From b9965ca70908f8917d7ab84ab3c268f7095f5098 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Fri, 1 Nov 2019 15:11:09 -0500
Subject: [PATCH] feat(th-cstor): reimplement the theory

---
 src/th-cstor/Sidekick_th_cstor.ml | 81 ++++++++++++++++++-------------
 1 file changed, 47 insertions(+), 34 deletions(-)

diff --git a/src/th-cstor/Sidekick_th_cstor.ml b/src/th-cstor/Sidekick_th_cstor.ml
index ec70649e..2235fb29 100644
--- a/src/th-cstor/Sidekick_th_cstor.ml
+++ b/src/th-cstor/Sidekick_th_cstor.ml
@@ -27,54 +27,67 @@ module Make(A : ARG) : S with module A = A = struct
   type cstor_repr = {
     t: T.t;
     n: N.t;
+    cstor: Fun.t;
+    args: T.t list;
   }
   (* associate to each class a unique constructor term in the class (if any) *)
 
-  (* TODO 
   module N_tbl = Backtrackable_tbl.Make(N)
-     *)
-  module N_tbl = CCHashtbl.Make(N)
 
   type t = {
-    cstors: T.t N_tbl.t; (* repr -> cstor for the class *)
-    (* TODO: also allocate a bit in CC to filter out quickly classes without cstors *)
+    cstors: cstor_repr N_tbl.t; (* repr -> cstor for the class *)
+    (* TODO: also allocate a bit in CC to filter out quickly classes without cstors? *)
   }
 
-  let on_pre_merge (solver:SI.t) _cc acts n1 tc1 n2 tc2 e_n1_n2 : unit =
-    Log.debugf 5
-      (fun k->k "(@[th-cstor.on_pre_merge@ @[:c1 %a@ (term %a)@]@ @[:c2 %a@ (term %a)@]@])"
-          N.pp n1 T.pp tc1.t N.pp n2 T.pp tc2.t); 
-    let expl = Expl.mk_list [e_n1_n2; Expl.mk_merge n1 tc1.n; Expl.mk_merge n2 tc2.n] in
-    match A.view_as_cstor tc1.t, A.view_as_cstor tc2.t with
-    | T_cstor (f1, l1), T_cstor (f2, l2) ->
-      (* merging two constructor terms: injectivity + disjointness checks *)
-      if Fun.equal f1 f2 then (
-        (* same function: injectivity *)
-        assert (List.length l1 = List.length l2);
-        List.iter2
-          (fun u1 u2 -> SI.cc_merge_t solver acts u1 u2 expl)
-          l1 l2
-      ) else (
-        (* different function: disjointness *)
-        SI.cc_raise_conflict_expl solver acts expl
-      )
-    | _ -> assert false
+  let push_level self = N_tbl.push_level self.cstors
+  let pop_levels self n = N_tbl.pop_levels self.cstors n
 
   (* attach data to constructor terms *)
-  let on_new_term _ n (t:T.t) =
+  let on_new_term self _solver n (t:T.t) =
     match A.view_as_cstor t with
-    | T_cstor _ -> Some {t;n}
-    | _ -> None
+    | T_cstor (cstor,args) ->
+      N_tbl.add self.cstors n {n; t; cstor; args};
+    | _ -> ()
 
-  let create_and_setup (_solver:SI.t) : t =
+  let on_pre_merge (self:t) cc acts n1 n2 e_n1_n2 : unit =
+    begin match N_tbl.get self.cstors n1, N_tbl.get self.cstors n2 with
+      | Some cr1, Some cr2 ->
+        Log.debugf 5
+          (fun k->k "(@[th-cstor.on_pre_merge@ @[:c1 %a@ (term %a)@]@ @[:c2 %a@ (term %a)@]@])"
+              N.pp n1 T.pp cr1.t N.pp n2 T.pp cr2.t); 
+        (* build full explanation of why the constructor terms are equal *)
+        let expl =
+          Expl.mk_list [
+            e_n1_n2;
+            Expl.mk_merge n1 cr1.n;
+            Expl.mk_merge n2 cr2.n;
+          ]
+        in
+        if Fun.equal cr1.cstor cr2.cstor then (
+          (* same function: injectivity *)
+          assert (List.length cr1.args = List.length cr2.args);
+          List.iter2
+            (fun u1 u2 -> SI.CC.merge_t cc u1 u2 expl)
+            cr1.args cr2.args
+        ) else (
+          (* different function: disjointness *)
+          SI.CC.raise_conflict_from_expl cc acts expl
+      )
+      | None, Some cr ->
+        N_tbl.add self.cstors n1 cr
+      | Some _, None -> () (* already there on the left *)
+      | None, None -> ()
+    end
+
+  let create_and_setup (solver:SI.t) : t =
     let self = {
-      cstors=N_tbl.create 32;
+      cstors=N_tbl.create ~size:32 ();
     } in
-    (* TODO
-    SI.on_cc_pre_merge solver (on_pre_merge solver);
-    SI.on_cc_new_term solver on_new_term;
-       *)
+    Log.debug 1 "(setup :th-cstor)";
+    SI.on_cc_new_term solver (on_new_term self);
+    SI.on_cc_pre_merge solver (on_pre_merge self);
     self
 
-  let theory = A.S.mk_theory ~name ~create_and_setup ()
+  let theory =
+    A.S.mk_theory ~name ~push_level ~pop_levels ~create_and_setup ()
 end