monad-classes: more flexible mtl

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Versions [RSS]	0.3, 0.3.0.1, 0.3.1.0, 0.3.1.1, 0.3.2.0, 0.3.2.1, 0.3.2.2
Dependencies	base (>=4.7 && <5), ghc-prim, mmorph (>=1.0.3), monad-control (>=1), peano (>=0.1), reflection (>=1.4), transformers (>=0.2), transformers-base (>=0.4.2), transformers-compat (>=0.3.1) [details]
Tested with	ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.2
License	MIT
Author	Roman Cheplyaka <roma@ro-che.info>
Maintainer	M Farkas-Dyck <strake888@gmail.com>
Category	Control
Home page	https://github.com/strake/monad-classes.hs
Uploaded	by MatthewFarkasDyck at 2018-05-07T04:02:44Z
Distributions	NixOS:0.3.2.2
Reverse Dependencies	7 direct, 0 indirect [details]
Downloads	5324 total (21 in the last 30 days)
Rating	2.0 (votes: 1) [estimated by Bayesian average]
Your Rating	λ λ λ
Status	Docs available [build log] Last success reported on 2018-05-07 [all 1 reports]

See this series of articles for the detailed description and motivation.

This is a more flexible version of mtl, the monad transformers library.

You can have many layers of e.g. state transformers in your stack, and you don't have to explicitly lift your gets and puts, as soon as different state transformers carry different types of states.

Example:
```
a :: (MonadState Bool m, MonadState Int m) => m ()
a = do
  put False -- set the boolean state
  modify (+ (1 :: Int)) -- modify the integer state
```
mtl requires Θ(n²) instances (like MonadReader e (StateT s m)); monad-classes requires only Θ(n) of them (where n is the number of different transformer types).

If you'd like to define your own monad-classes-style class, you have to write much less boilerplate code.