codo-notation

A notation for comonads, analogous to the do-notation for monads.

Version on this page:0.5.2
LTS Haskell 9.18:0.5.2
Stackage Nightly 2017-12-10:0.5.2
Latest on Hackage:0.5.2
BSD3 licensed and maintained by Dominic Orchard

Module documentation for 0.5.2

A notation for comonads, analogous to the do-notation for monads.

Requires the TemplateHaskell and QuasiQuotes extensions.

Example 1:

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE QuasiQuotes #-}

import Control.Comonad
import Language.Haskell.Codo

foo :: (Comonad c, Num a) => c a -> a
foo = [codo| x => extract x + 1 |]

Example 2:

import Data.Monoid
instance Monoid Double where
       mempty = 0.0
       mappend = (+)

differentiate f = ((f 0.001) - f 0) / 0.001

minima :: (Double -> Double) -> Bool
minima = [codo| f => f'  <- differentiate f
                     f'' <- differentiate f'
                     (extract f' < 0.001) && (extract f'' > 0) |]

Further explanation of the syntax can be found in the following (short) paper: http://www.cl.cam.ac.uk/~dao29/drafts/codo-notation-orchard-ifl12.pdf with a numer of examples.

Further examples can be found here: https://github.com/dorchard/codo-notation.

Used by 1 package:
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