Kristján Pétursson kristjan

Good extractions

Muddy

Wrong frame

I, Object!

This post is adapted from my answer to this Stack Overflow question. If you want to start from the beginning of the universe and build out, go read that one. If you prefer to start with something you can touch and work backwards, here we go.

Ruby likes ducks. Which is to say that when we're coding, and we have an object, we don't particularly care what kind of object it is, so long as it responds to the messages we send it. It might be a Duck or a Child or a

Disclaimer: None of this code was actually run!

What's a Promise

A way to handle something that happens asynchronously. Instead of getting your result back, you get a promise back that you can handle in a success way and a failure way. At some point in the future, the promise resolves to one of those cases, passing your success/failure functions the applicable data.

Why use promises?

Keybase proof

I hereby claim:

I am kristjan on github.
I am kristjan (https://keybase.io/kristjan) on keybase.
I have a public key whose fingerprint is 90B8 10A8 031E E111 893B 49B4 9455 B368 7480 A7AA

To claim this, I am signing this object:

	#!/usr/bin/env ruby

	# Automatically convert most of the syntax differences between Mocha and RSpec
	# Mocks.
	#
	# Does not handle:
	# - Multiline statements like `Foo\n.expects`
	# - `with` being given a block
	# - Probably other things
	#

	tags = %w[tag1 tag2 tag3]
	h = tags.product([[]]).to_h
	#=> {"tag1"=>[], "tag2"=>[], "tag3"=>[]}
	h['tag1'] << 1
	#=> [1]
	h
	#=> {"tag1"=>[1], "tag2"=>[1], "tag3"=>[1]}

	$ rails c
	Loading development environment (Rails 4.1.2)
	[1] pry(main)> Specialist.find(15)
	Specialist Load (0.9ms) SELECT "specialists".* FROM "specialists" WHERE "specialists"."id" = $1 LIMIT 1 [["id", 15]]
	=> #<Specialist id: 15, ...>
	[2] pry(main)> ActiveRecord::Base.logger.silence(Logger::FATAL) { Specialist.find(16) }
	=> #<Specialist id: 16, ...>

	# All colors on all applications
	$ for app in `heroku apps \| tail -n +2`; do heroku config --app $app \| cut -d':' -f1 \| grep HEROKU_POSTGRESQL \| cut -d_ -f3; done \| sort \| uniq -c \| sort -rn
	4 WHITE
	3 CHARCOAL
	2 YELLOW
	2 ORANGE
	2 ONYX
	2 CRIMSON
	2 COBALT
	2 BRONZE

	# $auth from auth.sh
	# $spreadsheet_id from get_spreadsheets.sh
	# $worksheet_id from get_worksheets.sh
	curl \
	--header "Authorization: GoogleLogin auth=$auth" \
	--header 'Content-Type: application/atom+xml' \
	-d @data.xml \
	-X POST \
	"https://spreadsheets.google.com/feeds/list/$spreadsheet_id/$worksheet_id/private/full"
	# Example data in data.xml

	module RequireImplementation
	def require_implementation(method_name)
	define_method method_name do
	raise NotImplementedError, "#{self.class.name} must implement #{method_name}"
	end
	end
	end


	class TestClass