Kiryl KL-7

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

Install Styler for Chrome https://chrome.google.com/webstore/detail/styler/bogdgcfoocbajfkjjolkmcdcnnellpkb?hl=en

Go to a review, click on the Styler "S" logo on the top right menu bar. Add the following CSS

span.k { color: #b05179 }
span.nc { color: #41618d }
span.kt { color: #41618d }

span.kc { color: #806DA2 ; font-weight: normal; }

Unmuting Twitch VODs

As you know, Twitch has made a weird decision to mute VODs if it finds copyrighted content in videos.

Here's how to enjoy VODs without this annoying mute feature.

Install Fiddler (tested on 4.4.9.2 on Windows).
Enable HTTPS decryption. If you are using Firefox, you will need to do this.
Rules -> Customize Rules...
Paste the following code in the OnBeforeResponse method:

Description

This simple script will take a picture of a whiteboard and use parts of the ImageMagick library with sane defaults to clean it up tremendously.

The script is here:

#!/bin/bash
convert "$1" -morphology Convolve DoG:15,100,0 -negate -normalize -blur 0x1 -channel RBG -level 60%,91%,0.1 "$2"

Results

Ruby 2.0 backwards incompatible changes

From Peter Cooper's Walkthrough:

lines, bytes, chars, codepoints returned an Enumerator in 1.9 -> use each_lines, each_bytes, each_chars, each_codepoints instead for an Enumerator
# encoding: utf-8 is the default (which impacts regular expressions that expect it to be us-ascii, eg. vpim)
respond_to? on a protected method returns false (was true)
inspect doesn't use the redefined to_s
Array#values_at returns nil for each number outside of the array
CSV.dump & CSV.load are gone (object serialization)

	// paste in your console
	speechSynthesis.onvoiceschanged = function() {
	var msg = new SpeechSynthesisUtterance();
	msg.voice = this.getVoices().filter(v => v.name == 'Cellos')[0];
	msg.text = Object.keys(window).join(' ');
	this.speak(msg);
	};

	brew install homebrew/dupes/apple-gcc42
	rbenv install 1.9.3-p484
	rbenv global 1.9.3-p484
	git clone https://github.com/cowboyd/libv8.git
	cd libv8
	git checkout 3.11
	export CC=/usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/gcc-4.2
	export CXX=/usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/g++-4.2
	export CPP=/usr/local/Cellar/apple-gcc42/4.2.1-5666.3/bin/cpp-4.2
	bundle install

	class GrapeRequestLogSubscriber < ActiveSupport::LogSubscriber

	def grape_controller(event)
	request = Rack::Request.new(event.payload).env
	response = Rack::Response.new(event.payload)
	data = extract_request(request)
	data.merge! extract_status(response)
	logger.send(:warning, data.to_json)
	end

	# Borrowed from https://github.com/y310/rspec-retry/blob/master/lib/rspec/retry.rb

	CAPYBARA_TIMEOUT_RETRIES = 3

	RSpec.configure do \|config\|
	config.around(:each, type: :feature) do \|ex\|
	example = RSpec.current_example
	CAPYBARA_TIMEOUT_RETRIES.times do \|i\|
	example.instance_variable_set('@exception', nil)
	self.instance_variable_set('@__memoized', nil) # clear let variables

	[mysqld]

	init_connect='SET collation_connection = utf8mb4_unicode_ci'
	init_connect='SET NAMES utf8mb4'
	character-set-server = utf8mb4
	character-set-client = utf8mb4
	collation-server = utf8mb4_unicode_ci
	skip-character-set-client-handshake

	innodb_file_format = Barracuda