chrisdone

Duet's folds example

Duet has this folding example:

data List a = Nil | Cons a (List a)
foldr = \f z l ->
  case l of
    Nil -> z
    Cons x xs -> f x (foldr f z xs)

chrisdone

-- | Execute the steps.
execute :: [SomeStep] -> RIO MainEnv ()
execute steps = do
  resources <- newIORef mempty
  mapRIO
    (\MainEnv {logger} -> ExecuteEnv {logger = logger . ExecuteLog, resources})
    (mapM_ executeSomeStep steps)

chrisdone

> :set -XOverloadedStrings
> :set -XTemplateHaskell

> import Language.Haskell.TH
> $(bsToExp "Hello, World" >>= stringE . show)
"AppE (VarE GHC.IO.Unsafe.unsafePerformIO) (AppE (AppE (VarE Data.ByteString.Unsafe.unsafePackAddressLen) \
\(LitE (IntegerL 12))) (LitE (StringPrimL [72,101,108,108,111,44,32,87,111,114,108,100])))"
> 

> :set -ddump-splices

chrisdone

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeFamilies #-}

import           Data.Bifunctor

chrisdone

{-# LANGUAGE ScopedTypeVariables #-}

module Data.Graph.Shuffle where

-- | Shuffle a graph into a randomly sorted list, preserving
-- topological order.

{-

> quickCheckWith stdArgs {maxSuccess=10000} prop_identity

chrisdone

{-# LANGUAGE PartialTypeSignatures #-}
module StableShuffle where

import           Control.Monad
import           Control.Monad.Random
import           Data.Bifunctor
import           Data.List
import qualified Data.Map.Strict as M
import           Data.Maybe
import           Data.Ord

chrisdone

{-# LANGUAGE PartialTypeSignatures #-}
module StableShuffle where

import           Control.Monad
import           Control.Monad.Random.Class
import           Data.List
import qualified Data.Map.Strict as M
import           Data.Maybe
import           Data.Ord
import           System.Random.Shuffle

chrisdone

chris@precision:~/Work/chrisdone/prj$ stack build -v
Version 2.2.0, Git revision 896869ee79d82e3bd9bead30d610ac2bf580cd99 (dirty) (7790 commits) PRE-RELEASE x86_64 hpack-0.31.2
2019-07-31 14:16:17.668130: [debug] Checking for project config at: /home/chris/Work/chrisdone/prj/stack.yaml
2019-07-31 14:16:17.668320: [debug] Loading project config file stack.yaml
2019-07-31 14:16:17.674494: [debug] SELECT COUNT(*) FROM "last_performed" WHERE ("action"=?) AND ("timestamp">=?); [PersistInt64 1,PersistUTCTime 2019-07-30 13:16:17.674439 UTC]
2019-07-31 14:16:17.675171: [debug] Using package location completions from a lock file
2019-07-31 14:16:17.877293: [debug] Asking for a supported GHC version
2019-07-31 14:16:17.877678: [debug] Installed tools: 
 - ghc-8.2.2
 - ghc-8.6.3

chrisdone

chris@precision:~/Work/chrisdone/prj$ stack build -v
Version 2.2.0, Git revision 896869ee79d82e3bd9bead30d610ac2bf580cd99 (dirty) (7790 commits) PRE-RELEASE x86_64 hpack-0.31.2
2019-07-31 13:32:31.396846: [debug] Checking for project config at: /home/chris/Work/chrisdone/prj/stack.yaml
2019-07-31 13:32:31.397084: [debug] Loading project config file stack.yaml
2019-07-31 13:32:31.405902: [debug] SELECT COUNT(*) FROM "last_performed" WHERE ("action"=?) AND ("timestamp">=?); [PersistInt64 1,PersistUTCTime 2019-07-30 12:32:31.40582 UTC]
2019-07-31 13:32:31.406606: [debug] Using package location completions from a lock file
2019-07-31 13:32:31.568532: [debug] Asking for a supported GHC version
2019-07-31 13:32:31.569087: [debug] Installed tools: 
 - ghc-8.2.2
 - ghc-8.6.3

chrisdone

{-

> :t $$(named [|| map ||])
$$(named [|| map ||])
  :: TypedName
       ((ghc-prim-0.5.3:GHC.Types.Any -> ghc-prim-0.5.3:GHC.Types.Any)
        -> [ghc-prim-0.5.3:GHC.Types.Any]
        -> [ghc-prim-0.5.3:GHC.Types.Any])
> $$(named [|| map ||])
TypedName GHC.Base.map