6 app = [lexpr:"f" .r!(["(" .w? expr:"arg" .w? ")"])]
5 lexpr = {
  bin:"bin"
  ty
  fun
  ["$" .$:"var"]
  .$:"num"
}
4 fun = {
  "id":"id"
  "sin":"sin"
  "cos":"cos"
  "neg":"neg"
  "mul":"mul"
  "add":"add"
  "fst_par":"fst_par"
  "snd_par":"snd_par"
  "fst":"fst"
  "snd":"snd"
}
3 ty = {
  ["type(" .$:"type_n" ")"]
  "f64":"f64"
}
2 bin = ["(" {
    "fun":"fun"
    "lin_lam":"lin_lam"
    "lin_comp":"lin_comp"
    "lin":"lin_fun"
    "par":"par"
    "tup":"tup"
    "comp":"comp"
    "lam":"lam"
    "ty":"ty"
  } .w! expr:"a" .w! expr:"b" .w? ")"]
1 expr = {
  app:"app"
  lexpr
}
0 doc = [.w? expr:"expr" .w?]