lspitzner

kinds and their inhabitants

*
  inhb: Bool, Int, Void, ..
  clss: Num, Show, Eq, Typeable, Monoid, Semigroup, ..
  
* -> *
  inhb: [], Maybe, Tree, ZipList, MVar, ST, IO, ..
  clss: Functor, Monad, Foldable, Traversable, GMonoid, GShow, ..

lspitzner

my sublime setup for haskell includes:

• SublimeHaskell, but with most features disabled. mostly for syntax highlighting. (as was pointed out, it is sufficient to grab the *theme file and omit the rest of the plugin. And even that is optional.)
• for auto-formatting:
  • this (slightly modified) external-command plugin: https://github.com/lspitzner/SublimeExternalCommand
  • brittany (installed so that is on path)
  • the below keybind (you can open the user keybindings in sublime and merge the below)
  • you can either select some function and reformat that by pressing f9, or select nothing (whole file gets formatted)
• for quick compilation feedback:

lspitzner

-- | Mask an event. The first parameter is the "masking event" that masks when
-- input events are forwarded to output events. The behavior constructed by
-- `stepper False mE` defines the masking period: When True, events can pass,
-- otherwise they are accumulated internally and can not pass.
-- As soon as the masking event switches from True to False, all accumulated
-- events get triggered simultaneously.
--     mask    *************         *******
--          ***             *********       *******
--     
--     eIn  v1   v2   v3             v4     v5

lspitzner

# if you run this 5+ times, you will get rate-limited.
node fetch-comments.js
node process-comments.js > comments_.txt
cat comments_.txt | sed 's/#/\\#/g' | pandoc -f markdown -o comments.html
# Plus manual embedding into a html with <meta http-equiv="Content-Type" content="text/html; charset=utf-8">.
# Or serve with appropriate Content-Type.

lspitzner

newtype ContCatchT r e m a =
    ContCatchT { getContCatchT :: ((e -> m r) -> a -> m r) -> (e -> m r) -> m r }

instance Functor (ContCatchT r e m) where
    fmap f (ContCatchT k) =
        ContCatchT $ \c1 c2 -> k (\c3 -> c1 c3 . f) c2

instance Applicative (ContCatchT r e m) where
    pure x = ContCatchT $ \c1 c2 -> c1 c2 x
    ContCatchT cf <*> ContCatchT cx = ContCatchT

lspitzner

class A a where
  a :: Monad m => a -> m a

instance A Int where
  a = pure

newtype MyNewtype = MyNewtype Int deriving A
-- ^ 
-- error:
--    • Couldn't match representation of type ‘m Int’

lspitzner

createLimitedList
  :: (MonadHold t m, MonadFix m, Adjustable t m)
  => IntMapS.Key
  -> Event t (m ())
  -> m ()
createLimitedList elemLimit e = do
  let f a (_, i) =
        ( PatchIntMap $ IntMapS.fromList [(i - elemLimit, Nothing), (i, Just a)]
        , i + 1
        )

lspitzner

old-style	new-style
install --only-dependencies	part of new-build
install path-to-local-dir	add a ./cabal.project file, add your local dependency, then use new-build (cabal.project syntax is described in the announcement)
install path-to-local-sdist	does not exist yet
install remote-package-uri	does not exist yet
install [--bindir=..]	does not exist (yet)
configure	new-configure
build	(part of) new-build
clean	does not exist yet; you have to remove ./dist-newstyle/ and ./cabal.project.local by hand, and potentially ./dist/ as well, i may have observed that it got touched by new-build (not sure, really). This needs to be done for each package referenced from the cabal.project as well.

lspitzner

#!/bin/bash

ls -1 stackage | xargs -I{} bash -c "find \"stackage/{}\" -type f -name \"*.hs\" -o -name \"*.lhs\"\
  | xargs grep -h \"^import\" \
  | grep \" as \" \
  | sed \"s/ \+as//\" \
  | sed \"s/^import \+\(qualified \+\)\?//\" \
  | sort \
  | uniq \
  " \

lspitzner

-- the basic idea, without mentioning "comonad":

data RecEvent t a = RecEvent
  { rec_current :: a
  , rec_next :: R.Event t (RecEvent t a)
  }

foldRecEvent :: R.Reflex t => RecEvent t a -> R.PushM t (R.Dynamic t a)
foldRecEvent r1@(RecEvent _ e1) = do
  e1' <- R.headE e1