Gabriella439

Awake Security Haskell Livestream

Who

Awake Security will be livestreaming a periodic 1-on-1 teaching session on Twitch. The subject of this session will always be one of our engineers teaching another one of our engineers how to do accomplish a practical task in Haskell while remote attendees watch, comment, and ask questions.

Gabriella439

{-# LANGUAGE DeriveAnyClass    #-}
{-# LANGUAGE DeriveGeneric     #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}

import Data.ByteString (ByteString)
import Data.Default.Class (Default(..))
import GHC.Generics (Generic)
import Network.Connection (ConnectionParams(..))
import Options.Generic (ParseRecord)

Gabriella439

These are my rough notes when preparing for a Haskell livestream that I thought would be worth sharing. Some things are general comments on contributing to the open source ecosystem whereas other notes are specific to the stream (e.g. Haskell and the streamly package)

How things look from a maintainer's point of view (for highly active projects):

• Reactive

As projects become more active the maintainer's "inbox" gets pretty large. A

Gabriella439

* Importance of category theory
    * Answers the question: "What is a *timeless* API?"
        * What does "timeless" mean?
            * Likely to still be relevant years from now
            * Likely to be low maintenance (since unlikely to change)
            * Less likely to be subject to controversy or discussion ("obvious")
    * Examples:
        * Everything Haskell's typeclassopedia (except maybe `Foldable`)
        * Categories / Monoids
            * `(.)` / `id`

Gabriella439

⊢ :let List/generate = https://prelude.dhall-lang.org/List/generate

List/generate : ∀(n : Natural) → ∀(a : Type) → ∀(f : Natural → a) → List a

⊢ List/generate 10

  λ(a : Type)
→ λ(f : Natural → a)
→ [ f 0, f 1, f 2, f 3, f 4, f 5, f 6, f 7, f 8, f 9 ]

Gabriella439

Programming Language Checklist by Colin McMillen, Jason Reed, and Elly Fong-Jones, 2011-10-10.

You appear to be advocating a new:

• functional
• imperative
• object-oriented
• procedural
• stack-based

Gabriella439

let
  nixpkgs = builtins.fetchTarball {
    url    = "https://github.com/NixOS/nixpkgs/archive/f3fc2f3326a23797b2c95297e68ed8e8de2a95e6.tar.gz";
    sha256 = "0wsplccl8bv522zh3y8affacw9pmzsxm18i5hdgz78gxh8m7k933";
  };

  nixos = import "${nixpkgs}/nixos" {
    system = "x86_64-linux";

    configuration = { pkgs, ... }:

Gabriella439

module ConcurrentMap where

import Control.Concurrent.STM.TVar (TVar)
import Control.Concurrent.STM (STM)
import Data.Hashable (Hashable)
import Data.HashMap.Strict (HashMap)
import Data.Vector (Vector)

import qualified Control.Concurrent.STM.TVar as TVar
import qualified Data.Hashable               as Hashable

Gabriella439

{-# LANGUAGE RankNTypes #-}

import Prelude hiding (Bool(..))

type Bool = forall a . a -> a -> a

false :: Bool
false = \true_ false_ -> false_

true :: Bool

Gabriella439

{-# LANGUAGE DeriveGeneric  #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeApplications #-}

module Main where

import Data.Csv (FromField, FromNamedRecord)
import Data.Text (Text)
import Data.Map (Map)