Pawel Szulc EncodePanda

"Specifiing distributed systems with TLA+"

Elevator pitch:

Learn how to use TLA+ to study, design and specify your algorithms. This workshop is designed to teach you about TLA+ from the ground up. We will start with simple distributed algorithms and slowly move toward more complex ones. Knowledge you gain can be immediatly applied at work next day after the workshop

Description:

TLA+ is a formal specification language developed by Leslie Lamport, designed to specify, model, document, and verify concurrent systems. It empowers your ability to clearly specify your design choices in the form of a formal specification, but also (even more importantly) can formally verify that your design choice is correct—meaning that it is both safe (does not break any rules) and live (over time it converges toward the result).

Since macOS Catalina, the root drive is read-only. The solution is to create a separate APFS volume and a “synthetic” /nix directory which points to it:

# Check if /nix exists, if not:
echo 'nix' | sudo tee -a /etc/synthetic.conf
# this will create a "synthetic" empty directory /nix

# REBOOT so macOS sees the synthetic directory

# After rebooting, create an APFS volume for Nix

hi all, I'm trying to get my head around functional dependencies I've created a simplified version of MonadReader that has no functional dependencies

class MyMonadReader r m where
  ask :: m r

What works as expected

When creating instances like

	1 Formal specification applied (with TLA+)
	=========================================

	1.1 Elevator Pitch
	~~~~~~~~~~~~~~~~~~

	Formal verification promises software without bugs. At the same time
	even its name scares programmers away ("It's math! run for your
	lives!"). This talk will familiarize you with one form of formal
	verification: a model checker - one that is available in a formal

	rn_stop() {
	echo "stop all existing rnode processes"
	kill $(ps aux \| grep '[r]node' \| awk '{print $2}')
	}

	rn_clean() {
	echo "clean .rnode folders"
	echo ~/.rnode*
	rm -rf ~/.rnode*
	echo "create bootstrap rnode folder"

	{-# LANGUAGE KindSignatures #-}
	module Lib where

	data Console k =
	Done k \|
	PrintLine String (Console k) \|
	ReadLine (String -> Console k)

	instance Functor Console where
	fmap f (Done a) = Done (f a)

	{-# LANGUAGE DeriveAnyClass #-}
	{-# LANGUAGE DeriveGeneric #-}
	{-# LANGUAGE OverloadedStrings #-}
	module Main where

	import Control.Applicative
	import Control.Monad
	import Database.PostgreSQL.Simple
	import GHC.Generics (Generic)

	# stylish-haskell configuration file
	# ==================================

	# The stylish-haskell tool is mainly configured by specifying steps. These steps
	# are a list, so they have an order, and one specific step may appear more than
	# once (if needed). Each file is processed by these steps in the given order.
	steps:
	# Convert some ASCII sequences to their Unicode equivalents. This is disabled
	# by default.
	# - unicode_syntax:

	nix-shell --pure --show-trace
	building '/nix/store/dkmy7cp9dqb2xqnjx1x3lgarn5y2kv07-all-cabal-hashes-component-stylish-haskell-0.9.2.2.drv'...
	tar: */stylish-haskell/0.9.2.2/stylish-haskell.json: Not found in archive
	tar: */stylish-haskell/0.9.2.2/stylish-haskell.cabal: Not found in archive
	tar: Exiting with failure status due to previous errors
	builder for '/nix/store/dkmy7cp9dqb2xqnjx1x3lgarn5y2kv07-all-cabal-hashes-component-stylish-haskell-0.9.2.2.drv' failed with exit code 2
	cannot build derivation '/nix/store/d9281ziwi2rkfrk40w1y55krxym43p93-cabal2nix-stylish-haskell-0.9.2.2.drv': 1 dependencies couldn't be built
	error: while evaluating the attribute 'buildInputs' of the derivation 'ghc-shell-for-packages' at /nix/store/zrz1pihi0blg5mzchv19agqkjxd2vlag-nixos-release-19.03/pkgs/development/haskell-modules/make-package-set.nix:301:9:
	while evaluating 'getOutput' at /nix/store/zrz1pihi0blg5mzchv19agqkjxd2vlag-nixos-release-19.03/lib/attrsets.nix:464:23, called from undefined position:
	while evaluating anon

	Pawel Szulc


	Table of Contents
	_________________

	1 Install Nix
	2 Install Brew :(
	3 Zsh and Oh my zsh
	.. 3.1 Install zsh and zsh-completions