[sledge] Add Term.get_trm

Reviewed By: da319

Differential Revision: D24532342

fbshipit-source-id: 4c257ff41

sledge/src/fol.ml

@@ -275,6 +275,8 @@ module Term = struct
     | `Trm (Q q) -> Some q
     | _ -> None
 
+  let get_trm = function `Trm t -> Some t | _ -> None
+
   (** Access *)
 
   let split_const e =

sledge/src/fol.mli

@@ -58,6 +58,8 @@ module rec Term : sig
   val get_const : t -> Q.t option
   (** [get_const a] is [Some q] iff [equal a (const q)] *)
 
+  val get_trm : t -> Trm.t option
+
   (** Access *)
 
   val split_const : t -> t * Q.t