| NumValue of string
| OptValue of value option
| ListValue of value list
+ | DisambiguationValue of (string option * Stdpp.location * string option * string option)
type value_type =
| TermType of int (* the level of the expected term *)
| NumType
| OptType of value_type
| ListType of value_type
+ | NoType
(** looked up value not found in environment *)
exception Value_not_found of string