Add an example for LTerm_read_line.read_keyword.

examples/dune

@@ -16,6 +16,7 @@
         shell
         repl
         modal
+        read_keyword
         read_password
         read_yes_no
         editor)

examples/read_keyword.ml

@@ -0,0 +1,48 @@
+(*
+ * read_keyword.ml
+ * ----------------
+ * Copyright : (c) 2022, Shiwei Weng <[email protected]>
+ * Licence   : BSD3
+ *
+ * This file is a part of Lambda-Term.
+ *)
+
+(* Read a keyword and display it. *)
+
+open Lwt_react
+let ( >>= ) = Lwt.( >>= )
+
+type move = Play | Pause
+
+class read_keyword term = object(self)
+  inherit [move] LTerm_read_line.read_keyword () as super
+  inherit [move LTerm_read_line.read_keyword_result] LTerm_read_line.term term
+
+  method! send_action = function
+    | LTerm_read_line.Break ->
+        (* Ignore Ctrl+C *)
+        ()
+    | action ->
+        super#send_action action
+
+  method! keywords = [
+    Zed_string.of_utf8 "play", Play;
+    Zed_string.of_utf8 "pause", Pause
+  ]
+
+  initializer
+    self#set_prompt (S.const (LTerm_text.of_utf8 "Type a read_keyword: "))
+end
+
+let main () =
+  LTerm_inputrc.load ()
+  >>= fun () ->
+  Lazy.force LTerm.stdout
+  >>= fun term ->
+  (new read_keyword term)#run
+  >>= function
+    | Rk_value Play -> Lwt_io.printlf "You played it"
+    | Rk_value Pause -> Lwt_io.printlf "You paused it"
+    | Rk_error _ -> Lwt_io.printlf "You didn't type a keyword"
+
+let () = Lwt_main.run (main ())