diff --git a/compiler/main/mls2obc.ml b/compiler/main/mls2obc.ml
index 631e31d..7874c04 100644
--- a/compiler/main/mls2obc.ml
+++ b/compiler/main/mls2obc.ml
@@ -327,7 +327,7 @@ and mk_node_call map call_context app loc name_list args =
           Env.add vd.Minils.v_ident a env in
         let subst_act_list env act_list =
           let exp funs env e = match e.e_desc with
-            | Elhs { l_desc = Lvar x } ->
+            | Elhs { pat_desc = Lvar x } ->
                 let e =
                   (try Env.find x env
                   with Not_found -> e) in
diff --git a/compiler/obc/c/cgen.ml b/compiler/obc/c/cgen.ml
index cf51ea1..8974644 100644
--- a/compiler/obc/c/cgen.ml
+++ b/compiler/obc/c/cgen.ml
@@ -303,7 +303,7 @@ and cop_of_op var_env op_name exps =
   let cexps = cexprs_of_exps var_env exps in
   cop_of_op_aux op_name cexps
 
-and clhs_of_lhs var_env l = match l.l_desc with
+and clhs_of_lhs var_env l = match l.pat_desc with
   (** Each Obc variable corresponds to a real local C variable. *)
   | Lvar v ->
       let n = name v in
@@ -339,7 +339,7 @@ let rec assoc_obj instance obj_env =
         else assoc_obj instance t
 
 let assoc_cn instance obj_env =
-  (assoc_obj (obj_call_name instance) obj_env).o_class
+  (assoc_obj (obj_ref_name instance) obj_env).o_class
 
 let is_op = function
   | { qual = "Pervasives"; name = _ } -> true
@@ -467,7 +467,7 @@ let rec cstm_of_act var_env obj_env act =
     | Acall (name_list, o, Mreset, args) ->
         assert_empty name_list;
         assert_empty args;
-        let on = obj_call_name o in
+        let on = obj_ref_name o in
         let obj = assoc_obj on obj_env in
         let classn = cname_of_qn obj.o_class in
         (match obj.o_size with
@@ -504,7 +504,7 @@ let rec cstm_of_act var_env obj_env act =
         generate_function_call var_env obj_env outvl objn args
 
     | Acall(_, o, Mmethod s, _) ->
-        let on = obj_call_name o in
+        let on = obj_ref_name o in
         let obj = assoc_obj on obj_env in
           Error.message obj.o_loc (Error.Eunknown_method s)
 
diff --git a/compiler/obc/obc.ml b/compiler/obc/obc.ml
index 1e663aa..e842dee 100644
--- a/compiler/obc/obc.ml
+++ b/compiler/obc/obc.ml
@@ -37,26 +37,26 @@ type const_dec = {
   c_type : ty;
   c_loc : location }
 
-type lhs = { l_desc : lhs_desc; l_ty : ty; l_loc : location }
+type pattern = { pat_desc : pat_desc; pat_ty : ty; pat_loc : location }
 
-and lhs_desc =
+and pat_desc =
   | Lvar of var_ident
   | Lmem of var_ident
-  | Lfield of lhs * field_name
-  | Larray of lhs * exp
+  | Lfield of pattern * field_name
+  | Larray of pattern * exp
 
 and exp = { e_desc : exp_desc; e_ty : ty; e_loc : location }
 
 and exp_desc =
-  | Elhs of lhs
+  | Elhs of pattern
   | Econst of static_exp
   | Eop of op_name * exp list
   | Estruct of type_name * (field_name * exp) list
   | Earray of exp list
 
-type obj_call =
+type obj_ref =
   | Oobj of obj_name
-  | Oarray of obj_name * lhs
+  | Oarray of obj_name * pattern
 
 type method_name =
   | Mreset
@@ -64,8 +64,8 @@ type method_name =
   | Mmethod of name
 
 type act =
-  | Aassgn of lhs * exp
-  | Acall of lhs list * obj_call * method_name * exp list
+  | Aassgn of pattern * exp
+  | Acall of pattern list * obj_ref * method_name * exp list
   | Acase of exp * (constructor_name * block) list
   | Afor of var_ident * static_exp * static_exp * block
 
