clean up and 0 length fix

Author: Hongbo Zhang

jscomp/lam_compile_external_call.ml

@@ -251,7 +251,7 @@ let translate_ffi (ffi : Ast_external_attributes.ffi ) prim_name
 
 let translate cxt 
     ({prim_name ;  prim_native_name} 
-     : Ast_external_attributes.prim) args  = 
+     : Primitive.description) args  = 
   if Ast_external_attributes.is_bs_external_prefix prim_native_name then 
     begin 
       match Ast_external_attributes.unsafe_from_string prim_native_name with 

jscomp/syntax/ast_external_attributes.ml

@@ -70,7 +70,7 @@ type ffi =
   | Js_get_index
   | Js_set_index
 
-type prim =  Primitive.description
+
 
 let valid_js_char =
   let a = Array.init 256 (fun i ->
@@ -89,7 +89,7 @@ let valid_first_js_char =
 (** Approximation could be improved *)
 let valid_ident (s : string) =
   let len = String.length s in
-  valid_js_char s.[0] && valid_first_js_char s.[0] &&
+  len > 0 && valid_js_char s.[0] && valid_first_js_char s.[0] &&
   (let module E = struct exception E end in
    try
      for i = 1 to len - 1 do
@@ -100,21 +100,18 @@ let valid_ident (s : string) =
    with E.E -> false )  
 
 let valid_global_name ?loc txt =
-  let error () =
-    Location.raise_errorf ?loc "Not a valid  name %s"  txt  in
-  if txt = "" then
-    error ()
-  else
+  if not (valid_ident txt) then
     let v = Ext_string.split_by ~keep_empty:true (fun x -> x = '.') txt in
     List.iter
       (fun s ->
-         if not (valid_ident s) then error ()
+         if not (valid_ident s) then
+           Location.raise_errorf ?loc "Not a valid  name %s"  txt
       ) v      
 
 let valid_method_name ?loc txt =         
-  let error () =
-    Location.raise_errorf ?loc "Not a valid  name %s"  txt  in
-  if not (valid_ident txt) then error ()
+  if not (valid_ident txt) then
+    Location.raise_errorf ?loc "Not a valid  name %s"  txt
+
 
 
 let check_external_module_name ?loc x = 

jscomp/syntax/ast_external_attributes.mli

@@ -74,7 +74,7 @@ type t  =
   | Bs of arg_kind list  * arg_type *   ffi
   | Normal 
 
-type prim =  Primitive.description
+