Language.KURE.Combinators.Monad

This module provides conditional monadic combinators.

Monadic Conditionals

guardMsg :: MonadFail m => Bool -> String -> m ()

Similar to guard, but invokes fail rather than mzero.

guardM :: MonadFail m => Bool -> m ()

As guardMsg, but with a default error message.

guardMsgM :: MonadFail m => m Bool -> String -> m ()

As guardMsg, but with an m Bool as argument.

ifM :: Monad m => m Bool -> m a -> m a -> m a

if-then-else lifted over a monadic predicate.

whenM :: MonadFail m => m Bool -> m a -> m a

If the monadic predicate holds then perform the monadic action, else fail.

unlessM :: MonadFail m => m Bool -> m a -> m a

If the monadic predicate holds then fail, else perform the monadic action.