Selection Sort in Haskell and Elixir

selection_sort.exs

defmodule SelectionSort do
  def sort(list), do: sort(list, [])
  def sort([], result), do: result
  def sort(list, result) do
    min = minimum(list)
    xs = delete(list, min)
    sort(xs, result ++ [min])
  end

  def minimum([head|tail]), do: minimum(tail, head)
  def minimum([], memo), do: memo
  def minimum([head|tail], memo) do
    minimum tail, (if head < memo, do: head, else: memo)
  end

  def delete(list, item), do: delete(list, item, [], true)
  def delete([], _, rest, _), do: rest
  def delete([head|tail], item, rest, flag) do
    if flag && (head == item) do
      delete(tail, item, rest, false)
    else
      delete(tail, item, rest ++ [head], flag)
    end
  end
end

SelectionSort.hs

module SelectionSort (sort) where

sort :: (Ord a, Num a) => [a] -> [a]
sort list = selectionSort' list []
  where
  selectionSort' [] result = result
  selectionSort' list result = selectionSort' tail' (result ++ [min])
    where
      min = minimum list
      tail' = delete list min
      minimum (head:tail) = minimum' tail head
      minimum' [] memo = memo
      minimum' (head:tail) memo = minimum' tail $ if head < memo then head else memo

delete :: (Num a, Eq a) => [a] -> a -> [a]
delete list item = delete' list item [] True
  where
  delete' [] item rest flag = rest
  delete' (head:tail) item rest flag =
    if flag && (head == item) then
      delete' tail item rest False
    else
      delete' tail item (rest ++ [head]) flag