Mikael Konutgan kmikael

How I Wish Racket Was First Explained To Me

I've been taking a compilers class this semester from Matt Might, which has been a great experience. Amongst the most challenging/interesting aspects of the course has been taming Racket, a Scheme-y/LISP-y language (I'll leave it at that).

Having never used anything functional/LISP-y in my days, this was a brand new experience. On the whole, it was good, but here's how I wish my first introduction to the language had gone as it would have set me on the right foot. While I'm focusing on Racket here, I imagine this same thing applies to LISP/Scheme and its derivatives.

Code vs. Data

I read everywhere that, "In Racket, code and data are the same thing." That sentence alone was useless to me, and it took a number of weeks before I "got it." Perhaps this explanation may have been more helpful:

Generate the list yourself:

$ cd /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS*.sdk/System/Library/Frameworks/UIKit.framework/Headers
$ grep UI_APPEARANCE_SELECTOR ./*     | \
  sed 's/NS_AVAILABLE_IOS(.*)//g'     | \
  sed 's/NS_DEPRECATED_IOS(.*)//g'    | \
  sed 's/API_AVAILABLE(.*)//g'        | \
  sed 's/API_UNAVAILABLE(.*)//g'      | \
 sed 's/UI_APPEARANCE_SELECTOR//g' | \

Alfred Extensions to create new reminders or notes

OS X Mountain Lion ships with two new apps, Reminders and Notes, which are basically OS X counterparts of the standard iOS apps with the same names. One nice thing about these new apps is that they are scriptable.

This means that I was able to create two simple AppleScripts and thus an Alfred extensions to make a new reminder in the default list and to make a new note in the default folder.

You can view the sources of the AppleScripts below.

Examples

I'm a fan of MiniTest::Spec. It strikes a nice balance between the simplicity of TestUnit and the readable syntax of RSpec. When I first switched from RSpec to MiniTest::Spec, one thing I was worried I would miss was the ability to add matchers. (A note in terminology: "matchers" in MiniTest::Spec refer to something completely different than "matchers" in RSpec. I won't get into it, but from now on, let's use the proper term: "expectations").

Understanding MiniTest::Expectations

Let's take a look in the code (I'm specifically referring to the gem, not the standard library that's built into Ruby 1.9):

# minitest/spec.rb

module MiniTest::Expectations

	platform :ios, '5.0'

	# Awesome networking
	pod 'AFNetworking'

	# Backported UICollectionView
	pod 'PSTCollectionView'

	# Rich text
	pod 'TTTAttributedLabel'

	Sequel.migration do
	up do
	run 'CREATE EXTENSION "uuid-ossp"'

	create_table :products do
	column :id, :uuid, :default => Sequel.function(:uuid_generate_v4), :primary_key => true
	end
	end
	end

	// Created by Nick Snyder on 11/13/12.
	// https://gist.github.com/nicksnyder/4075682
	// http://stackoverflow.com/questions/12927027/uicollectionview-flowlayout-not-wrapping-cells-correctly-ios
	// NDCollectionViewFlowLayout.h
	@interface NDCollectionViewFlowLayout : UICollectionViewFlowLayout

	@end

	$stack, $draws = [], {}

	def method_missing *args
	return if args[0][/^to_/]
	$stack << args.map { \|a\| a or $stack.pop }
	$draws[$stack.pop(2)[0][0]] = args[1] if args[0] == :<
	end

	class Array
	def +@

	require './interface'
	puts to_strings(->(limit) {
	->(lst) {
	->(f) {
	->(f) {
	->(g) {
	->(n) {
	f.(g.(g)).(n)
	}
	}.(->(g) {

	#!/usr/bin/env ruby
	# Uses the Readability Metrics API from http://ipeirotis.appspot.com/readability-api.html
	# Accepts text from STDIN (piped) or as an argument
	=begin examples
	pbpaste\|text_score.rb # copy text and run (on OS X) to get the stats for the clipboard.
	cat myfile.md\|text_score.rb # get scores for the contents of a file
	=end

	require 'open-uri'
	require 'net/http'