Use if_list

Signed-off-by: Etienne Millon <me@emillon.org>

src/action.ml

@@ -368,12 +368,13 @@ module Unexpanded = struct
   include Make_ast(String_with_vars)(String_with_vars)(String_with_vars)(Uast)
 
   let t =
-    let open Sexp.Of_sexp in
-    peek_exn >>= function
-    | Template _ | Atom _ | Quoted_string _ as sexp ->
-      of_sexp_errorf (Sexp.Ast.loc sexp)
-        "if you meant for this to be executed with bash, write (bash \"...\") instead"
-    | List _ -> t
+    if_list
+      ~then_:t
+      ~else_:
+        (loc >>| fun loc ->
+         of_sexp_errorf
+           loc
+           "if you meant for this to be executed with bash, write (bash \"...\") instead")
 
   let check_mkdir loc path =
     if not (Path.is_managed path) then

src/jbuild.ml

@@ -327,10 +327,9 @@ module Dep_conf = struct
            Source_tree x)
         ]
     in
-    peek_exn >>= function
-    | Template _ | Atom _ | Quoted_string _ ->
-      String_with_vars.t >>| fun x -> File x
-    | List _ -> t
+    if_list
+      ~then_:t
+      ~else_:(String_with_vars.t >>| fun x -> File x)
 
   open Sexp
   let sexp_of_t = function
@@ -1032,12 +1031,13 @@ module Executables = struct
       Sexp.Of_sexp.enum simple_representations
 
     let t =
-      peek_exn >>= function
-      | List _ ->
-        enter (let%map mode = Mode_conf.t
-               and kind = Binary_kind.t in
-               { mode; kind })
-      | _ -> simple
+      if_list
+        ~then_:
+          (enter
+             (let%map mode = Mode_conf.t
+              and kind = Binary_kind.t in
+              { mode; kind }))
+        ~else_:simple
 
     let simple_sexp_of_t link_mode =
       let is_ok (_, candidate) =

src/stdune/path.ml

@@ -602,17 +602,17 @@ let of_string ?error_loc s =
       make_local_path (Local.of_string s ?error_loc)
 
 let t =
-  Sexp.Of_sexp.(
-    peek_exn >>= function
-    | Template _ | Atom _ | Quoted_string _ ->
+  let open Sexp.Of_sexp in
+  if_list
+    ~then_:
+      (sum
+         [ "In_build_dir"  , Local.t    >>| in_build_dir
+         ; "In_source_tree", Local.t    >>| in_source_tree
+         ; "External"      , External.t >>| external_
+         ])
+    ~else_:
       (* necessary for old build dirs *)
-      plain_string (fun ~loc:_ s -> of_string s)
-    | List _ ->
-      sum
-        [ "In_build_dir"  , Local.t    >>| in_build_dir
-        ; "In_source_tree", Local.t    >>| in_source_tree
-        ; "External"      , External.t >>| external_
-        ])
+      (plain_string (fun ~loc:_ s -> of_string s))
 
 let sexp_of_t t =
   let constr f x y = Sexp.To_sexp.(pair string f) (x, y) in