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Control.Monad.Trans.Maybe | Portability | portable | Stability | experimental | Maintainer | ross@soi.city.ac.uk |
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Description |
The MaybeT monad transformer adds the ability to fail to a monad.
A sequence of actions succeeds, producing a value, only if all the
actions in the sequence are successful. If one fails, the rest of
the sequence is skipped and the composite action fails.
For a variant allowing a range of error values, see
Control.Monad.Trans.Error.
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Synopsis |
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The MaybeT monad transformer
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The parameterizable maybe monad, obtained by composing an arbitrary
monad with the Maybe monad.
Computations are actions that may produce a value or fail.
The return function yields a successful computation, while >>=
sequences two subcomputations, failing on the first error.
| Constructors | | Instances | |
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Transform the computation inside a MaybeT.
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Lifting other operations
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Lift a callCC operation to the new monad.
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Lift a catchError operation to the new monad.
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Lift a listen operation to the new monad.
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Lift a pass operation to the new monad.
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Produced by Haddock version 2.6.1 |