alaF and foldMap

Main.purs

module Main where

import Prelude

import Data.Foldable (foldMap, sum)
import Data.List (List)
import Data.List.Lazy (replicate, toUnfoldable)
import Data.Monoid.Additive (Additive(..))
import Data.Newtype (alaF)
import Data.Rational (Ratio, (%))
import Data.Tuple (Tuple(..), uncurry)
import Effect (Effect)
import Effect.Class.Console as Console

newtype RatioInt = RatioInt (Ratio Int)
derive newtype instance Semiring RatioInt
derive newtype instance Show RatioInt

foldTuples :: List (Tuple Int Int) -> RatioInt
foldTuples = foldMap `alaF Additive` (RatioInt <<< uncurry (%))

foldTuples' :: List (Tuple Int Int) -> RatioInt
foldTuples' = sum <<< map (RatioInt <<< uncurry (%))

main :: Effect Unit
main = do
  let 
    tuples = toUnfoldable (replicate 1_000_000 (Tuple 1 2))
  
  Console.time "a"
  Console.logShow (foldTuples tuples)
  Console.timeEnd "a"
  
  Console.time "b"
  Console.logShow (foldTuples' tuples)
  Console.timeEnd "b"