OA26-022 move string utility function to string utility module

src/transform/intro_vc_vars_counterexmp.ml

@@ -194,12 +194,6 @@ let () = Trans.register_transform "intro_vc_vars_counterexmp"
   intro_vc_vars_counterexmp
   ~desc:"Introduce."
 
-let rec string_join sep l =
-  match l with
-  | [] -> ""
-  | [x] -> x
-  | x :: rest -> x ^ sep ^ string_join sep rest
-
 let get_location_of_vc task =
   let meta_args = Task.on_meta_excl meta_vc_location task in
   match meta_args with
@@ -214,7 +208,7 @@ let get_location_of_vc task =
 	let line = int_of_string line in
 	let col1 = int_of_string col1 in
 	let col2 = int_of_string col2 in
-	let filename = string_join ":" (List.rev rest) in
+	let filename = Strings.join ":" (List.rev rest) in
         Some (Loc.user_position filename line col1 col2)
       | _ -> None in
     loc

src/util/strings.ml

@@ -39,6 +39,12 @@ let rev_bounded_split c s n =
 
 let bounded_split c s n = List.rev (rev_bounded_split c s n)
 
+let rec join sep l =
+  match l with
+  | [] -> ""
+  | [x] -> x
+  | x :: rest -> x ^ sep ^ join sep rest
+
 let ends_with s suf =
   let rec aux s suf suflen offset i =
     i >= suflen || (s.[i + offset] = suf.[i]

src/util/strings.mli

@@ -32,6 +32,10 @@ val bounded_split : char -> string -> int -> string list
     [n] substring at most.
     The concatenation of returned substrings is equal to the string s.*)
 
+val join : string -> string list -> string
+(** [join sep l] joins all the strings in [l] together, in the same
+    order, separating them by [sep] *)
+
 val ends_with : string -> string -> bool
 (** test if a string ends with another *)