Added a [lookup] method in every kit that needs it.

src/KitAvoid.ml

@@ -20,5 +20,6 @@ let extend bad x env =
 
 class ['self] map bad = object (_ : 'self)
   method private extend x env = extend bad x env
-  method private visit_'fn env x = lookup env x
+  method private lookup = lookup
+  method private visit_'fn = lookup
 end

src/KitCopy.ml

@@ -23,5 +23,6 @@ let extend x env =
 
 class ['self] map = object (_ : 'self)
   method private extend x env = extend x env
-  method private visit_'fn env x = lookup env x
+  method private lookup = lookup
+  method private visit_'fn = lookup
 end

src/KitEquiv.ml

@@ -48,5 +48,6 @@ let lookup (m1, m2, _) x1 x2 =
 
 class ['self] iter2 = object (_ : 'self)
   method private extend = extend
+  method private lookup = lookup
   method private visit_'fn = lookup
 end

src/KitExport.ml

@@ -51,5 +51,6 @@ let lookup env a =
 
 class ['self] map = object (_ : 'self)
   method private extend = extend
+  method private lookup = lookup
   method private visit_'fn = lookup
 end

src/KitImport.ml

@@ -28,5 +28,6 @@ let lookup (env : env) (x : string) : Atom.t =
 
 class ['self] map = object (_ : 'self)
   method private extend x env = extend x env
-  method private visit_'fn env x = lookup env x
+  method private lookup = lookup
+  method private visit_'fn = lookup
 end

src/KitShow.ml

@@ -2,7 +2,11 @@
 
 (* At an abstraction or at a name occurrence, [Atom.show] is applied. *)
 
+let lookup _env x =
+  Atom.show x
+
 class ['self] map = object (_ : 'self)
   method private extend x env = Atom.show x, env
-  method private visit_'fn _env x = Atom.show x
+  method private lookup = lookup
+  method private visit_'fn = lookup
 end

src/KitSubst.ml

@@ -17,8 +17,15 @@ let extend x env =
      substitution [env], unchanged, under the binder. *)
   x, env
 
+let lookup env x =
+  try
+    Atom.Map.find x env
+  with Not_found ->
+    assert false
+
 class ['self] map = object (_ : 'self)
   method private extend = extend
+  method private lookup = lookup
   (* [visit_'fn] must be implemented. There could be several kinds of
      nodes that carry variables of type ['fn], say, [FooVar] and [BarVar],
      and the user may decide to substitute away [FooVar] nodes, but leave

src/KitToDeBruijn.ml

@@ -45,6 +45,7 @@ end) = struct
 
   class ['self] map = object (_ : 'self)
     method private extend = extend
+    method private lookup _env _x = ()
     method private visit_'fn = lookup
   end
 

src/KitTrivial.ml

@@ -8,19 +8,3 @@ class ['self] iter = object (_ : 'self)
   method private extend _x env = env
   method private visit_'fn _env _x = ()
 end
-
-(* The following are presently unused:
-
-class ['self] map = object (_ : 'self)
-  method private extend x env = x, env
-  method private visit_'fn _env x = x
-end
-
-class virtual ['self] reduce = object (self : 'self)
-  method private virtual zero: _
-  method private extend _x env = env
-  method private restrict _x z = z
-  method private visit_'fn _env _x = self#zero
-end
-
- *)

src/ToolboxInput.ml

@@ -24,6 +24,7 @@ module type INPUT = sig
 
   class virtual ['self] map : object ('self)
     method private virtual extend : 'bn1 -> 'env -> 'bn2 * 'env
+    method private virtual lookup : 'env -> 'bn1 -> 'bn2
     method private virtual visit_'fn : 'env -> 'fn1 -> 'fn2
     method visit_term : 'env -> ('bn1, 'fn1) term -> ('bn2, 'fn2) term
     method private visit_TVar : 'env -> 'fn1 -> ('bn2, 'fn2) term