dataprep/non_empty_list

Types

NonEmptyList guarantees at least one element. Used by Invalid to ensure every failure carries at least one error.

pub type NonEmptyList(a) {
  NonEmptyList(first: a, rest: List(a))
}

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pub fn append(
  left left: NonEmptyList(a),
  right right: NonEmptyList(a),
) -> NonEmptyList(a)

Concatenate two NonEmptyLists.

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pub fn concat(
  lists: NonEmptyList(NonEmptyList(a)),
) -> NonEmptyList(a)

Flatten a NonEmptyList of NonEmptyLists into a single NonEmptyList.

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pub fn cons(
  head head: a,
  tail tail: NonEmptyList(a),
) -> NonEmptyList(a)

Prepend an element to a NonEmptyList.

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pub fn flat_map(
  nel: NonEmptyList(a),
  f: fn(a) -> NonEmptyList(b),
) -> NonEmptyList(b)

Map then flatten.

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pub fn from_list(l: List(a)) -> Result(NonEmptyList(a), Nil)

Try to create a NonEmptyList from a List. Returns Error(Nil) if the list is empty.

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pub fn map(
  nel: NonEmptyList(a),
  f: fn(a) -> b,
) -> NonEmptyList(b)

Transform every element.

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pub fn single(value: a) -> NonEmptyList(a)

Create a NonEmptyList with a single element.

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pub fn to_list(nel: NonEmptyList(a)) -> List(a)

Convert to a plain List.