avnik

with (import <nixpkgs> {}).pkgs;
with import <nixpkgs/pkgs/development/haskell-modules/lib.nix> { inherit pkgs; };
let
  QuickCheck = haskellPackages.QuickCheck_2_9_2;
  quickcheck-io = haskellPackages.quickcheck-io.override { inherit QuickCheck; };
  quickcheck-instances = haskellPackages.quickcheck-instances.override { inherit QuickCheck; };
  hspec-meta = haskellPackages.hspec-meta.override { inherit QuickCheck quickcheck-io;};
  hspec-core = haskellPackages.hspec-core.override { inherit QuickCheck quickcheck-io hspec-meta;};
  hspec = haskellPackages.hspec.override { inherit QuickCheck hspec-core hspec-meta; };
  http-api-data = (doJailbreak haskellPackages.http-api-data_0_3_1).override {inherit QuickCheck hspec quickcheck-instances; };

expipiplus1

Multi user nix installation

Each section should be run as the user or as root, pay attention to which one!

Install nix single user

As $USER

curl https://nixos.org/nix/install | sh

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

michaelt

{-# LANGUAGE OverloadedStrings, BangPatterns #-}
module Main (main) where

import Criterion.Main

import Control.Applicative
import Data.Attoparsec.ByteString as P
import Data.Attoparsec.ByteString.Char8 (char8, endOfLine, isDigit_w8)
import Data.ByteString (ByteString)
import Data.Word (Word8)

fritzy

CREATE OR REPLACE FUNCTION table_update_notify() RETURNS trigger AS $$
DECLARE
  id bigint;
BEGIN
  IF TG_OP = 'INSERT' OR TG_OP = 'UPDATE' THEN
    id = NEW.id;
  ELSE
    id = OLD.id;
  END IF;
  PERFORM pg_notify('table_update', json_build_object('table', TG_TABLE_NAME, 'id', id, 'type', TG_OP)::text);

ocharles

> import Control.Monad.Trans
> import Control.Monad.Trans.Iter

The completely iterative free monad transformer lets us capture non-termination as an effect. Furthermore, it's a monad *transformer*, so we can add non-termination on top of other effects.

A convenient combinator is

> untilSuccess :: Monad m => m (Maybe a) -> IterT m a
> untilSuccess f = maybe (delay (untilSuccess f)) return =<< lift f

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

dmalikov

Various blog posts related to Nix and NixOS

---

General

• https://nixos.org/wiki/Main_Page Nix wiki. Awesome resource containing huge amount of manuals and documentation with examples.
• http://aflatter.de/nixos/ Alexander Flatter - NixOS. Installing NixOS inside a VirtualBox with a real-world configuration.nix example.
• http://lethalman.blogspot.it/search/label/nixpills Luca Bruno - Nix Pills. Series of posts describing how to install nix into some environment and how to use it.
• http://looprecur.com/blog/from-ubuntu-to-nixos/ Tim Sears - From Ubuntu to NixOS. Talk about experience migrating from Ubuntu to NixOS.