Icelandjack

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Yoneda Intuition from Humble Beginnings

Let's explore the Yoneda lemma. You don't need to be an advanced Haskeller to understand this. In fact I claim you will understand the first section fine if you're comfortable with map/fmap and id.

I am not out to motivate it, but we will explore Yoneda at the level of terms and at the level of types.

tfausak

# The GHC team announced the first release candidate for the 8.2.2 release of
# GHC over the weekend: https://mail.haskell.org/pipermail/ghc-devs/2017-October/014777.html
#
# This is an example `stack.yaml` file that you can use to try out the release
# candidate. Save this file in your current directory and run `stack setup`.
# After that you should be able to use Stack as normal, including
# `stack exec ghci` and `stack build`.
#
# If for whatever reason you don't want to use Stack, you can download the
# official release tarballs at: https://downloads.haskell.org/~ghc/8.2.2-rc1/

taktoa

with builtins;

rec {
  pkgs = import <nixpkgs> {};

  testGHC = pkgs.haskellPackages.ghcWithPackages (p: with p; [
    base base-orphans bifunctors comonad contravariant distributive
    tagged transformers
  ]);

proger

helper = /tmp/.build-secrets-helper
# path to the ephemeral store
store = /run/sproxy-sink/store
aes_path = secrets/aes-password
gpg_key = C4DECDD2

secrets-encrypted: paths-sproxy.nix $(aes_path)
	tar c $(store) | openssl aes-256-cbc -pass file:secrets/aes-password -a > $@

paths-sproxy.nix: ./sproxy-config.nix

puffnfresh

-- Idris translation of copumpkin's Agda code:
-- https://gist.github.com/copumpkin/8758586

-- Proves that List reverse is completely specified by:
-- 1. f [] = []
-- 2. f [x] = [x]
-- 3. f (xs ++ ys) = f ys ++ f xs

reverse' : List a -> List a
reverse' [] = []

mrb

• Abramsky and Jung "Domain Theory" http://www.cs.bham.ac.uk/~axj/pub/papers/handy1.pdf
• Appel, Andrew "Modern Compiler Implementation in ML"
• Cousot, Patrick "Abstract Interpretation Based Formal Methods and Future Challenges" http://www.di.ens.fr/~cousot/publications.www/Cousot-LNCS2000-sv-sb.pdf
• Darais, Might, and Van Horn "Galois Transformers and Modular Abstract Interpreters" http://arxiv.org/pdf/1411.3962v1.pdf
• Davey and Priestley, "Introduction To Lattices and Order"
• Friedman and Mendhekar, "Using an Abstracted Interpreter to Understand Abstract Interpretation" http://www.cs.indiana.*du/l/www/classes/b621/abiall.pdf
• Friedman and Wand, "Essentials of Programming Languages"
• Jones and Nielson, "Abstract Interpretation: a Semantics-Based Tool for Program Analysis" http://se.inf.ethz.ch/courses/2014b_fall/sv/reading/jones-nielson.pdf
• Livshits, Sridharan, Smaragdakis, et. al. "In Defense of Soundiness: A Manifesto" http://cgi.di.uoa.gr/~smaragd/Soundiness-CACM.pdf
• Might, Matt "Writing an inte

evincarofautumn

#include <iostream>
#include <numeric>
#include <vector>
using namespace std;

// In Haskell, the Monoid typeclass is parameterised by only a type. Such a
// definition requires “newtype hacks” to produce different monoids on the same
// type. This definition is parameterised by both the type and the function, and
// as such can be used to define different monoids on the same type without any
// interference.

chrisdone

Typing Haskell in Haskell

MARK P. JONES

Pacific Software Research Center

Department of Computer Science and Engineering

Oregon Graduate Institute of Science and Technology

kachayev

Parsing CSS file with monadic parser in Clojure

Inspired by "Parsing CSS with Parsec".

Just quick notes and code that you can play with in REPL.

By @kachayev

0. Intro

supki

{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE EmptyCase #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TypeFamilies #-}