mtl-uplift: Lift substacks of monad transformer stacks

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Lift substacks of monad transformer stacks.

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Dependencies base (>=4.12 && <4.15), mtl (>=2.2) [details]
License MIT
Copyright 2020 Samuel Schlesinger
Author Samuel Schlesinger
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Uploaded by sgschlesinger at 2020-09-27T20:09:13Z
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Last success reported on 2020-09-27 [all 1 reports]


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Uplift entire substacks of monad transformer stacks, boilerplate free!

Many industry Haskell programmers are all too familiar with code like:

lift . lift . lift . lift . lift . lift . lift . lift . lift . lift . lift . lift . lift $ do

This may or may not be an exaggeration. Now, we can just write the much less visually annoying:

uplift @TopOfSubstackT $ do

This relieves the programmer from having to do any bookkeeping about what level of their greater stack their substack lives at, but just to know which monad tops it. Beyond that, if we transform our stack, with the old code we would potentially have to modify the number of calls to lift, but now, as long as we still want to uplift a substack with the same top, we don't have to. Isn't that uplifting?