Denis dmokreckiy

A Primer on Ruby Method Lookup

Method lookup is a simple affair in most languages without multiple inheritance. You start from the receiver and move up the ancestors chain until you locate the method. Because Ruby allows you to mix in modules and extend singleton classes at runtime, this is an entirely different affair.

I will not build contrived code to exemplify the more complicated aspects of Ruby method lookup, as this will only serve to confuse the matter. If you are having trouble following method lookup in your own programs, it is not because Ruby has strange rules (it does), it is because your code is too tangled.

When you pass a message to an object, here is how Ruby finds what method to call:

1. Look within singleton class

TL;DR - Lambda means "function used as data".

Anonymous function means "function without a name".

This is one of the relatively few cases where the Wikipedia definition of a word, while not entirely wrong, is misleading. Lambdas and anonymous functions are distinct ideas.

These ideas are commonly confused because in many programming languages (and lambda calculus) all lambdas are anonymous or vise verse.

In JavaScript, not all lambdas are anonymous, and not all anonymous functions are lambdas, so the distinction has some practical meaning.

	#!/bin/sh

	versionMaj="1"
	versionMin="0"
	versionRev="1"
	version="$versionMaj.$versionMin-$versionRev"

	echo "Removing old Postman tarballs"
	rm -f $(ls Postman*.tar.gz)

	# Credit Brandon Weiss of http://anti-pattern.com/dirty-associations-with-activerecord

	# app/models/dirty_associations.rb
	module DirtyAssociations
	attr_accessor :dirty
	attr_accessor :_record_changes

	def make_dirty(record)
	self.dirty = true
	self._record_changes = record

	namespace :ts do
	desc "Run Thinking Sphinx in the foreground (for something like foreman)"
	task :run_in_foreground => ['ts:stop', 'ts:index'] do
	config = ThinkingSphinx::Configuration.instance
	controller = config.controller

	unless pid = fork
	exec "#{controller.bin_path}#{controller.searchd_binary_name} --pidfile --config #{config.configuration_file} --nodetach"
	end

	# Nginx+Unicorn best-practices congifuration guide. Heartbleed fixed.
	# We use latest stable nginx with fresh openssl, zlib and pcre dependencies.
	# Some extra handy modules to use: --with-http_stub_status_module --with-http_gzip_static_module
	#
	# Deployment structure
	#
	# SERVER:
	# /etc/init.d/nginx (1. nginx)
	# /home/app/public_html/app_production/current (Capistrano directory)
	#