type 'a substitution = (int * 'a foterm) list
-type comparison = Lt | Le | Eq | Ge | Gt | Incomparable
+type comparison = Lt | Eq | Gt | Incomparable
type rule = SuperpositionRight | SuperpositionLeft | Demodulation
+
+(* A Discrimination tree is a map: foterm |-> (dir, clause) *)
type direction = Left2Right | Right2Left | Nodir
+
type position = int list
type 'a proof =
- | Exact of 'a
+ | Exact of 'a foterm
+ (* for theorems like T : \forall x. C[x] = D[x] the proof is
+ * a foterm like (Node [ Leaf T ; Var i ]), while for the Goal
+ * it is just (Var g), i.e. the identity proof *)
| Step of rule * int * int * direction * position * 'a substitution
(* rule, eq1, eq2, direction of eq2, position, substitution *)
module M : Map.S with type key = int
-type 'a bag = 'a unit_clause M.t
+type 'a bag = 'a unit_clause M.t
+
+module type Blob =
+ sig
+ (* Blob is the type for opaque leaves:
+ * - checking equlity should be efficient
+ * - atoms have to be equipped with a total order relation
+ *)
+ type t
+ val eq : t -> t -> bool
+ val compare : t -> t -> int
+ val eqP : t
+ (* TODO: consider taking in input an imperative buffer for Format
+ * val pp : Format.formatter -> t -> unit
+ * *)
+ val pp : t -> string
+
+ val embed : t -> t foterm
+ (* saturate [proof] [type] -> [proof] * [type] *)
+ val saturate : t -> t -> t foterm * t foterm
+ end