rectify - v1.0.0

rectify/option

Option utilities for Rectify

Additional helpers for Gleam’s Option type that complement the standard library.

Values

choose_somes

</> 
pub fn choose_somes(opts: List(option.Option(a))) -> List(a)

Extract all Some values from a list of options.

Examples

choose_somes([Some(1), None, Some(2), None, Some(3)])
// -> [1, 2, 3]

default_to

</> 
pub fn default_to(opt: option.Option(a), default: a) -> a

Get the value from an option or return a default.

Examples

default_to(Some(42), 0)
// -> 42

default_to(None, 0)
// -> 0

default_with

</> 
pub fn default_with(opt: option.Option(a), f: fn() -> a) -> a

Get the value from an option or compute a default.

Examples

default_with(Some(42), fn() { 0 })
// -> 42

default_with(None, fn() { expensive_computation() })
// -> result of expensive_computation()

first_some

</> 
pub fn first_some(
  opts: List(option.Option(a)),
) -> option.Option(a)

Returns the first Some value, or None if all are None.

Examples

first_some([None, Some(2), Some(3)])
// -> Some(2)

first_some([None, None])
// -> None

is_none

</> 
pub fn is_none(opt: option.Option(a)) -> Bool

Check if an option is None.

Examples

is_none(None)
// -> True

is_none(Some(42))
// -> False

is_some

</> 
pub fn is_some(opt: option.Option(a)) -> Bool

Check if an option is Some.

Examples

is_some(Some(42))
// -> True

is_some(None)
// -> False

map2

</> 
pub fn map2(
  opt1: option.Option(a),
  opt2: option.Option(b),
  f: fn(a, b) -> c,
) -> option.Option(c)

Map over two options, returning None if either is None.

Examples

map2(Some(2), Some(3), fn(a, b) { a + b })
// -> Some(5)

map2(Some(2), None, fn(a, b) { a + b })
// -> None

map3

</> 
pub fn map3(
  opt1: option.Option(a),
  opt2: option.Option(b),
  opt3: option.Option(c),
  f: fn(a, b, c) -> d,
) -> option.Option(d)

Map over three options.

Examples

map3(Some(1), Some(2), Some(3), fn(a, b, c) { a + b + c })
// -> Some(6)

map3(Some(1), None, Some(3), fn(a, b, c) { a + b + c })
// -> None

map4

</> 
pub fn map4(
  opt1: option.Option(a),
  opt2: option.Option(b),
  opt3: option.Option(c),
  opt4: option.Option(d),
  f: fn(a, b, c, d) -> g,
) -> option.Option(g)

Map over four options.

Examples

map4(Some(1), Some(2), Some(3), Some(4), fn(a, b, c, d) { a + b + c + d })
// -> Some(10)

map4(Some(1), Some(2), None, Some(4), fn(a, b, c, d) { a + b + c + d })
// -> None

map5

</> 
pub fn map5(
  opt1: option.Option(a),
  opt2: option.Option(b),
  opt3: option.Option(c),
  opt4: option.Option(d),
  opt5: option.Option(e),
  f: fn(a, b, c, d, e) -> h,
) -> option.Option(h)

Map over five options.

Examples

map5(Some(1), Some(2), Some(3), Some(4), Some(5), fn(a, b, c, d, e) { a + b + c + d + e })
// -> Some(15)

map5(Some(1), None, Some(3), Some(4), Some(5), fn(a, b, c, d, e) { a + b + c + d + e })
// -> None

of_result

</> 
pub fn of_result(result: Result(a, e)) -> option.Option(a)

Convert a Result to an Option, discarding the error.

Examples

of_result(Ok(42))
// -> Some(42)

of_result(Error("oops"))
// -> None

to_result

</> 
pub fn to_result(opt: option.Option(a), error: e) -> Result(a, e)

Convert an Option to a Result with a custom error.

Examples

to_result(Some(42), "not found")
// -> Ok(42)

to_result(None, "not found")
// -> Error("not found")
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