Documentation

Collects all thrown warnings in StateT and errors in ExceptT into a single value using Monoid.

Returns mempty instead of error if no warnings have occurred. Returns Nothing as the second element of tuple if computation was interrupted by vError.

Returns all concatenated errors and warnings and the result if no errors have occurred (warnings could have occurred).

>>> :{
 runValidationT $ do
   vWarning ["warning1"]
   vError ["error"]
   vWarning ["warning2"]
   return 8
:}
(["error","warning1"],Nothing)

>>> :{
 runValidationT $ do
   vWarning ["warning1"]
   vWarning ["warning2"]
   return 8
:}
(["warning1","warning2"],Just 8)

Like runValidationT but doesn't return the result if any warning has occurred.

>>> :{
 runValidationTEither $ do
   vWarning ["warning1"]
   vError ["error"]
   vWarning ["warning2"]
   return 8
:}
Left ["error","warning1"]

>>> :{
 runValidationTEither $ do
   vWarning ["warning1"]
   vWarning ["warning2"]
   return 8
:}
Left ["warning1","warning2"]

Like runValidationTEither, but takes an error handler instead of returning errors and warnings.

>>> :{
 handleValidationT (\_ -> return 11) $ do
   vWarning ["warning1"]
   vError ["error"]
   vWarning ["warning2"]
   return 8
:}
11

>>> :{
 handleValidationT (\_ -> return 11) $ do
   vWarning ["warning1"]
   vWarning ["warning2"]
   return 8
:}
11

Stops further execution and appends the given error.

Does not stop further execution and appends the given warning.

Like vError but allows you to use a setter to insert an error somewhere deeper into an empty (mempty) "e" from "ValidationT e m x", which is then combined with all gathered warnings.

Like vWarning but allows you to use a setter to insert an error somewhere deeper into an empty (mempty) "e" from "ValidationT e m x", which is then combined with all gathered warnings.

Allows you apply a transformation to the "e" in "ValidationT e m x".

>>> :{
runValidationT . vZoom (Data.Map.singleton "password errors") $ do
 vWarning ["warning1"]
 vError ["error"]
 vWarning ["warning2"]
 return 8
:}
(fromList [("password errors",["error","warning1"])],Nothing)

>>> :{
 runValidationT . vZoom (Data.Map.singleton "password errors") $ do
   vWarning ["warning1"]
   vWarning ["warning2"]
   return 8
:}
(fromList [("password errors",["warning1","warning2"])],Just 8)

Like vZoom but takes a setter instead of a function.

Turn any warnings the have occurred into errors.

Convenient for vZoom as first argument. Will prevent generation of map with mempty values.

Sets given value to mempty.

Returns the strings, concatanated with ", " if the list is not empty.

Returns Nothing if the list is empty

>>> textErrors ["foo", "bar"]
Just "foo, bar"

>>> textErrors ["foo"]
Just "foo"

>>> textErrors []
Nothing

Map with Monoid instance which mappend its values

This can be used as the e in `ValidationT e m a` to provide different sets of errors and warnings for different keys.

>>> :{
  mconcat
  [ MonoidMap $ M.fromList [(1, "foo"), (2, "hello, "), (3, "oh no")]
  , MonoidMap $ M.fromList [(1, "bar"), (2, "world")]
  ]
:}
MonoidMap (fromList [(1,"foobar"),(2,"hello, world"),(3,"oh no")])