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1. maybeWarningLeaf :: Leaf name str -> Maybe String

   wraxml	Text.XML.WraXML.Tree

   No documentation available.

2. maybeAuthId :: (YesodAuth master, MonadHandler m, master ~ HandlerSite m) => m (Maybe (AuthId master))

   yesod-auth-oauth2	Yesod.Auth.OAuth2.Prelude

   Retrieves user credentials, if user is authenticated. By default, this calls defaultMaybeAuthId to get the user ID from the session. This can be overridden to allow authentication via other means, such as checking for a special token in a request header. This is especially useful for creating an API to be accessed via some means other than a browser.

3. maybeMult :: Num a => Maybe a -> Maybe a -> Maybe a

   yi-keymap-vim	Yi.Keymap.Vim.StateUtils

   No documentation available.

4. maybeMP :: MonadPlus m => Maybe a -> m a

   IfElse	Control.Monad.IfElse

   This conversion is common enough to make a name for.

5. maybeAtom :: Alternative p => p a -> Perms p (Maybe a)

   action-permutations	Control.Applicative.Permutation

   Like atom, but the action may be omitted from the permutation.

   • runPerms (maybeAtom p) = Just
     <$> p <|> pure
     Nothing

   When building permutation parsers, the argument parser should not match the empty string.

6. maybeQuot :: IntegralDomain d => d -> d -> Maybe d

   algebra	Numeric.Domain.Integral

   No documentation available.

7. maybeDelegate :: MonadDelegate r m => r -> m (Maybe a) -> m a

   alternators	Control.Monad.Delegate

   maybe delegate the Just value, or just use the r.

8. maybeAuthorized :: Yesod site => Route site -> Bool -> HandlerT site IO (Maybe (Route site))

   classy-prelude-yesod	ClassyPrelude.Yesod

   Return the same URL if the user is authorized to see it. Built on top of isAuthorized. This is useful for building page that only contain links to pages the user is allowed to see.

9. maybeC :: forall (m :: Type -> Type) i o a . Monad m => ConduitT i o m (Maybe a) -> ConduitT i o (MaybeT m) a

   classy-prelude-yesod	ClassyPrelude.Yesod

   Wrap the base monad in MaybeT Since 1.0.11

10. maybeToList :: Maybe a -> [a]

    classy-prelude-yesod	ClassyPrelude.Yesod

    The maybeToList function returns an empty list when given Nothing or a singleton list when given Just.

    Examples

    Basic usage:

    >>> maybeToList (Just 7)
    [7]
    

    >>> maybeToList Nothing
    []
    

    One can use maybeToList to avoid pattern matching when combined with a function that (safely) works on lists:

    >>> import GHC.Internal.Text.Read ( readMaybe )
    
    >>> sum $ maybeToList (readMaybe "3")
    3
    
    >>> sum $ maybeToList (readMaybe "")
    0
    

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