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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 _

sevanspowell

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

[email protected]

Configuration

sevanspowell

# 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