4 files changed, 35 insertions, 22 deletions

diff --git a/lib/syntax/S.ml b/lib/syntax/S.ml
index 918d8e6..a3c74ca 100644
--- a/lib/syntax/S.ml
+++ b/lib/syntax/S.ml
@@ -8,11 +8,20 @@
 
 (** {1 Generic types used in the module} *)
 
-type pos = Lexing.position * Lexing.position
+type position = Lexing.position = {
+  pos_fname : string;
+  pos_lnum : int;
+  pos_bol : int;
+  pos_cnum : int;
+}
+[@@deriving eq, ord]
+
+type pos = position * position [@@deriving eq, ord]
 (** The type pos is used to track the starting and ending position for the given
     location. *)
 
 type ('a, 'b) variable = { pos : 'a; name : string; index : 'b option }
+[@@deriving eq, ord]
 (** Describe a variable, using the name in capitalized text, and an optionnal
     index.
 
diff --git a/lib/syntax/catalog.ml b/lib/syntax/catalog.ml
index b516976..5ad0bbd 100644
--- a/lib/syntax/catalog.ml
+++ b/lib/syntax/catalog.ml
@@ -18,31 +18,31 @@ type ex =
       -> ex  (** Type of check to apply *)
 
 let build :
+    ?location_id:'a Type.Id.t ->
+    ?context_id:'b Type.Id.t ->
     (module S.Analyzer
        with type Expression.t = _
         and type Expression.t' = _
         and type Instruction.t = _
         and type Instruction.t' = _
         and type Location.t = 'a
-        and type context = _) ->
-    'a Type.Id.t * ex =
- fun module_ ->
+        and type context = 'b) ->
+    ex =
+ fun ?location_id ?context_id module_ ->
   let expr_witness = Type.Id.make ()
   and expr' = Type.Id.make ()
   and instr_witness = Type.Id.make ()
   and instr' = Type.Id.make ()
-  and location_witness = Type.Id.make ()
-  and context = Type.Id.make () in
-  let t =
-    E
-      {
-        module_;
-        expr_witness;
-        expr';
-        instr_witness;
-        instr';
-        location_witness;
-        context;
-      }
-  in
-  (location_witness, t)
+  and location_witness =
+    match location_id with Some v -> v | None -> Type.Id.make ()
+  and context = match context_id with Some v -> v | None -> Type.Id.make () in
+  E
+    {
+      module_;
+      expr_witness;
+      expr';
+      instr_witness;
+      instr';
+      location_witness;
+      context;
+    }
diff --git a/lib/syntax/catalog.mli b/lib/syntax/catalog.mli
index a256c17..a386d4a 100644
--- a/lib/syntax/catalog.mli
+++ b/lib/syntax/catalog.mli
@@ -18,13 +18,15 @@ type ex =
       -> ex  (** Type of check to apply *)
 
 val build :
+  ?location_id:'a Type.Id.t ->
+  ?context_id:'b Type.Id.t ->
   (module S.Analyzer
      with type Expression.t = _
       and type Expression.t' = _
       and type Instruction.t = _
       and type Instruction.t' = _
       and type Location.t = 'a
-      and type context = _) ->
-  'a Type.Id.t * ex
+      and type context = 'b) ->
+  ex
 (** Build a new check from a module following S.Analyzer signature. ypeid Return
     the result type which hold the final result value, and checker itself. *)
diff --git a/lib/syntax/dune b/lib/syntax/dune
index 666273f..9832809 100644
--- a/lib/syntax/dune
+++ b/lib/syntax/dune
@@ -2,5 +2,7 @@
  (name qsp_syntax)
  
  (preprocess (pps 
-   ppx_deriving.show ppx_deriving.enum
+   ppx_deriving.show 
+   ppx_deriving.enum
+   ppx_deriving.ord
    ppx_deriving.eq )))