Reformat can't handle a file

[spike7638]

A student of mine wrote the attached code (which I've cleaned up a good deal to isolate the problem). He didn't realize that in an if-else expression returning a function, an INFIX function needs to be parenthesized, so he had this fragment:

let op = if (b) {<} else {>}

Once you put parens around the "<" and ">", everything's fine. Complete example appended here because I can't seem to attach a reasonML file.

===

type direction = L | R;
type path = list(direction);
type intTree = Leaf | Node(int, intTree, intTree);

let rec ammH: (intTree, list(direction), bool) => (path, int) =
  (inT, aloi, b) =>
  {
     let op = if (b) {<} else {>}

    switch (inT, aloi) {
    | (Leaf, _) => failwith("Tree cannot be empty")
    | (Node(x, Leaf, Leaf), direct) => (List.rev(direct), x)
    | (Node(_, Leaf, right), list) => ammH(right, [R, ...list], !b)
    | (Node(_, left, Leaf), list) => ammH(left, [L, ...list], !b)
    | (Node(_, Node(x1, x2, x3), Node(y1, y2, y3)), list) =>
      if ( op(x1, y1) ) {
        ammH(Node(x1, x2, x3), [L, ...list], !b);
      } else {
        ammH(Node(y1, y2, y3), [R, ...list], !b);
      }

    };
}

 let amm: intTree => (path, int) = intTree => ammH(intTree, [], false)