Cons[A: A]

A list with a head and a tail, where the tail can be empty.

class val Cons[A: A] is
  ReadSeq[val->A] box

Implements


Constructors

create

new val create(
  a: val->A,
  t: (Cons[A] val | Nil[A] val))
: Cons[A] val^

Parameters

  • a: val->A
  • t: (Cons[A] val | Nil[A] val)

Returns


Public Functions

size

Returns the size of the list.

fun box size()
: USize val

Returns


apply

Returns the i-th element of the list. Errors if the index is out of bounds.

fun box apply(
  i: USize val)
: val->A ?

Parameters

Returns

  • val->A ?

values

Returns an iterator over the elements of the list.

fun box values()
: Iterator[val->A] ref^

Returns


is_empty

Returns a Bool indicating if the list is empty.

fun box is_empty()
: Bool val

Returns


is_non_empty

Returns a Bool indicating if the list is non-empty.

fun box is_non_empty()
: Bool val

Returns


Returns the head of the list.

fun box head()
: val->A

Returns

  • val->A

tail

Returns the tail of the list.

fun box tail()
: (Cons[A] val | Nil[A] val)

Returns


reverse

Builds a new list by reversing the elements in the list.

fun val reverse()
: (Cons[A] val | Nil[A] val)

Returns


prepend

Builds a new list with an element added to the front of this list.

fun val prepend(
  a: val->A!)
: Cons[A] val

Parameters

  • a: val->A!

Returns


concat

Builds a new list that is the concatenation of this list and the provided list.

fun val concat(
  l: (Cons[A] val | Nil[A] val))
: (Cons[A] val | Nil[A] val)

Parameters

Returns


map[B: B]

Builds a new list by applying a function to every member of the list.

fun val map[B: B](
  f: {(val->A): val->B}[A, B] box)
: (Cons[B] val | Nil[B] val)

Parameters

  • f: {(val->A): val->B}[A, B] box

Returns


flat_map[B: B]

Builds a new list by applying a function to every member of the list and using the elements of the resulting lists.

fun val flat_map[B: B](
  f: {(val->A): List[B]}[A, B] box)
: (Cons[B] val | Nil[B] val)

Parameters

  • f: {(val->A): List[B]}[A, B] box

Returns


for_each

Applies the supplied function to every element of the list in order.

fun val for_each(
  f: {(val->A)}[A] box)
: None val

Parameters

  • f: {(val->A)}[A] box

Returns


filter

Builds a new list with those elements that satisfy a provided predicate.

fun val filter(
  f: {(val->A): Bool}[A] box)
: (Cons[A] val | Nil[A] val)

Parameters

  • f: {(val->A): Bool}[A] box

Returns


fold[B: B]

Folds the elements of the list using the supplied function.

fun val fold[B: B](
  f: {(B, val->A): B^}[A, B] box,
  acc: B)
: B

Parameters

  • f: {(B, val->A): B^}[A, B] box
  • acc: B

Returns

  • B

every

Returns true if every element satisfies the provided predicate, false otherwise.

fun val every(
  f: {(val->A): Bool}[A] box)
: Bool val

Parameters

  • f: {(val->A): Bool}[A] box

Returns


exists

Returns true if at least one element satisfies the provided predicate, false otherwise.

fun val exists(
  f: {(val->A): Bool}[A] box)
: Bool val

Parameters

  • f: {(val->A): Bool}[A] box

Returns


partition

Builds a pair of lists, the first of which is made up of the elements satisfying the supplied predicate and the second of which is made up of those that do not.

fun val partition(
  f: {(val->A): Bool}[A] box)
: ((Cons[A] val | Nil[A] val) , (Cons[A] val | Nil[A] val))

Parameters

  • f: {(val->A): Bool}[A] box

Returns


drop

Builds a list by dropping the first n elements.

fun val drop(
  n: USize val)
: (Cons[A] val | Nil[A] val)

Parameters

Returns


drop_while

Builds a list by dropping elements from the front of the list until one fails to satisfy the provided predicate.

fun val drop_while(
  f: {(val->A): Bool}[A] box)
: (Cons[A] val | Nil[A] val)

Parameters

  • f: {(val->A): Bool}[A] box

Returns


take

Builds a list of the first n elements.

fun val take(
  n: USize val)
: (Cons[A] val | Nil[A] val)

Parameters

Returns


take_while

Builds a list of elements satisfying the provided predicate until one does not.

fun val take_while(
  f: {(val->A): Bool}[A] box)
: (Cons[A] val | Nil[A] val)

Parameters

  • f: {(val->A): Bool}[A] box

Returns


Private Functions

_reverse

Private helper for reverse, recursively working on elements.

fun val _reverse(
  l: (Cons[A] val | Nil[A] val),
  acc: (Cons[A] val | Nil[A] val))
: (Cons[A] val | Nil[A] val)

Parameters

Returns


_concat

Private helper for concat that recursively builds the new list.

fun val _concat(
  l: (Cons[A] val | Nil[A] val),
  acc: (Cons[A] val | Nil[A] val))
: (Cons[A] val | Nil[A] val)

Parameters

Returns


_map[B: B]

Private helper for map, recursively applying function to elements.

fun box _map[B: B](
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A): val->B}[A, B] box,
  acc: (Cons[B] val | Nil[B] val))
: (Cons[B] val | Nil[B] val)

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A): val->B}[A, B] box
  • acc: (Cons[B] val | Nil[B] val)

Returns


_flat_map[B: B]

Private helper for flat_map, recursively working on elements.

fun box _flat_map[B: B](
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A): List[B]}[A, B] box,
  acc: (Cons[B] val | Nil[B] val))
: (Cons[B] val | Nil[B] val)

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A): List[B]}[A, B] box
  • acc: (Cons[B] val | Nil[B] val)

Returns


_rev_prepend[B: B]

Prepends l in reverse order onto target

fun tag _rev_prepend[B: B](
  l: (Cons[B] val | Nil[B] val),
  target: (Cons[B] val | Nil[B] val))
: (Cons[B] val | Nil[B] val)

Parameters

Returns


_for_each

Private helper for for_each, recursively working on elements.

fun box _for_each(
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A)}[A] box)
: None val

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A)}[A] box

Returns


_filter

Private helper for filter, recursively working on elements, keeping those that match the predicate and discarding those that don't.

fun box _filter(
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A): Bool}[A] box,
  acc: (Cons[A] val | Nil[A] val))
: (Cons[A] val | Nil[A] val)

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A): Bool}[A] box
  • acc: (Cons[A] val | Nil[A] val)

Returns


_fold[B: B]

Private helper for fold, recursively working on elements.

fun val _fold[B: B](
  l: (Cons[A] val | Nil[A] val),
  f: {(B, val->A): B^}[A, B] box,
  acc: B)
: B

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(B, val->A): B^}[A, B] box
  • acc: B

Returns

  • B

_every

Private helper for every, recursively testing predicate on elements, returning false immediately on an element that fails to satisfy the predicate.

fun box _every(
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A): Bool}[A] box)
: Bool val

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A): Bool}[A] box

Returns


_exists

Private helper for exists, recursively testing predicate on elements, returning true immediately on an element satisfying the predicate.

fun box _exists(
  l: (Cons[A] val | Nil[A] val),
  f: {(val->A): Bool}[A] box)
: Bool val

Parameters

  • l: (Cons[A] val | Nil[A] val)
  • f: {(val->A): Bool}[A] box

Returns