# unlift

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Typeclass for monads that can be unlifted to arbitrary base monads:

```haskell
class (MonadBase b m) => MonadUnlift b m
  where
    withRunInBase :: ((forall a . m a -> b a) -> b x) -> m x
```

This typeclass is helpful when writing code that is polymorphic over the base
monad, so later you can select a different base monad for each specific use-case.

Common usages include:

1. Concurrent testing with [dejafu](https://hackage.haskell.org/package/dejafu).
2. Working with code over polymorphic [PrimMonad](https://hackage.haskell.org/package/primitive-0.7.1.0/docs/Control-Monad-Primitive.html#t:PrimMonad).