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|
// TODO: all
// TODO: any
// TODO: at
// TODO: concat
// TODO: index_map
// TODO: intersperse
// TODO: sort
// TODO: unique
// TODO: zip
pub enum Empty =
| Empty
pub enum NotFound =
| NotFound
// Using the Erlang C BIF implementation.
//
pub external fn length(List(a)) -> Int = "erlang" "length"
// Using the Erlang C BIF implementation.
//
pub external fn reverse(List(a)) -> List(a) = "lists" "reverse"
pub fn is_empty(list) {
list == []
}
pub fn contains(list, elem) {
case list {
| [] -> False
| [head | rest] -> head == elem || contains(rest, elem)
}
}
pub fn head(list) {
case list {
| [] -> Error(Empty)
| [x | _] -> Ok(x)
}
}
pub fn tail(list) {
case list {
| [] -> Error(Empty)
| [_ | xs] -> Ok(xs)
}
}
fn do_filter(list, fun, acc) {
case list {
| [] -> reverse(acc)
| [x | xs] ->
let new_acc =
case fun(x) {
| True -> [x | acc]
| False -> acc
}
do_filter(xs, fun, new_acc)
}
}
pub fn filter(list, fun) {
do_filter(list, fun, [])
}
fn do_map(list, fun, acc) {
case list {
| [] -> reverse(acc)
| [x | xs] -> do_map(xs, fun, [fun(x) | acc])
}
}
pub fn map(list, fun) {
do_map(list, fun, [])
}
fn do_traverse(list, fun, acc) {
case list {
| [] -> Ok(reverse(acc))
| [x | xs] ->
case fun(x) {
| Ok(y) -> do_traverse(xs, fun, [y | acc])
| Error(error) -> Error(error)
}
}
}
pub fn traverse(list, fun) {
do_traverse(list, fun, [])
}
pub fn drop(list, n) {
case n <= 0 {
| True -> list
| False ->
case list {
| [] -> []
| [_ | xs] -> drop(xs, n - 1)
}
}
}
fn do_take(list, n, acc) {
case n <= 0 {
| True -> reverse(acc)
| False ->
case list {
| [] -> reverse(acc)
| [x | xs] -> do_take(xs, n - 1, [x | acc])
}
}
}
pub fn take(list, n) {
do_take(list, n, [])
}
pub fn new() {
[]
}
pub external fn append(List(a), List(a)) -> List(a) = "lists" "append";
fn do_flatten(lists, acc) {
case lists {
| [] -> acc
| [l | rest] -> do_flatten(rest, append(acc, l))
}
}
pub fn flatten(lists) {
do_flatten(lists, [])
}
pub fn fold(list, acc, fun) {
case list {
| [] -> acc
| [x | rest] -> fold(rest, fun(x, acc), fun)
}
}
pub fn fold_right(list, acc, fun) {
case list {
| [] -> acc
| [x | rest] -> fun(x, fold_right(rest, acc, fun))
}
}
pub fn find(haystack, f) {
case haystack {
| [] -> Error(NotFound)
| [x | rest] ->
case f(x) {
| Ok(x) -> Ok(x)
| _ -> find(rest, f)
}
}
}
pub fn all(list, f) {
case list {
| [] -> True
| [x | rest] ->
case f(x) {
| True -> all(rest, f)
| _ -> False
}
}
}
|
