_sep: "()[]-=<>!"

4 plus = .r!({"=":"+2" "-":"+1"})
3 mor = [lexpr:"left" .w! {
  "<>":"zero"
  ["<":"right_inv" plus ">>"]
  ["<":"iso" plus ">"]
  [plus ">>":"epi"]
  ["<<":"rev_right_inv" plus ">"]
  ["<<":"rev_epi_mono" plus "!"]
  ["<<":"rev_epi" plus]
  [plus ">":"dir"]
  ["!" plus ">>":"epi_mono"]
  ["!" plus ">":"mono"]
  ["<" plus "!":"rev_mono"]
  ["<":"rev_dir" plus]
} .w! expr:"right"]
2 lexpr = {
  [{
    ["(" .w? expr .w? ")"]
    "0":"0"
    .._sep!:"obj"
  } ?["[" .w? expr:"path" .w? "]"]]
}
1 expr = {
  mor:"mor"
  lexpr
}
0 doc = [.w? expr:"expr" .w?]