smunix

Typing Haskell in Haskell

MARK P. JONES

Pacific Software Research Center

Department of Computer Science and Engineering

Oregon Graduate Institute of Science and Technology

smunix

With scoped effects, handlers must be a part of the program

It is seductive to imagine that effect handlers in an algebraic effect system are not part of the program itself but metalanguage-level folds over the program tree. And in traditional free-like formulations, this is in fact the case. The Eff monad represents the program tree, which has only two cases:

data Eff effs a where
  Pure :: a -> Eff effs a
  Op :: Op effs a -> (a -> Eff effs b) -> Eff effs b

data Op effs a where

smunix

DCPU-16 Specification
Copyright 1985 Mojang
Version 1.7



=== SUMMARY ====================================================================

* 16 bit words
* 0x10000 words of ram

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newtype Fn a = Fn {unFn :: a -> a}

instance Semigroup (Fn a) where 
  (<>) (Fn a) (Fn b) = Fn (b . a) 
 
import Control.Monad
import Data.Foldable (fold)
import Data.Monoid (appEndo)
import Hedgehog

smunix

image: nixpkgs/cachix-flakes:nixos-20.03

build:
  before_script:
    - mkdir -p /etc/nix
    - echo "experimental-features = nix-command flakes ca-references recursive-nix" >> /etc/nix/nix.conf
    - cachix use numtide
    - nix path-info --all > /tmp/store-path-pre-build
  script:
    - nix flake check

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{ lib, config, pkgs, ... }:

with lib;

{
  options.v4l2 = mkEnableOption "Enable the confguration to use the reflex as a webcam";
  config = mkIf config.v4l2 {
    # 20.03: v4l2loopback 0.12.5 is required for kernel >= 5.5
    # https://github.com/umlaeute/v4l2loopback/issues/257

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import           Data.Function                  ( fix )
import           Optics

{- Given a binary tree, produce the sums of all
   the paths from the root to each of the leaves.

   NeoVim with HLS (Haskell Language Server)

   $> ghcid -W -a -c 'cabal repl lib:graph-mach-core'

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{-# LANGUAGE GADTs #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}

-- |
module Arithmetic.Expr where

import Data.Char (chr)
import GHC.Real (RealFrac (truncate))

smunix

# I found some good resources but they seem to do a bit too much (maybe from a time when there were more bugs).
# So here's a minimal Gist which worked for me as an install on a new M1 Pro.
# Inspired by https://github.com/malob/nixpkgs I highly recommend looking at malob's repo for a more thorough configuration
#
# Let's get started
#
# Let's install nix (at the time of writing this is version 2.5.1
curl -L https://nixos.org/nix/install | sh

# I might not have needed to, but I rebooted