@spec apply(option(t()), func(t())) :: option(tr())

@spec apply(option(), func() | func(t())) :: option()

Applies a given function to the value of an Option struct and returns the result as a new Option. OR Applies a given function stored in an option to the value of another option, and returns the result as a new option.

examples

Examples

iex> option = %Option{value: 42}
iex> add_one = fn x -> x + 1 end
iex> Option.apply(option, add_one)
%Option{value: 43}

iex> none_option = %Option{value: nil}
iex> Option.apply(none_option, add_one)
%Option{value: nil}

iex> option = %Option{value: "hello"}
iex> upcase_string = fn str -> String.upcase(str) end
iex> Option.apply(option, upcase_string)
%Option{value: "HELLO"}

@spec bind(option(t()), binder(t())) :: option(tr())

@spec bind(option(), binder() | binder(t())) :: option()

Transforms an Option<T> struct with a non-nil value using a binder function that returns another Option<TR> struct.

If the input Option has a nil value, returns a new Option struct with a nil value. if you have a function that return Option<TR> and you want to apply mapping then use bind function to avoid double elevation.

examples

Examples

iex> option = %Option{value: 42}
iex> add_one = fn x -> Option.some(x + 1) end
iex> Option.bind(option, add_one)
%Option{value: 43}

iex> Option.bind(Option.some("hello"), fn x -> Option.some(String.upcase(x)) end)
%Option{value: "HELLO"}

iex> Option.bind(Option.none() )
%Option{value: nil}

@spec filter(option(), func()) :: option()

@spec filter(option(t()), func(t())) :: option(tr())

Applies the given function to the value of the provided option, returning a new option containing the original value if the function returns a truthy value, otherwise returning an empty option. If the provided option has no value, this function simply returns the empty option.

examples

Examples

iex> Option.filter(%Option{value: 42}, fn x -> rem(x, 2) == 0 end)
%Option{value: 42}

iex> Option.filter(%Option{value: 42}, fn x -> rem(x, 2) == 1 end)
%Option{value: nil}

iex> Option.filter(%Option{value: nil}, fn x -> rem(x, 2) == 0 end)
%Option{value: nil}

iex> list_opt = Option.some([1,2,3])
iex> list_filter = fn (lst) -> Enum.count(lst) > 5  end
iex> Option.filter(list_opt, list_filter)
%Hike.Option{value: nil}

@spec is_none?(option() | option(t())) :: boolean()

Returns true if the Option is in None state, otherwise false.

examples

Examples

iex> Option.is_none?(Option.none())
true

iex> Option.is_none?(Option.some("hello"))
false

@spec is_some?(option() | option(t())) :: boolean()

Returns true if the Option is in Some state, otherwise false.

examples

Examples

iex> Option.is_some?(Option.some("hello"))
true

iex> Option.is_some?(Option.none())
false

@spec map(option(t()), mapper(t())) :: option(tr())

@spec map(option(), mapper() | mapper(t())) :: option()

Applies the given mapping function to the value inside the Option struct and returns a new Option struct containing the transformed value. If the input Option struct is @none, the function returns a new Option struct in none state. ## Examples

  iex> Option.map(Option.some("hello"), fn x -> String.upcase(x) end)
  %Option{value: "HELLO"}

  iex> Option.map(Option.none(), fn x -> String.upcase(x) end)
  %Option{value: nil}

@spec match(option(), func()) :: tr()

@spec match(option(t()), func(t())) :: tr()

Matches on an option and returns the result of the matching function. Calls some_fun with the value of the Option if the Option is in :some state, or calls none_fun if the Option is in :none state.

examples

Examples

iex> import Hike.Option

# Match on `some` value with a matching function
iex> match(some(10), &(&1 * 2))
# => 20

# Match on `none` value with a none-matching function
iex> match(none(), fn -> "no value" end)
# => "no value"

# Match on `some` value with a matching function and on `none` value with a none-matching function
iex> match(some("hello"), &(&1 <> " world"), fn -> "no value" end)
# => "hello world"

# Match on `none` value with a none-matching function even if a matching function is provided
iex> match(none(), &(&1 * 2), fn -> "no value" end)
# => "no value"

iex> Option.match(Option.some("hello"), fn x -> String.upcase(x) end)
"HELLO"

iex> Option.match(Option.none(),  fn -> "nothing" end)
"nothing"

iex> Option.match(Option.some("hello"), fn x -> String.upcase(x) end, fn -> "nothing" end )
"HELLO"

iex> Option.match(Option.none(), fn x -> String.upcase(x) end,   fn -> "nothing" end)
"nothing"

@spec none() :: option()

Creates an Option in None state.

examples

Examples

iex> Option.none()
%Option{value: :nil}

@spec some(t()) :: option(t())

Creates an Option in Some state

examples

Examples

iex> Option.some("hello")
%Option{value: "hello"}