Enable re-editing of source code

src/webInterface/model.ml

@@ -32,6 +32,7 @@ type msg =
   | UseStdlib of bool
   | ChangeSource of string
   | LoadSource
+  | EditSource
   | SelectReduction of int option
   | Step of Interpreter.top_step
   | RandomStep
@@ -134,6 +135,7 @@ let update model = function
             ( (if model.use_stdlib then Loader.stdlib_source else "")
             ^ "\n\n\n" ^ model.unparsed_code );
       }
+  | EditSource -> { model with loaded_code = Error "" }
   | ChangeRandomStepSize random_step_size -> { model with random_step_size }
   | ChangeInterruptOperation operation ->
       { model with interrupt_operation = Some operation }

src/webInterface/view.ml

@@ -112,7 +112,20 @@ let step_action (red, step) =
     elt "ol" (back_action ::  :: step_actions @ [interrupt_action]) *)
 
 let view_steps (model : Model.model) (code : Model.loaded_code) steps =
-  let view_undo_last_step =
+  let view_edit_source =
+    panel_block
+      [
+        elt "button"
+          ~a:
+            [
+              class_ "button is-outlined is-fullwidth is-small is-danger";
+              onclick (fun _ -> Model.EditSource);
+              attr "title"
+                "Re-editing source code will abort current evaluation";
+            ]
+          [ text "Re-edit source code" ];
+      ]
+  and view_undo_last_step =
     panel_block
       [
         elt "button"
@@ -240,7 +253,7 @@ let view_steps (model : Model.model) (code : Model.loaded_code) steps =
   in
   panel "Interaction"
     ~a:[ onmousemove (fun _ -> Model.SelectReduction None) ]
-    ( view_undo_last_step :: view_random_steps steps
+    ( view_edit_source :: view_undo_last_step :: view_random_steps steps
       :: List.mapi view_step steps
     @ [ send_interrupt ] )