Control.Monad.Trans.Except

DescriptionThis monad transformer extends a monad with the ability to throw and catch exceptions.A sequence of actions terminates normally, producing a value, only if none of the actions in the sequence throws an exception. If one throws an exception, the rest of the sequence is skipped and the composite action exits with that exception.If the value of the exception is not required, the variant in Control.Monad.Trans.Maybe may be used instead.

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