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drv =
  pkgs.haskell.lib.addBuildDepends
    (pkgs.haskellPackages.callPackage ./default.nix {})
    (with pkgs; [ docker ])
    ;

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{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE DeriveFunctor #-}

module DynamicReader where

import Control.Monad.Reader (MonadReader(ask, local), ask, ReaderT(ReaderT), runReaderT)

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class HasLoggingRep a where
  toLogEntry :: a -> Text
  
-- ...
where 
  logInfo :: forall a . HasLoggingRep a => a -> IO ()
  logInfo = loggerF logger Info . toLogEntry
-- ...
  someFn response = do
    logInfo response

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module ConstraintsOnFunction (mkLookup) where

type Lookup m = Request -> m Response

mkLookup :: (
  AsSomeError e,
  MonadCatch m,
  MonadError e m,
  MonadIO m,
  MonadResource m) => Lookup m

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someFn :: b -> m a -> m a

someStack :: ActionT e m a
someStack = do
  r <- ask
  info = r ^. getInfo
  lift $ someFn info _

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This guide outlines an approach to overcome some problems with concrete monad stacks and monad composition.

The problem

So we're writing some code in IO, and everything is going great:

doStuff :: IO Int

doStuff = do

sevanspowell

Running Emacs Haskell Tooling in a Nix environment

A guide to setting up the Haskell tooling for Emacs in a Nix environment.

Suggestions/Contact

mail@sevanspowell.net

Configuration

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# Running Emacs Haskell Tooling in a Nix environment

A guide to setting up the Haskell tooling for Emacs in a Nix environment.

## Configuration

### Requirements

You will need the following packages:

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fn
  :: ( Monad m
     , MonadReader r m
     , HasX r m
     , HasY r m
     , HasZ r m
     )
  => m Bool
fn = do
  r <- ask

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• Couldn't match type ‘a’ with ‘a1’
      ‘a’ is a rigid type variable bound by
        the type signature for:
          mogel :: forall a. Show a => a -> (String, a)
        at src/Types.hs:105:1-48
      ‘a1’ is a rigid type variable bound by
        the type signature for:
          b :: forall a1. Show a1 => Maybe a1
        at src/Types.hs:108:5-39
      Expected type: Maybe a1