ParseListExpression.re

and parseInt = (p: Parser.t) => {
  let res =
    switch (p.token) {
    | Int(n) => n
    | _ =>
      Parser.err(p, "integer expected");
      (-1);
    };
  Parser.next(p);
  res;
}


// Annotating parseList is an error: can't be analyzed directly as it takes a parameter f
[@progress]
and parseList: 'a. (Parser.t, ~f: Parser.t => 'a) => list('a) =
  (p: Parser.t, ~f) =>
    if (p.token == Asterisk) {
      [];
    } else {
      let item = f(p);
      let l = parseList(p, ~f);
      [item, ...l];
    }

[@progress]
and parseExpression = (p: Parser.t) => {
  switch (p.token) {
  | Lparen =>
    Parser.next(p);
    let e1 = parseExpression(p);
    Parser.expect(p, Plus);
    let e2 = parseExpression(p);
    Parser.expect(p, Lparen);
    Expr.Plus(e1, e2);
  | _ => Expr.Int(parseInt(p))
  };
}

[@progress]
and parseListExpression = p => parseList(p, ~f=parseExpression);