MaybeMonad.re

let return = (a: 'a) : option('a) => Some(a);

let bind = (m: option('a), f: 'a => option('b)) : option('b) =>
  switch (m) {
  | None => None
  | Some(a) => f(a)
  };

let (>>=) = bind;

/* module Example = {
  open MaybeMonad;
  type xyz = {
    x: string,
    y: string,
    z: string,
  };
  type maybeXYZ =
    option(
      {
        .
        "x": option(string),
        "y": option(string),
        "z": option(string),
      },
    );
  let getXYZ = (maybe: maybeXYZ) : option(xyz) =>
    maybe
    >>= (
      condition =>
        condition##x
        >>= (
          xValue =>
            condition##y
            >>= (
              yValue =>
                condition##z
                >>= (zValue => Some({x: xValue, y: yValue, z: zValue}))
            )
        )
    );
}; */