constructor: add a create function

The previous interface wasn't great in that required users to know that
they should partially apply the dispatch function. Now, for both regular
route description and the DSL route description, there's constructor to
the same shared type t. With values of this type, users can now call a
single dispatch function to get a handler for a path.

js/dispatch_js.ml

@@ -32,14 +32,3 @@ let dispatch_on_fragment ?(on_failure=default_on_failure) ?(default="/") routes
     frag_loop
   | current ->
     go current >>= fun _ -> frag_loop
-
-module DSL = struct
-  let convert routes =
-    List.map (fun (m, x) ->
-      let ts, t = Dispatch.of_dsl m in
-      ts, t, x)
-    routes
-
-  let dispatch_on_fragment ?on_failure ?default routes =
-    dispatch_on_fragment ?on_failure ?default (convert routes)
-end

js/dispatch_js.mli

@@ -36,22 +36,13 @@
     Dispatch_js makes it easy for js_of_ocaml applications to monitor and react
     to changes in URI fragments. *)
 
-open Dispatch
-
-val dispatch_on_fragment :
-  ?on_failure:(string -> unit Lwt.t) -> ?default:string ->
-  unit Lwt.t route list -> unit Lwt.t
+val dispatch_on_fragment
+  :  ?on_failure:(string -> unit Lwt.t)
+  -> ?default:string
+  -> unit Lwt.t Dispatch.t
+  -> unit Lwt.t
 (** [dispatch_on_fragment ?on_failure ?default routes] will monitor the URL
     fragment and dispatch to the appropriate hander in [routes]. In the event
     that the fragment does not match any routes, [on_failure] will be called,
     if provided, with the fragment. On setup the fragment will be set to
     [default], or ["/"] if no default is provided. *)
-
-module DSL : sig
-
-  val dispatch_on_fragment : 
-    ?on_failure:(string -> unit Lwt.t) -> ?default:string ->
-    unit Lwt.t DSL.route list -> unit Lwt.t
-  (** [dispatch_on_fragment ?on_failure ?default routes] is the same as the
-      non-DSL version with the exception of the route type. *)
-end

lib/dispatch.ml

@@ -40,6 +40,10 @@ type typ =
 type assoc = (string * string) list
 type 'a route = (tag * string) list * typ * (assoc -> string option -> 'a)
 
+type 'a t = 'a route list
+
+let create t = t
+
 let path_split path =
   (* NOTE(seliopou): This was implemented manually to minimize dependencies for
    * js_of_ocaml. Ain't nobody got time for another regular expression library
@@ -129,15 +133,9 @@ let dispatch_exn routes path =
 module DSL = struct
   type 'a route = string * (assoc -> string option -> 'a)
 
-  let convert routes =
+  let create routes =
     List.map (fun (m, x) ->
       let ts, t = of_dsl m in
       ts, t, x)
     routes
-
-  let dispatch routes =
-    dispatch (convert routes)
-
-  let dispatch_exn routes =
-    dispatch_exn (convert routes)
 end

lib/dispatch.mli

@@ -68,8 +68,12 @@ type 'a route = (tag * string) list * typ * (assoc -> string option -> 'a)
     route match, the matching information will be passed to the handler to
     produce a value of tyoe ['a] that will be returned. *)
 
-val dispatch     : 'a route list -> string -> 'a option
-val dispatch_exn : 'a route list -> string -> 'a
+type 'a t
+
+val create : 'a route list -> 'a t
+
+val dispatch     : 'a t -> string -> 'a option
+val dispatch_exn : 'a t -> string -> 'a
 (** [dispatch routes path] iterates through [routes] and selects the first one
     that matches [path]. It then applies the route handler to any component
     mappings and trailing path components (in the case of a prefix match) and
@@ -104,6 +108,5 @@ module DSL : sig
   # of_dsk "/user/:id/settings";;
     = ([`Lit, "user"; `Var, "id"; `Lit, "settings"], `Exact) v} *)
 
