

generic input type <T_Left> represent a type of value on Leftstate.

generic input type <T_Right>represent a type of value on Rightstate.

generic return type <TR>.

Functions

%Hike.Either{l_value: t_left(), r_value: t_right(), is_left?:boolean()} is a struct that represents an "either/or" value. It can contain either a left value or a right value, but not both.

apply_left applies a given function to a given Either if Either is in left state and return a new Either with new transformed value in Left state else return new Either in Right state with existing right value.

apply_right applies a given function to a given Either if Either is in right state and return a new Either with new transformed value in Right state else return new Either in Left state with existing left value.

Binds a function that returns an Either value for an Either in the left state. If the input Either is in the right state, the function is not executed and the input Either is returned as is.

Binds a function that returns an Either value to an Either in the right state. If the input Either is in the left state, the function is not executed and the input Either is returned as is.

Create new Either from result. if result is {:ok, val} Either will be in right state. else if result is {:error, val} Either will be in left state. with respective value val in respective side.

Check whether aneither is in Left state or not .

Check whether aneither is in Right state or not .

Creates a new Left Either object with a given value for the left side.

Maps the value of the Either from left state using the given function.

Maps the value of theEither from right state using the given function.

Matches an Either value and applies the corresponding function.

Creates a new Either in Right state with a given value.

Link to this section Types

@type binder() :: (() -> either_left(tr()) | either_right(tr()))

binder() represent a binding(mapping) function which take no parameter and return an Either of type <TR>.

example

Example

iex> right_bind_func = fn () -> Either.right(:ok) end
iex> left_bind_func = fn () -> Either.left(:ok) end
@type binder(t) :: (t -> either_left(tr()) | either_right(tr()))

binder(t) represent a binding(mapping) function which take a parameter of type <T> and return an Either of type <TR>.

example

Example

iex> right_bind_func = fn (x) -> Either.right(x) end
iex> left_bind_func = fn (y) -> Either.left(y) end
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either()

(opaque)
@opaque either()

represent a type of Either that could be in either Left or Right state

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either(t_left, t_right)

@type either(t_left, t_right) :: %Hike.Either{
  is_left?: boolean(),
  l_value: t_left,
  r_value: t_right
}

represent a type of Either that could be in either Left or Right state with a value of given type.

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either_left()

@type either_left() :: %Hike.Either{is_left?: true, l_value: t_left(), r_value: nil}

represent a type of Either in Left state.

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either_left(t)

@type either_left(t) :: %Hike.Either{is_left?: true, l_value: t, r_value: nil}

represent a type of Either in Left state.

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either_right()

@type either_right() :: %Hike.Either{
  is_left?: false,
  l_value: nil,
  r_value: t_right()
}

Elevated data type of Either struct that represents Right state.

Link to this type

either_right(t)

@type either_right(t) :: %Hike.Either{is_left?: false, l_value: nil, r_value: t}

Elevated data type of Either struct that represents Right state and have a value of type <T>.

@type func() :: (() -> tr())

func() represent a function which take no parameter and return value of type <TR>.

@type func(t) :: (t -> tr())

func(t) represent a function which take a parameter of type <T> and return a value of type <TR>.

@type mapper() :: (() -> tr())

mapper() represent a mapping function which take no parameter and return a value of type <TR>.

@type mapper(t) :: (t -> tr())

mapper(t) represent a mapping function which take a parameter of type <T> and return a value of type <TR>.

@type t() :: any()

generic input type <T>.

@type t_left() :: any()

generic input type <T_Left> represent a type of value on Leftstate.

@type t_right() :: any()

generic input type <T_Right>represent a type of value on Rightstate.

@type tr() :: any()

generic return type <TR>.

Link to this section Functions

Link to this function

%Hike.Either{}

(struct)

%Hike.Either{l_value: t_left(), r_value: t_right(), is_left?:boolean()} is a struct that represents an "either/or" value. It can contain either a left value or a right value, but not both.

  • l_value: the left value (if is_left? is true)
  • r_value: the right value (if is_left? is false)
  • is_left?: a boolean flag indicating whether the value is a left value (true) or a right value (false)
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apply_left(either, func)

@spec apply_left(either_left(t_left()), (t_left() -> tr())) :: either_left(tr())
@spec apply_left(either_right(t_right()), (t_left() -> tr())) ::
  either_right(t_right())

apply_left applies a given function to a given Either if Either is in left state and return a new Either with new transformed value in Left state else return new Either in Right state with existing right value.

examples

Examples

iex> (Either.left 5) |> Either.apply_left(fn num -> num + num end)
%Hike.Either{l_value: 10, r_value: nil, is_left?: true}

iex> (Either.right 5) |> Either.apply_left(fn num -> num + num end)
%Hike.Either{l_value: nil, r_value: 5, is_left?: false}
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apply_right(either, func)

@spec apply_right(either_left(t_left()), (t_right() -> tr())) :: either_left(t_left())
@spec apply_right(either_right(t_right()), (t_right() -> tr())) :: either_right(tr())

apply_right applies a given function to a given Either if Either is in right state and return a new Either with new transformed value in Right state else return new Either in Left state with existing left value.

examples

Examples

iex> (Either.right "hello") |> Either.apply_right(fn str -> String.upcase(str) end)
%Hike.Either{l_value: nil, r_value: "HELLO", is_left?: false}

iex> (Either.left "hello") |> Either.apply_right(fn str -> String.upcase(str) end)
%Hike.Either{l_value: "hello", r_value: nil, is_left?: true}
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bind_left(either, func)

