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import gleam/pair
import gleam/iterator as iter
import gleam/result as res
import ext/iteratorx as iterx
pub fn count(list: List(a), satisfying predicate: fn(a) -> Bool) -> Int {
list
|> iter.from_list
|> iterx.count(satisfying: predicate)
}
fn set_helper(list: List(a), value: a, index: Int, counter: Int) -> List(a) {
case list {
[] -> []
[_, ..t] if counter == index -> [value, ..t]
[h, ..t] -> [h, ..set_helper(t, value, index, counter + 1)]
}
}
pub fn set(list: List(a), value: a, at index: Int) -> List(a) {
set_helper(list, value, index, 0)
}
pub fn index_of(list: List(a), value: a) -> Result(Int, Nil) {
list
|> iter.from_list
|> iter.index
|> iter.find(one_that: fn(elem) { pair.first(elem) == value })
|> res.map(with: pair.second)
}
|
