Julian Fell jtfell

## SimpleLens.hs
{-# LANGUAGE RankNTypes #-}

import Data.Functor.Const
import Data.Functor.Identity

type SimpleLens s a = forall f. Functor f => (a -> f a) -> s -> f s

view :: SimpleLens s a -> s -> a
view l = getConst . l Const

## scottish-tablet-recipe.md

      
              1 file
            
          
              0 forks
            
          
              0 comments
            
          
              4 stars
            
          
                colingourlay
                / scottish-tablet-recipe.md
            
            
              Last active
              March 3, 2023 05:39
            
              
                Scottish Tablet Recipe
              
          
    Scottish Tablet


Preparation time: 40 minutes
Total time: 3 hours
Makes: ~50 portions

Ingredients


1kg caster sugar
250g butter
	{-# LANGUAGE RankNTypes #-}

	import Data.Functor.Const
	import Data.Functor.Identity

	type SimpleLens s a = forall f. Functor f => (a -> f a) -> s -> f s

	view :: SimpleLens s a -> s -> a
	view l = getConst . l Const