@spec bind_left(either_left(t_left()), binder(t_left())) ::
  either_left(tr()) | either_right(tr())
@spec bind_left(either_right(t_right()), binder(t_left())) :: either_right(t_right())

Binds a function that returns an Either value for an Either in the left state. If the input Either is in the right state, the function is not executed and the input Either is returned as is.

examples

Examples

iex> (Either.left "hello") |> Either.bind_left(fn str -> Either.left(String.upcase(str)) end)
%Hike.Either{l_value: "HELLO", r_value: nil, is_left?: true}

iex> (Either.left "hello") |> Either.bind_left(fn str -> Either.right(String.upcase(str)) end)
%Hike.Either{l_value: nil, r_value: "HELLO", is_left?: false}

iex> (Either.right "hello") |> Either.bind_left(fn str -> Either.left(String.upcase(str)) end)
%Hike.Either{l_value: nil, r_value: "hello", is_left?: false}
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bind_right(either, func)

@spec bind_right(either_right(t_right()), binder(t_right())) ::
  either_right(tr()) | either_left(tr())
@spec bind_right(either_left(t_left()), binder(t_right())) :: either_left(t_left())

Binds a function that returns an Either value to an Either in the right state. If the input Either is in the left state, the function is not executed and the input Either is returned as is.

examples

Examples

iex> (Either.right "hello") |> Either.bind_right(fn str -> Either.right(String.upcase(str)) end)
%Hike.Either{l_value: nil, r_value: "HELLO", is_left?: false}

iex> (Either.right "hello") |> Either.bind_right(fn str -> Either.left(String.upcase(str)) end)
%Hike.Either{l_value: "HELLO", r_value: nil, is_left?: true}

iex> (Either.left "hello") |> Either.bind_right(fn str -> Either.right(String.upcase(str)) end)
%Hike.Either{l_value: "hello", r_value: nil, is_left?: true}
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from_result(arg)

@spec from_result({:ok, t()}) :: either_right(t())
@spec from_result({:error, t()}) :: either_left(t())

Create new Either from result. if result is {:ok, val} Either will be in right state. else if result is {:error, val} Either will be in left state. with respective value val in respective side.

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is_left?(either)

@spec is_left?(either()) :: boolean()

Check whether aneither is in Left state or not .

examples

Examples

iex> right("foo bar") |> Either.is_left?()
 false
iex> left("foo bar") |> Either.is_left?()
 true
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is_not_nil(value)

(macro)
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is_right?(either)

@spec is_right?(either()) :: boolean()

Check whether aneither is in Right state or not .

examples

Examples

iex> right("foo bar") |> Either.is_right?()
 true
iex> left("foo bar") |> Either.is_right?()
 false
@spec left(t_left()) :: either_left(t_left())

Creates a new Left Either object with a given value for the left side.

examples

Examples

iex> left("foo bar")
%Hike.Either{l_value: "foo bar", r_value: nil, is_left?: true}
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map_left(e, func)

@spec map_left(either_left(t_left()), (t_left() -> tr())) :: either_left(tr())
@spec map_left(either_right(t_right()), (t_left() -> tr())) :: either_right(t_right())

Maps the value of the Either from left state using the given function.

If the Either is in the right state, the function returns the Either unchanged. If the Either is in the left state, the function applies the given function to the value of the left state, and returns a new Either with the transformed value.

examples

Examples

iex> (Either.left 5) |> Either.map_left(fn num -> num + num end)
%Hike.Either{l_value: 10, r_value: nil, is_left?: true}

iex> (Either.right 5) |> Either.map_left(fn num -> num + num end)
%Hike.Either{l_value: nil, r_value: 5, is_left?: false}

iex> either = %Either{l_value: "hello", is_left?: true}
iex> new_either = Either.map_left(either, &String.upcase/1)
%Hike.Either{l_value: "HELLO", is_left?: true}

iex> either = %Either{r_value: 10, is_left?: false}
iex> new_either = Either.map_left(either, &String.downcase/1)
%Hike.Either{r_value: 10, is_left?: false}
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map_right(either, func)

@spec map_right(either_right(t_right()), (t_right() -> tr())) :: either_right(tr())
@spec map_right(either_left(t_left()), (t_right() -> tr())) :: either_left(t_left())

Maps the value of theEither from right state using the given function.

If the Either is in the left state, the function returns the Either unchanged. If the Either is in the right state, the function applies the given function to the value of the right state, and returns a new Either with the transformed value.

examples

Examples

iex> (Either.right "hello") |> Either.map_right(fn str -> String.upcase(str) end)
%Hike.Either{l_value: nil, r_value: "HELLO", is_left?: false}

iex> (Either.left "hello") |> Either.map_right(fn str -> String.upcase(str) end)
%Hike.Either{l_value: "hello", r_value: nil, is_left?: true}
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match(either, left_fn, right_fn)

@spec match(either(t_left(), t_right()), (t_left() -> tr()), (t_right() -> tr())) ::
  tr()

Matches an Either value and applies the corresponding function.

examples

Examples

 iex> (Either.left "hello") |> Either.match(fn str -> String.upcase(str) end, fn ()-> "NOT FOUND" end)
 "HELLO"
 iex> (Either.right 4) |> Either.match(fn num-> num * num end, fn num-> num + num end)
 8
@spec right(t_right()) :: either_right(t_right())

Creates a new Either in Right state with a given value.

examples

Examples

iex> right("foo bar")
%Hike.Either{l_value: nil, r_value: "foo bar", is_left?: false}