diff --git a/minils/transformations/callgraph.ml b/minils/transformations/callgraph.ml
index b002d4b..603a76b 100644
--- a/minils/transformations/callgraph.ml
+++ b/minils/transformations/callgraph.ml
@@ -6,21 +6,7 @@ open Format
 open Location
 open Printf
 open Static
-
-module Error =
-struct
-  type error =
-    | Emain_node_no_params of name
-
-  let message loc kind =
-    begin match kind with
-      | Emain_node_no_params n ->
-          eprintf "%aThe main node '%s' cannot have parameters.\n"
-            output_location loc 
-	    n	  
-    end;
-    raise Misc.Error
-end
+open Signature
 
 let nodes_instances = ref NamesEnv.empty
 let global_env = ref NamesEnv.empty
@@ -32,7 +18,8 @@ let rec string_of_int_list = function
 
 let add_node_params n params =
   if NamesEnv.mem n !nodes_instances then 
-    nodes_instances := NamesEnv.add n (params::(NamesEnv.find n !nodes_instances)) !nodes_instances
+    nodes_instances := NamesEnv.add n 
+      (params::(NamesEnv.find n !nodes_instances)) !nodes_instances
   else
     nodes_instances := NamesEnv.add n [params] !nodes_instances
 
@@ -40,69 +27,75 @@ let rec node_by_name s = function
   | [] -> raise Not_found
   | n::l -> 
       if n.n_name = s then
-	n
+	      n
       else
-	node_by_name s l  
+	      node_by_name s l  
 
 let build env params_names params_values = 
-  List.fold_left2 (fun m n v -> NamesEnv.add n (SConst v) m) env params_names params_values
+  List.fold_left2 (fun m { p_name = n } v -> NamesEnv.add n (SConst v) m) 
+    env params_names params_values
 
 let rec collect_exp nodes env e =
   match e.e_desc with
     | Emerge(_, c_e_list) ->
-	List.iter (fun (_, e) -> collect_exp nodes env e) c_e_list
+	      List.iter (fun (_, e) -> collect_exp nodes env e) c_e_list
     | Eifthenelse(e1, e2, e3) ->
-	collect_exp nodes env e1;
-	collect_exp nodes env e2;
-	collect_exp nodes env e3
-    | Ewhen(e, _, _) | Efby(_, e) | Efield(e, _) | Erepeat (_,e) 
-    | Eselect (_,e) | Eselect_slice (_ , _, e) ->
-	collect_exp nodes env e
-    | Etuple e_list | Earray e_list 
-    | Eop(_, _, e_list)  ->
-	List.iter (collect_exp nodes env) e_list
-    | Evar _ | Econstvar _ | Econst _  | Ereset_mem _ -> ()
+	      collect_exp nodes env e1;
+	      collect_exp nodes env e2;
+	      collect_exp nodes env e3
+    | Ewhen(e, _, _) | Efby(_, e) | Efield(e, _) ->
+	      collect_exp nodes env e        
+    | Evar _ | Econstvar _ | Econst _ -> ()
     | Estruct(f_e_list) ->
-	List.iter (fun (_, e) -> collect_exp nodes env e) f_e_list
-    | Eselect_dyn (e_list, _, e1, e2) -> 
-	List.iter (collect_exp nodes env) e_list;
-	collect_exp nodes env e1;
-	collect_exp nodes env e2    
-    | Eupdate (_, e1, e2) | Econcat (e1, e2) | Efield_update(_, e1, e2) ->
-	collect_exp nodes env e1;
-	collect_exp nodes env e2
+	      List.iter (fun (_, e) -> collect_exp nodes env e) f_e_list
+    | Etuple e_list | Earray e_list ->
+	      List.iter (collect_exp nodes env) e_list
+    | Efield_update(_, e1, e2) ->
+	      collect_exp nodes env e1;
+	      collect_exp nodes env e2
     (* Do the real work: call node *)
-    | Eevery(ln, params, e_list, _) 
-    | Eapp(ln, params, e_list) -> 
-	List.iter (collect_exp nodes env) e_list;
-	let params = List.map (int_of_size_exp env) params in 
-	  (match params with
-	     | [] -> ()
-	     | params -> 
-		 let n = node_by_name (shortname ln.a_op) nodes in
-		   node_call nodes n params
-	  )
-    | Eiterator (_, ln, params, _, e_list, _) ->
-	List.iter (collect_exp nodes env) e_list;
-	let params = List.map (int_of_size_exp env) params in 
-	  (match params with
-	     | [] -> ()
-	     | params -> 
-		 let n = node_by_name (shortname ln) nodes in
-		   node_call nodes n params
-	  )
+    | Ecall( { op_name = ln; op_params = params; op_kind = Eop }, e_list, _) -> 
+        List.iter (collect_exp nodes env) e_list
+    | Ecall( { op_name = ln; op_params = params; op_kind = Enode }, e_list, _) -> 
+	      List.iter (collect_exp nodes env) e_list;
+	      let params = List.map (int_of_size_exp env) params in 
+          call_node_instance nodes ln params
+    | Earray_op op ->
+        collect_array_exp nodes env op
+
+and collect_array_exp nodes env = function
+  | Eselect_dyn (e_list, _, e1, e2) -> 
+	    List.iter (collect_exp nodes env) e_list;
+	    collect_exp nodes env e1;
+	    collect_exp nodes env e2    
+  | Eupdate (_, e1, e2) | Econcat (e1, e2) ->
+	    collect_exp nodes env e1;
+	    collect_exp nodes env e2
+  | Eselect (_,e) | Eselect_slice (_ , _, e) | Erepeat (_,e)  ->
+	    collect_exp nodes env e
+  | Eiterator (_, { op_name = ln; op_params = params }, _, e_list, _) ->
+	    List.iter (collect_exp nodes env) e_list;
+	    let params = List.map (int_of_size_exp env) params in 
+        call_node_instance nodes ln params
 	    
 and collect_eqs nodes env eq = 
   collect_exp nodes env eq.eq_rhs
 
+and call_node_instance nodes ln params =
+	match params with
+	  | [] -> ()
+	  | params -> 
+		    let n = node_by_name (shortname ln) nodes in
+		      node_call nodes n params
+
 and node_call nodes n params =
   match params with
     | [] -> 
-	List.iter (collect_eqs nodes !global_env) n.n_equs
+	      List.iter (collect_eqs nodes !global_env) n.n_equs
     | params ->
-	add_node_params n.n_name params;
-	let env = build !global_env n.n_params params in
-	  List.iter (collect_eqs nodes env) n.n_equs
+	      add_node_params n.n_name params;
+	      let env = build !global_env n.n_params params in
+	        List.iter (collect_eqs nodes env) n.n_equs
 
 let node n =
   let inst = 
@@ -113,7 +106,9 @@ let node n =
     { n with n_params_instances = inst }
 
 let build_const_env cd_list =
-  List.fold_left (fun env cd -> NamesEnv.add cd.Minils.c_name cd.Minils.c_value env) NamesEnv.empty cd_list
+  List.fold_left (fun env cd -> NamesEnv.add 
+                    cd.Minils.c_name cd.Minils.c_value env) 
+    NamesEnv.empty cd_list
 
 let program p =
   let try_call_node n =
@@ -124,4 +119,4 @@ let program p =
     global_env := build_const_env p.p_consts;
     List.iter try_call_node p.p_nodes;
     { p with p_nodes = List.map node p.p_nodes }
-	  
+