@@ -113,7 +113,7 @@ let mk_exp ?(ty=invalid_type) ?(loc=no_location) desc =
   { e_desc = desc; e_ty = ty; e_loc = loc }
 
 let mk_lhs ?(ty=invalid_type) ?(loc=no_location) desc =
-  { l_desc = desc; l_ty = ty; l_loc = loc }
+  { pat_desc = desc; pat_ty = ty; pat_loc = loc }
 
 let mk_lhs_exp ?(ty=invalid_type) desc =
   let lhs = mk_lhs ~ty:ty desc in
@@ -127,7 +127,7 @@ let mk_block ?(locals=[]) eq_list =
     b_body = eq_list }
 
 let rec var_name x =
-  match x.l_desc with
+  match x.pat_desc with
     | Lvar x -> x
     | Lmem x -> x
     | Lfield(x,_) -> var_name x
@@ -155,7 +155,7 @@ let find_step_method cd =
 let find_reset_method cd =
   List.find (fun m -> m.m_name = Mreset) cd.cd_methods
 
-let obj_call_name o =
+let obj_ref_name o =
   match o with
     | Oobj obj
     | Oarray (obj, _) -> obj
diff --git a/compiler/obc/obc_mapfold.ml b/compiler/obc/obc_mapfold.ml
index 8100fa3..32cdde3 100644
--- a/compiler/obc/obc_mapfold.ml
+++ b/compiler/obc/obc_mapfold.ml
@@ -15,8 +15,8 @@ open Obc
 type 'a obc_it_funs = {
   exp:        'a obc_it_funs -> 'a -> Obc.exp -> Obc.exp * 'a;
   edesc:      'a obc_it_funs -> 'a -> Obc.exp_desc -> Obc.exp_desc * 'a;
-  lhs:        'a obc_it_funs -> 'a -> Obc.lhs -> Obc.lhs * 'a;
-  lhsdesc:    'a obc_it_funs -> 'a -> Obc.lhs_desc -> Obc.lhs_desc * 'a;
+  lhs:        'a obc_it_funs -> 'a -> Obc.pattern -> Obc.pattern * 'a;
+  lhsdesc:    'a obc_it_funs -> 'a -> Obc.pat_desc -> Obc.pat_desc * 'a;
   act:        'a obc_it_funs -> 'a -> Obc.act -> Obc.act * 'a;
   block:      'a obc_it_funs -> 'a -> Obc.block -> Obc.block * 'a;
   var_dec:    'a obc_it_funs -> 'a -> Obc.var_dec -> Obc.var_dec * 'a;
@@ -66,8 +66,8 @@ and edesc funs acc ed = match ed with
 
 and lhs_it funs acc l = funs.lhs funs acc l
 and lhs funs acc l =
-  let ld, acc = lhsdesc_it funs acc l.l_desc in
-  { l with l_desc = ld }, acc
+  let ld, acc = lhsdesc_it funs acc l.pat_desc in
+  { l with pat_desc = ld }, acc
 
 
 and lhsdesc_it funs acc ld =
diff --git a/compiler/obc/obc_printer.ml b/compiler/obc/obc_printer.ml
index 04d6bcc..18d4f4c 100644
--- a/compiler/obc/obc_printer.ml
+++ b/compiler/obc/obc_printer.ml
@@ -23,7 +23,7 @@ let print_obj ff o =
   fprintf ff "@]"
 
 let rec print_lhs ff e =
-  match e.l_desc with
+  match e.pat_desc with
     | Lvar x -> print_ident ff x
     | Lmem x -> fprintf ff "mem("; print_ident ff x; fprintf ff ")"
     | Lfield (l, f) -> print_lhs ff l; fprintf ff ".%s" (shortname f)