yesod-form-1.3.0: Form handling support for Yesod Web Framework

Safe HaskellNone




Running in MForm monad

newFormIdent :: Monad m => MForm m TextSource

Get a unique identifier.

Applicative/Monadic conversion

formToAForm :: (HandlerSite m ~ site, Monad m) => MForm m (FormResult a, [FieldView site]) -> AForm m aSource

aFormToForm :: (Monad m, HandlerSite m ~ site) => AForm m a -> MForm m (FormResult a, [FieldView site] -> [FieldView site])Source

Fields to Forms

mopt :: (site ~ HandlerSite m, MonadHandler m) => Field m a -> FieldSettings site -> Maybe (Maybe a) -> MForm m (FormResult (Maybe a), FieldView site)Source

areq :: (RenderMessage site FormMessage, HandlerSite m ~ site, MonadHandler m) => Field m a -> FieldSettings site -> Maybe a -> AForm m aSource

Run a form

runFormPost :: (RenderMessage (HandlerSite m) FormMessage, MonadResource m, MonadHandler m) => (Markup -> MForm m (FormResult a, xml)) -> m ((FormResult a, xml), Enctype)Source

This function is used to both initially render a form and to later extract results from it. Note that, due to CSRF protection and a few other issues, forms submitted via GET and POST are slightly different. As such, be sure to call the relevant function based on how the form will be submitted, not the current request method.

For example, a common case is displaying a form on a GET request and having the form submit to a POST page. In such a case, both the GET and POST handlers should use runFormPost.

runFormGet :: MonadHandler m => (Markup -> MForm m a) -> m (a, Enctype)Source

Generate a blank form

generateFormPost :: (RenderMessage (HandlerSite m) FormMessage, MonadHandler m) => (Markup -> MForm m (FormResult a, xml)) -> m (xml, Enctype)Source

Similar to runFormPost, except it always ignore the currently available environment. This is necessary in cases like a wizard UI, where a single page will both receive and incoming form and produce a new, blank form. For general usage, you can stick with runFormPost.


type FormRender m a = AForm m a -> Markup -> MForm m (FormResult a, WidgetT (HandlerSite m) IO ())Source

renderDivs :: Monad m => FormRender m aSource

render a field inside a div

renderDivsNoLabels :: Monad m => FormRender m aSource

render a field inside a div, not displaying any label

renderBootstrap :: Monad m => FormRender m aSource

Render a form using Bootstrap-friendly shamlet syntax.

Sample Hamlet:

  <form .form-horizontal method=post action=@{ActionR} enctype=#{formEnctype}>
      $case result
        $of FormFailure reasons
          $forall reason <- reasons
            <div .alert .alert-error>#{reason}
        $of _
      <div .form-actions>
        <input .btn .primary type=submit value=_{MsgSubmit}>


check :: (Monad m, RenderMessage (HandlerSite m) msg) => (a -> Either msg a) -> Field m a -> Field m aSource

checkBool :: (Monad m, RenderMessage (HandlerSite m) msg) => (a -> Bool) -> msg -> Field m a -> Field m aSource

Return the given error message if the predicate is false.

checkM :: (Monad m, RenderMessage (HandlerSite m) msg) => (a -> m (Either msg a)) -> Field m a -> Field m aSource

checkMMap :: (Monad m, RenderMessage (HandlerSite m) msg) => (a -> m (Either msg b)) -> (b -> a) -> Field m a -> Field m bSource

Same as checkM, but modifies the datatype.

In order to make this work, you must provide a function to convert back from the new datatype to the old one (the second argument to this function).

Since 1.1.2

customErrorMessage :: Monad m => SomeMessage (HandlerSite m) -> Field m a -> Field m aSource

Allows you to overwrite the error message on parse error.


fieldSettingsLabel :: RenderMessage site msg => msg -> FieldSettings siteSource

Generate a FieldSettings from the given label.

parseHelper :: (Monad m, RenderMessage site FormMessage) => (Text -> Either FormMessage a) -> [Text] -> [FileInfo] -> m (Either (SomeMessage site) (Maybe a))Source

A helper function for creating custom fields.

This is intended to help with the common case where a single input value is required, such as when parsing a text field.

Since 1.1