[refactoring] clean up

Author: Hongbo Zhang

jscomp/syntax/ast_comb.ml

@@ -56,3 +56,20 @@ let create_local_external loc
        pexp_attributes = [];
        pexp_loc = loc
      })
+
+open Ast_helper 
+
+let exp_apply_no_label ?loc ?attrs a b = 
+  Exp.apply ?loc ?attrs a (List.map (fun x -> "", x) b)
+
+let fun_no_label ?loc ?attrs  pat body = 
+  Exp.fun_ ?loc ?attrs "" None pat body
+
+let arrow_no_label ?loc ?attrs b c = 
+  Typ.arrow ?loc ?attrs "" b c 
+
+let discard_exp_as_unit loc e = 
+  exp_apply_no_label ~loc     
+    (Exp.ident ~loc {txt = Ast_literal.Lid.ignore_id; loc})
+    [Exp.constraint_ ~loc e 
+       (Ast_literal.type_unit ~loc ())]

jscomp/syntax/ast_comb.mli

@@ -29,3 +29,27 @@ val create_local_external : Location.t ->
   ?local_module_name:string ->
   ?local_fun_name:string ->
   (Asttypes.label * Parsetree.expression) list -> Parsetree.expression_desc
+
+val exp_apply_no_label : 
+  ?loc:Location.t ->
+  ?attrs:Parsetree.attributes ->
+  Parsetree.expression -> Parsetree.expression list -> Parsetree.expression
+
+val fun_no_label : 
+  ?loc:Location.t ->
+  ?attrs:Parsetree.attributes ->
+  Parsetree.pattern -> Parsetree.expression -> Parsetree.expression
+
+val arrow_no_label : 
+  ?loc:Location.t ->
+  ?attrs:Parsetree.attributes ->
+  Parsetree.core_type -> Parsetree.core_type -> Parsetree.core_type
+
+(* note we first declare its type is [unit], 
+   then [ignore] it, [ignore] is necessary since 
+   the js value  maybe not be of type [unit] and 
+   we can use [unit] value (though very little chance) 
+   sometimes
+*)
+val discard_exp_as_unit : 
+  Location.t -> Parsetree.expression -> Parsetree.expression

jscomp/syntax/ast_literal.ml

@@ -22,6 +22,8 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)
 
+open Ast_helper
+
 module Lid = struct 
   type t = Longident.t 
   let val_unit : t = Lident "()"
@@ -47,11 +49,14 @@ module No_loc = struct
     Ast_helper.Typ.mk  (Ptyp_constr ({ txt = Lid.type_string; loc}, []))
 
   let type_any = Ast_helper.Typ.any ()
+  let pat_unit = Pat.construct {txt = Lid.val_unit; loc} None
 end 
 
 type 'a  lit = ?loc: Location.t -> unit -> 'a
 type expression_lit = Parsetree.expression lit 
 type core_type_lit = Parsetree.core_type lit 
+type pattern_lit = Parsetree.pattern lit 
+
 let val_unit ?loc () = 
   match loc with 
   | None -> No_loc.val_unit
@@ -76,3 +81,9 @@ let type_any ?loc () =
   match loc with 
   | None -> No_loc.type_any
   | Some loc -> Ast_helper.Typ.any ~loc ()
+
+let pat_unit ?loc () = 
+  match loc with 
+  | None -> No_loc.pat_unit
+  | Some loc -> 
+    Pat.construct ~loc {txt = Lid.val_unit; loc} None

jscomp/syntax/ast_literal.mli

@@ -37,6 +37,7 @@ end
 
 type expression_lit = Parsetree.expression lit 
 type core_type_lit = Parsetree.core_type lit 
+type pattern_lit = Parsetree.pattern lit 
 
 val val_unit : expression_lit
 
@@ -46,4 +47,4 @@ val type_string : core_type_lit
 
 val type_any : core_type_lit
 
-
+val pat_unit : pattern_lit

jscomp/syntax/ast_payload.ml

@@ -48,6 +48,11 @@ let as_string_exp (x : t ) =
       _}] -> Some e
   | _  -> None
 
+let as_empty_structure (x : t ) = 
+  match x with 
+  | PStr ([]) -> true
+  | PTyp _ | PPat _ | PStr (_ :: _ ) -> false 
+
 let is_string_or_strings (x : t) : 
   [ `None | `Single of string | `Some of string list ] = 
   let module M = struct exception Not_str end  in 

jscomp/syntax/ast_payload.mli

@@ -31,6 +31,6 @@ type t = Parsetree.payload
 
 val is_single_string : t -> string option
 val as_string_exp : t -> Parsetree.expression option 
-
+val as_empty_structure :  t -> bool 
 val is_string_or_strings : 
   t -> [ `None | `Single of string | `Some of string list ]