cmk

deciban

The following table lists a number of rare events, arranged on a deciban scale. The deciban is a logarithmic unit — much like the decibel or the Richter scale — introduced by Alan Turing for expressing probabilities. It is a tenth of a ban, which is also known as the base-10 log-odds.

Please note that these are only rough estimates for the purpose of providing intuition for the relative likelihood of various rare events. Many are based on population averages, and do not apply to you personally. As always, keep the above comic in mind ;)

decibans	event

cmk

{-# LANGUAGE FlexibleContexts        #-}
{-# LANGUAGE TupleSections        #-}
{-# LANGUAGE RankNTypes        #-}

import Data.Bifunctor
import Data.Bifoldable
import Data.Bifunctor.Join
import Data.Biapplicative
import Data.Bitraversable

cmk

Reddit discussion.

Disclaimer 1: Type classes are great but they are not the right tool for every job. Enjoy some balance and balance to your balance.

Disclaimer 2: I should tidy this up but probably won’t.

Disclaimer 3: Yeah called it, better to be realistic.

Type classes are a language of their own, this is an attempt to document features and give a name to them.

cmk

Verifying my Blockstack ID is secured with the address 1JafhKfXbBynoUfwCLJ1r9u4ymdyaC5N9c https://explorer.blockstack.org/address/1JafhKfXbBynoUfwCLJ1r9u4ymdyaC5N9c

cmk

-- | A 'Validator a b' is in particular a '(Applicative f, Choice p) => p a (f b)'.
type Validator a b = a -> Validation ValidationErrors b

-- | Lift a 'Getting (Maybe a) s (Maybe a)' into a 'Prism'. This should only be used if the
-- target domain type is a 'Maybe b'. 
--
-- Note that error messages from 'Validator's consumed in this way are preserved.
--
-- @
-- 'validating' :: Getting (Maybe a) s (Maybe a) -> Validator a b -> Validator s (Maybe b)

cmk

#!/usr/bin/env stack
-- stack --resolver lts-11.10 script
import Control.Monad.Trans.Class
import Control.Monad.IO.Class
import Data.Functor.Identity

newtype ReaderT r m a = ReaderT { runReaderT :: r -> m a }

instance Functor m => Functor (ReaderT r m) where
  fmap f (ReaderT rma) = ReaderT $ fmap f . rma

cmk

Verifying my Blockstack ID is secured with the address 1Ati9McJQVKAzatFb6JhKE957xvE2tiN6Q https://explorer.blockstack.org/address/1Ati9McJQVKAzatFb6JhKE957xvE2tiN6Q

cmk

{-# LANGUAGE  RankNTypes, FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
module Free where

import Control.Monad.IO.Class
import Data.IORef
import Control.Applicative
import Control.Monad
import Data.Maybe (fromMaybe)
import qualified Control.Monad.Trans.State as ST
import qualified Data.Map as M

cmk

Free Monad + Interpreter Pattern

It's like creating the front end and back end of a compiler inside Haskell without the need of Template Haskell!

Write your DSL AST as a Free Monad, and then interpret the monad any way you like.

The advantage is that you get to swap out your interpreter, and your main code

cmk

--Number of commits for libraries of interest during 2015–09–30 ~ 2016–09–30:

SELECT date, idname.repo_name AS repo_name, num_commits
FROM
(SELECT 
  DATE(created_at) AS date, 
  repo.id,
  SUM(INTEGER(JSON_EXTRACT(payload, '$.size'))) AS num_commits
FROM
  (TABLE_DATE_RANGE([githubarchive:day.],