Reason BST Blog Post remove

ReasonBSTRemove.re

let rec remove = (tree, compare, v) =>
  switch (tree) {
  | Empty => Empty
  | Node({value, left: Empty, right: Empty}) =>
    compare(v, value) == 0 ? Empty : tree
  | Node({value, left: Node(_) as left, right: Empty as right}) =>
    compare(v, value) == 0 ?
      left : Node({value, left: remove(left, compare, v), right})
  | Node({value, left: Empty as left, right: Node(_) as right}) =>
    compare(v, value) == 0 ?
      right : Node({value, left, right: remove(right, compare, v)})
  | Node({value, left: Node(_) as left, right: Node(_) as right}) =>
    if (compare(v, value) == (-1)) {
      Node({value, left: remove(left, compare, v), right});
    } else if (compare(v, value) == 1) {
      Node({value, left, right: remove(right, compare, v)});
    } else {
      switch (min(right)) {
      | Empty => tree
      | Node(a) =>
        Node({value: a.value, left, right: remove(right, compare, a.value)})
      };
    }
  };