parsing NetKAT polcies and predicates
val pol_of_string : ?pos:Lexing.position ‑> string ‑> Syntax.policyval pred_of_string : ?pos:Lexing.position ‑> string ‑> Syntax.predval pol_of_file : string ‑> Syntax.policyval pred_of_file : string ‑> Syntax.predmodule Portless : sig ... end