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

divarvel

console.log("\033[39mRunning tests…");
function assertEquals(actual, expected, description) {
    if(typeof(actual) === "undefined") {
        console.error("\033[31m" + description + " not implemented\033[39m");
    } else {
        if(actual !== expected) {
            console.error("\033[31m" + description + " failed, expected " + expected + ", got " + actual + "\033[39m");
        } else {
            console.log(description + " \033[32m ok\033[39m");
        }

paulirish

/* bling.js */

window.$ = document.querySelectorAll.bind(document);

Node.prototype.on = window.on = function (name, fn) {
  this.addEventListener(name, fn);
}

NodeList.prototype.__proto__ = Array.prototype;

chpatrick

{-# LANGUAGE MagicHash, TupleSections, TemplateHaskell #-}

module Data.Vector.Storable.Bake(bake, unsafeFromAddrLen) where

import Data.Typeable
import qualified Data.Vector.Storable as VS
import Foreign
import GHC.Prim
import GHC.Ptr
import Language.Haskell.TH

CMCDragonkai

Numeric Typeclasses - How numbers work!

Numbers in Haskell are typed of course. They also exist as instances of a numeric typeclass hierarchy. I was confused with converting and working with numbers of different types, and not being sure which functions were polymorphic and could work with different numeric types. So I created a little diagram. Do note that the typeclass hierarchy of Haskell actually does somewhat follow the hierarchy of numbers in Math.

calstad

Quick List of Resources for Topological Data Analysis with Emphasis on Machine Learning

This is just a quick list of resourses on TDA that I put together for @rickasaurus after he was asking for links to papers, books, etc on Twitter and is by no means an exhaustive list.

Survey Papers

Both Carlsson's and Ghrist's survey papers offer a very good introduction to the subject

• Topology and Data by Gunnar Carlsson
• Barcodes: The Persistent Topology of Data by Robert Ghrist

Other Papers and Web Resources

• Extracting insights from the shape of complex data using topology A good introductory paper in Nature on the Mapper algorithm.

jtobin

{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE UndecidableInstances #-}

import Prelude hiding (succ)

newtype Fix f = Fix (f (Fix f))

deriving instance (Show (f (Fix f))) => Show (Fix f)

Teggy

{-# LANGUAGE TypeSynonymInstances #-}

import Data.Monoid
import Data.Maybe

-- How much water does a "histogram" hold?
--
-- Inspired by Guy Steele's talk "Four Solutions to a Trivial Problem"
-- https://www.youtube.com/watch?v=ftcIcn8AmSY

bastman

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

evincarofautumn

Thoughts on an InlineDoBind extension

An expression beginning with a left arrow (<-) inside a do block statement is desugared to a monadic binding. This is syntactically a superset of existing Haskell, including extensions. It admits a clean notation that subsumes existing patterns and comes with few downsides.

Examples

do
  f (<- x) (<- y)
-- ===