Checkboxes communicate "no selection" properly

flex-tasks/src/FlexTask/FormUtil.hs

@@ -199,7 +199,7 @@ function setDefaults(values){
       else if(fieldType != null && fieldType.toLowerCase() === "checkbox"){
         field.checked = input.includes(field.getAttribute("value"));
       }
-      else{
+      else if(fieldType != null && fieldType.toLowerCase() !== "hidden"){
         var inputElem = fields.length > 1 ? JSON.parse(input)[j] : input;
         if(inputElem != "Missing" && inputElem != "None"){
           field.value = inputElem;

flex-tasks/src/FlexTask/Generic/Form.hs

@@ -56,10 +56,10 @@ import Data.Text            (Text, pack, unpack)
 import Yesod
 
 import FlexTask.Widgets
-  ( horizontalRadioField
+  ( checkboxField
+  , horizontalRadioField
   , joinRenders
   , renderForm
-  , verticalCheckboxesField
   )
 import FlexTask.YesodConfig (FlexForm, Handler, Rendered)
 
@@ -566,8 +566,8 @@ renderNextMultipleChoiceField pairsWith =
                                       , True
                                       , areq $
                                           case align of
-                                            Vertical -> verticalCheckboxesField
-                                            Horizontal -> checkboxesField
+                                            Vertical   -> checkboxField True
+                                            Horizontal -> checkboxField False
                                           $ withOptions opts
                                       )
       _ -> error "Incorrect naming scheme for a multi choice!"

flex-tasks/src/FlexTask/Generic/ParseInternal.hs

@@ -179,7 +179,7 @@ instance Parse SingleChoiceSelection where
 
 
 instance Parse MultipleChoiceSelection where
-  parseInput = multipleChoiceAnswer <$> parseInput
+  parseInput = multipleChoiceAnswer <$> parseWithEmptyMarker
 
 
 
@@ -200,7 +200,12 @@ parseInstanceSingleChoice = toEnum . subtract 1 <$> parseInput
 
 -- | Same as `parseInstanceSingleChoice`, but for parsing a List of the given type, i.e. a multiple choice version.
 parseInstanceMultiChoice :: (Bounded a, Enum a, Eq a) => Parser [a]
-parseInstanceMultiChoice = map (toEnum . subtract 1) <$> parseInput
+parseInstanceMultiChoice = map (toEnum . subtract 1) <$> parseWithEmptyMarker
+
+
+
+parseWithEmptyMarker :: Parser [Int]
+parseWithEmptyMarker = filter (<0) <$> parseInput
 
 
 

flex-tasks/src/FlexTask/Widgets.hs

@@ -97,19 +97,27 @@ $newline never
 
 
 
-verticalCheckboxesField :: Eq a => Handler (OptionList a) -> Field Handler [a]
-verticalCheckboxesField optList = (multiSelectField optList)
+checkboxField :: Eq a => Bool -> Handler (OptionList a) -> Field Handler [a]
+checkboxField isVertical optList = (multiSelectField optList)
       { fieldView =
           \theId title attrs val _isReq -> do
               os <- olOptions <$> handlerToWidget optList
-              let optSelected (Left _) _ = False
-                  optSelected (Right values) opt = optionInternalValue opt `elem` values
+              let selected (Left _) _ = False
+                  selected (Right values) opt = optionInternalValue opt `elem` values
+                  checkboxWidget opt = [whamlet|
+<label>
+  <input type=checkbox name=#{title} value=#{optionExternalValue opt} *{attrs} :selected val opt:checked>
+  #{optionDisplay opt}
+|]
               [whamlet|
 <span ##{theId}>
+  <input type=hidden name=#{title} value=-1>
   $forall opt <- os
-    <div>
-      <label>
-        <input type=checkbox name=#{title} value=#{optionExternalValue opt} *{attrs} :optSelected val opt:checked>
-        #{optionDisplay opt}
+    $with box <- checkboxWidget opt
+      $if isVertical
+        <div>
+          ^{box}
+      $else
+        ^{box}
 |]
       }

flex-tasks/test/FlexTask/Generic/ParseSpec.hs

@@ -82,19 +82,20 @@ spec = do
     prop "single choice works" $ \i ->
       useParser parseInput (escapedSingle $ show i) `shouldParse` singleChoiceAnswer i
     prop "multiple choice works" $ \is ->
-      useParser parseInput (escapedList $ map show is) `shouldParse` multipleChoiceAnswer is
+      useParser parseInput (escapedList $ map show is) `shouldParse` multipleChoiceAnswer (removeEmpty is)
 
   describe "choice selection parsers (for a test enum)" $ do
     specify "single choice works" $
       forAll (chooseInt (0,2)) $ \i ->
         useParser parseInput (escapedSingle $ show $ i+1) `shouldParse` toEnum @TestEnum i
     specify "multiple choice works" $
       forAll (sublistOf [0..2]) $ \is ->
-        useParser parseInput (escapedList $ map (show . (+1)) is) `shouldParse` map (toEnum @TestEnum) is
+        useParser parseInput (escapedList $ map (show . (+1)) is) `shouldParse` map (toEnum @TestEnum) (removeEmpty is)
   where
     testParse = many1 digit
     boolShow b = if b then "yes" else "no"
     maybeShow = maybe "None"
+    removeEmpty = filter (<0)
 
     testParsingMaybeStringList fromString = testParsingStringList (with fromString)
     testParsingMaybe from = testParsingString (with from)