mstksg

andThen :: (s -> IO (a, s)) -> (s -> IO (b, s)) -> (s -> IO (b, s))

andThenWith :: (s -> IO (a, s)) -> (a -> (s -> IO (b, s))) -> (s -> IO (b, s))




-- type synonym:
--
-- > type MIOS s a = s -> IO (s, a)

mstksg

{-# LANGUAGE Arrows #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE NoMonomorphismRestriction #-}

module Main (main) where

import Control.Wire
import FRP.Netwire.Move
import Control.Arrow
import Prelude hiding ((.), id, mapM_)

mstksg

PID Controller: A comparison of approaches

And a case for a compositional, denotative, and locally stateful style.

High Level Description

mstksg

{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE StandaloneDeriving #-}

mstksg

import System.Random
import Control.Monad.Random
import Control.Monad

metroStep :: (RandomGen g) => (Double -> Double) -> Double -> Double -> Rand g Double
metroStep p step x = do
  dx <- getRandomR (-step, step)
  let
    newx = x + dx
    p0 = p x

mstksg

{-# LANGUAGE FlexibleContexts             #-} 
{-# LANGUAGE GADTs                        #-} 
{-# LANGUAGE QuasiQuotes                  #-} 
{-# LANGUAGE TemplateHaskell              #-} 
{-# LANGUAGE TypeFamilies                 #-} 
{-# LANGUAGE TypeSynonymInstances         #-} 
{-# LANGUAGE GeneralizedNewtypeDeriving   #-} 
{-# LANGUAGE EmptyDataDecls               #-} 
{-# LANGUAGE OverloadedStrings            #-}

mstksg

import Data.Maybe (isJust)

assert :: Bool -> Maybe ()
assert True = Just ()
assert False = Nothing

checkAssertions :: Maybe () -> Bool
checkAssertions = isJust

checkMatch :: Person -> Person -> Bool

mstksg

-- test1.hs
-- No dead code: compiles to 1.22M executable
--               with stripped .o 1320 byes
--               .o file md5sum: 35ccd1647c772a5757fba3ae8bfa6542

main :: IO ()
main = getLine >>= print

-- test2.hs
-- With dead code: compiles to 1.22M executable

mstksg

Keybase proof

I hereby claim:

• I am mstksg on github.
• I am mstksg (https://keybase.io/mstksg) on keybase.
• I have a public key whose fingerprint is 1BB5 2738 56F8 1236 7977 2D4F 7250 9247 67D5 7F1C

To claim this, I am signing this object:

mstksg

{-# language DataKinds, PolyKinds, ScopedTypeVariables, UndecidableInstances,
    FlexibleInstances, FlexibleContexts, GADTs, TypeFamilies, RankNTypes,
    LambdaCase, TypeOperators, ConstraintKinds #-}

import GHC.TypeLits
import Data.Proxy
import Data.Singletons.Prelude
import Data.Singletons.Decide
import Data.Constraint