Disallow empty lists.

src/CacheSim/View.elm

@@ -96,13 +96,17 @@ viewRawCacheModelHierarchy rcmh =
             <| List.indexedMap viewRawCacheModel rcmh
         translationResult = Result.andThen validateCacheModelHierarchy
             <| translateRawCacheModelHierarchy rcmh
-        errorHtml =
+        checkedResult =
             case translationResult of
+                Ok h -> if h == [] then Err "Please specify at least one cache level." else Ok h
+                Err e -> Err e
+        errorHtml =
+            case checkedResult of
                 Ok _ -> viewError True ""
                 Err e -> viewError False e
         
         newButton = button "Add level" CreateRawModel
-        useButton = resultButton translationResult "Use hierarchy" (UseHierarchy << Just) 
+        useButton = resultButton checkedResult "Use hierarchy" (UseHierarchy << Just) 
     in
         div []
             [ h2 [] [ text "Cache hierarchy" ]
@@ -208,12 +212,17 @@ viewAccessInput m =
                 , item = Parser.int
                 , trailing = Parser.Optional
                 }
+        parseErrorToString _ = "Unable to parse input. Please enter a sequence of numbers separated by commas."
         parseResult = Parser.run (parser |. Parser.end) m.accessInput
-        accessButton = maybeButton (Result.toMaybe parseResult) "Access address" Access
-        errorHtml =
+        checkedResult =
             case parseResult of
+                Ok is -> if is == [] then Err "Please enter at least one number." else Ok is
+                Err e -> Err <| parseErrorToString e
+        accessButton = resultButton checkedResult "Access address" Access
+        errorHtml =
+            case checkedResult of
                 Ok _ -> viewError True ""
-                Err lde -> viewError False "Unable to parse input. Please enter a sequence of numbers separated by commas."
+                Err e -> viewError False e
         editHierarchyButton = button "Edit hierarchy" (UseHierarchy Nothing)
     in
         div []
@@ -258,6 +267,14 @@ viewBase m =
                         <| Maybe.map (List.singleton << viewCacheHierarchy) <| m.hierarchy
                 Just _ -> []
         accessView = Maybe.withDefault [] <| Maybe.map (List.singleton << viewAccessView m) <| Maybe.andThen (List.head) <| m.accessView
+        remainingAccessView =
+            case Maybe.map (\l -> List.length l - 1) m.accessView of
+                Just n -> if n <= 0 then [] else
+                    [ div [ class "alert", class "alert-info" ] [ text <|
+                        "Simulating more than one access. " ++ (String.fromInt n) ++
+                        " addresses in queue." ]
+                    ]
+                _ -> []
     in
         div [ class "container" ]
-            <| [ viewDescription] ++ rawView ++ accessInputView ++ accessView ++ cacheView
+            <| [ viewDescription] ++ rawView ++ accessInputView ++ remainingAccessView ++ accessView ++ cacheView