paf31

FreeAp f is a Comonad

While thinking about comonads as spaces and Day convolution, I realized an interesting thing. The free applicative functor generated by a comonad f is also a comonad.

The free applicative can be defined in a few different ways, but I like to define it like this:

data FreeApplicative f a = Pure a | Free (Day f (FreeApplicative f) a)

ChrisPenner

module LispParser where
import Text.Megaparsec
import Text.Megaparsec.String
import Text.Megaparsec.Lexer  hiding (space)

data E=L[E]|S String|N Integer deriving Show
e=(char '('*>(L<$>some e)<*char ')'<|>N<$>integer<|>S<$>some letterChar)<*space::Parser E

winterland1989

{-# LANGUAGE CPP #-}
{-# LANGUAGE MagicHash #-}

-- | This module provide fast memchr implemented with ghc primitives.
--
-- http://lemire.me/blog/2017/01/20/how-quickly-can-you-remove-spaces-from-a-string/
-- https://graphics.stanford.edu/~seander/bithacks.html
-- https://jameshfisher.github.io/2017/01/24/bitwise-check-for-zero-byte.html
--
--

danidiaz

Papers

Time clock and the ordering of events in a distributed system

Consensus on Transaction Commit

An empirical study on the correctness of formally verified distributed systems

Byzantizing Paxos by Refinement

tonymorris

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE DeriveFunctor #-}

import Control.Lens
import Prelude hiding (readFile, writeFile, print)
import qualified Prelude as Prelude(readFile, writeFile, print)

mrkgnao

{-# LANGUAGE Arrows                 #-}
{-# LANGUAGE ConstraintKinds        #-}
{-# LANGUAGE FlexibleContexts       #-}
{-# LANGUAGE FlexibleInstances      #-}
{-# LANGUAGE GADTs                  #-}
{-# LANGUAGE InstanceSigs           #-}
{-# LANGUAGE LambdaCase             #-}
{-# LANGUAGE MultiParamTypeClasses  #-}
{-# LANGUAGE RankNTypes             #-}
{-# LANGUAGE ScopedTypeVariables    #-}

danidiaz

• Viewshed, Viewshed analysis

• Isovist

• Field of view

• Terminating vista

• Preferred walking speed

treeowl

{-# LANGUAGE DataKinds, TypeFamilies, TypeOperators, GADTs,
      ScopedTypeVariables, TypeOperators #-}

-- | Type-level natural numbers and singletons, with proofs of
-- a few basic properties.

module BasicNat (
    -- | Type-level natural numbers
    Nat (..)
  , type (+)

reinh

-- The meta-circular interpreter from section 5 of Reynolds's Definitional
-- Interpreters for Higher Order Programming Languages
-- (http://www.cs.uml.edu/~giam/91.531/Textbooks/definterp.pdf)

data EXP
  = CONST Const
  | VAR Var
  | APPL Appl
  | LAMBDA Lambda
  | COND Cond

dariusf

class Files {
  static void read(File<Open> file) {}
  static File<Open> open(File<Closed> file) {
    return null;
  }
  static File<Closed> close(File<Open> file) {
    return null;
  }
}