int-index

{-# LANGUAGE TemplateHaskell #-}
module Application where

import Control.Lens

import Snap.Snaplet
import Snap.Snaplet.Heist (Heist, HasHeist(..))

data App = App
    { _heist :: Snaplet (Heist App)

int-index

module Dynamic where

import Control.Applicative
import Data.Dynamic

please = maybe (error "dynamic typing is bad :(") toDyn

pleaseApp2 :: (Rational -> Rational -> Rational)
           -> (Dynamic -> Dynamic -> Dynamic)
pleaseApp2 f a b = please $ f <$> fromDynamic a <*> fromDynamic b

int-index

{-# LANGUAGE PartialTypeSignatures #-}
module Main where

data I a = I a
instance Functor I where
    fmap f (I a) = I (f a)

newtype B t a = B a
instance Functor (B t) where
    fmap f (B a) = B (f a)

int-index

GHCi, version 7.10.3: http://www.haskell.org/ghc/  :? for help
Prelude> :l M.hs
[1 of 1] Compiling Main             ( M.hs, interpreted )
Ok, modules loaded: Main.
*Main> 

int-index

{-# LANGUAGE NoImplicitPrelude, GADTs, DataKinds, PolyKinds, FlexibleInstances #-}

import Data.Monoid
import Control.Category

-- A monoid gives a rise to a single-object category.
newtype M m (a :: ()) (b :: ()) = M m

instance Monoid m => Category (M m) where
  id = M mempty

int-index

[1 of 1] Compiling Main             ( fieldtype.hs, fieldtype.o )

fieldtype.hs:19:27: error:
    • Expected kind ‘Fin (FieldCount T)’,
        but ‘'FZ’ has kind ‘Fin ('S n0)’
    • In the second argument of ‘FieldType’, namely ‘FZ’
      In the type instance declaration for ‘FieldType’

fieldtype.hs:20:28: error:
    • Expected kind ‘Fin (FieldCount T)’,

int-index

{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances,
             TypeOperators, UndecidableInstances #-}
{-# LANGUAGE RankNTypes, ScopedTypeVariables, ConstraintKinds #-}

import Data.Constraint
import Data.Constraint.Forall

class C1 a b
class C2 a b
instance C1 a b => C2 a b

int-index

{-# LANGUAGE RankNTypes, ScopedTypeVariables, FlexibleContexts #-}

import Control.Monad.Reader
import Data.Reflection
import Data.Tagged
import Data.Proxy

f :: Reader String Int
f = do
  a <- ask

int-index

Keybase proof

I hereby claim:

• I am int-index on github.
• I am int_index (https://keybase.io/int_index) on keybase.
• I have a public key ASDdpc-5-1Z79PVP06_HBtD5DQ-q0TkrX3nyQs7cIvSEFQo

To claim this, I am signing this object:

int-index

{-# LANGUAGE GeneralizedNewtypeDeriving, FlexibleInstances, OverloadedStrings, UndecidableInstances #-}

import Control.Monad.Logger
import Control.Monad.Trans
import Control.Monad.Trans.Identity
import Data.Coerce

class Monad m => MonadFoo m where
  foo :: m ()