-  val dispatch     : 'a route list -> string -> 'a option
-  val dispatch_exn : 'a route list -> string -> 'a
+  val create : 'a route list -> 'a t
 end

test/test_dispatch.ml

@@ -44,29 +44,31 @@ open Alcotest
 
 let assoc = list (pair string string)
 
-open Dispatch.DSL
+open Dispatch
 
 let literals = 
   "literals", [
     "base cases", `Quick, begin fun () ->
-      let t0, t1 = ["/", fun _ _ -> ()], ["", fun _ _ -> ()] in
+      let t0, t1 = DSL.create ["/", fun _ _ -> ()], DSL.create ["", fun _ _ -> ()] in
+      let empty = DSL.create [] in
       let check = Alcotest.check (option unit) in
       let test_ok  ~msg tbl p = check msg (dispatch tbl p) (Some ()) in
       let test_err ~msg tbl p = check msg (dispatch tbl p) None in
-      test_err [] "/"     ~msg:"empty table produces errors";
-      test_ok  t0 "/"     ~msg:"empty path string maps to root";
-      test_ok  t1 ""      ~msg:"empty route path matches root";
-      test_err t0 "/foo"  ~msg:"root entry won't dispatch others";
+      test_err empty "/"     ~msg:"empty table produces errors";
+      test_ok  t0    "/"     ~msg:"empty path string maps to root";
+      test_ok  t1    ""      ~msg:"empty route path matches root";
+      test_err t0    "/foo"  ~msg:"root entry won't dispatch others";
     end;
     "overlaping paths", `Quick, begin fun () ->
       let t0 =
-        [ ("/foo"    , base_path "/foo")
-        ; ("/foo/bar", base_path "/foo/bar")
-        ; ("/foo/baz", base_path "/foo/baz")
-        ; ("/bar/baz", base_path "/bar/baz")
-        ; ("/bar/foo", base_path "/bar/foo")
-        ; ("/bar"    , base_path "/bar")
-        ]
+        DSL.create
+          [ ("/foo"    , base_path "/foo")
+          ; ("/foo/bar", base_path "/foo/bar")
+          ; ("/foo/baz", base_path "/foo/baz")
+          ; ("/bar/baz", base_path "/bar/baz")
+          ; ("/bar/foo", base_path "/bar/foo")
+          ; ("/bar"    , base_path "/bar")
+          ]
       in
       let check = Alcotest.check (option string) in
       let test_ok ~msg p = check msg (dispatch t0 p) (Some p) in
@@ -80,10 +82,11 @@ let params =
   "params", [
     "base cases", `Quick, begin fun () ->
       let t0 =
-        [ ("/foo/:id"         , param_path "id")
-        ; ("/foo/:id/:bar"    , param_path "bar")
-        ; ("/foo/:id/bar/:baz", param_path "baz")
-        ]
+        DSL.create
+          [ ("/foo/:id"         , param_path "id")
+          ; ("/foo/:id/:bar"    , param_path "bar")
+          ; ("/foo/:id/bar/:baz", param_path "baz")
+          ]
       in
       let check = Alcotest.check (option string) in
       let test_ok ~msg p v = check msg (dispatch t0 p) (Some v) in
@@ -93,9 +96,10 @@ let params =
     end;
     "variable ordering", `Quick, begin fun () ->
       let t0 =
-        [ ("/test/:z/:x/:y/"      , params)
-        ; ("/test/:x/:y/order/:z/", params)
-        ]
+        DSL.create
+          [ ("/test/:z/:x/:y/"      , params)
+          ; ("/test/:x/:y/order/:z/", params)
+          ]
       in
       let check = Alcotest.check (option assoc) in
       let test_ok ~msg p v = check msg (dispatch t0 p) (Some v) in
@@ -109,7 +113,7 @@ let params =
 
 let wildcards =
   "wildcard", [
-    let t0 = ["/foo/*", disp_path] in
+    let t0 = DSL.create ["/foo/*", disp_path] in
     let check = Alcotest.check (option string) in
     let test_ok ~msg p v = check msg (dispatch t0 p) (Some v) in
     "base cases", `Quick, begin fun () ->