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{-# LANGUAGE RankNTypes #-}
import Control.Monad.Cont (MonadIO)

-- Comparison: How simplified subsumption interacts with newtype and with type aliases

-- example with type alias:

type Foo a = forall m. MonadIO m => m a

foo :: forall m a. MonadIO m => Int -> m a

cjay

/* 
For use with the Stylus browser extension, since Dark Reader is slow on the giant single page spec.
*/

html,
body,
input,
textarea,
select,
button {

cjay

{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE NoStarIsType #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ConstraintKinds #-}

cjay

	Mon Jan 21 18:31 2019 Time and Allocation Profiling Report  (Final)

	   day14b +RTS -p -RTS

	total time  =       18.53 secs   (18528 ticks @ 1000 us, 1 processor)
	total alloc = 46,140,950,288 bytes  (excludes profiling overheads)

COST CENTRE              MODULE                            SRC                                                    %time %alloc

generate.gen             Main                              src/Day14b.hs:(83,3)-(91,34)                            24.1   36.0

cjay

List folds in Haskell from a use case oriented perspective

Since the definitions in Data.Foldable are too generic, here are list-specific ones:

-- foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn
foldl :: (b -> a -> b) -> b -> [a] -> b
foldl f z []     = z
foldl f z (x:xs) = let z' = z `f` x
                   in foldl f z' xs