That's Not Very Ruby of You

That’s Not Very Ruby of You @erniemiller http://erniemiller.org

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What is Ruby?

#include <stdio.h> ! int main() { int a = -1;
int b = -1; int c = -1; ! while (a != 0 || b != 0) { printf("Enter two numbers (0 0 to quit): "); scanf("%d%d", &a, &b); ! c = a + b; ! printf("The sum of the numbers you entered is %d\n", c); } }

def int(*) end ! def main yield end ! int
main() { int a = -1; int b = -1; int c = -1; ! while (a != 0 || b != 0) printf("Enter two numbers (0 0 to quit): "); a, b = scanf("%d%d"); ! c = a + b; ! printf("The sum of the numbers you entered is %d\n", c); end }

require 'scanf' ! def int(*) end ! def main yield
end ! int main() { int a = -1; int b = -1; int c = -1; ! while (a != 0 || b != 0) printf("Enter two numbers (0 0 to quit): "); a, b = scanf("%d%d"); ! c = a + b; ! printf("The sum of the numbers you entered is %d\n", c); end } Enter two numbers (0 0 to quit): 2 4 The sum of the numbers you entered is 6 Enter two numbers (0 0 to quit): 1 2 The sum of the numbers you entered is 3 Enter two numbers (0 0 to quit): 0 0 The sum of the numbers you entered is 0

<? $fruits = array('banana', 'apple', 'orange') ?> A sorted list
of fruits: ! <? sort($fruits) ?> <? foreach ($fruits as $fruit) { ?> * <?= $fruit ?> ! <? } ?> ! <?= $fruits[0] ?> is spelled: <?= implode(' ', str_split($fruits[0])) ?> <? $rubies = array( '1.8' => 'unsupported', '1.9' => 'supported', '2.0' => 'supported' ) ?> ! ! Important note regarding Ruby versions: ! <? foreach ($rubies as $ruby => $status) { ?> * <?= implode(' is ', array($ruby, $status)) ?> ! <? } ?>

PersonalHomePage.new.render(DATA.read) ! __END__ <% $fruits = array('banana', 'apple', 'orange') %>
A sorted list of fruits: ! <% sort($fruits) %> <% for $fruit in $fruits %> * <%= $fruit %> <% end %> ! <%= $fruits[0] %> is spelled: <%= implode(' ', str_split($fruits[0])) %> <% $rubies = array( '1.8' => 'unsupported', '1.9' => 'supported', '2.0' => 'supported' ) %> Important note regarding Ruby versions: ! <% for ($ruby, $status) in $rubies %> * <%= implode(' is ', array($ruby, $status)) %> <% end %>

require 'erb' ! class PersonalHomePage def array(*args) Hash === args.first
? args.first : Array(args) end ! def implode(*args) array_join(*args.reverse) end ! Array.instance_methods.each do |method_name| define_method "array_#{method_name}", ->(array, *args, &block) { array.to_a.send(method_name, *args, &block) } end ! String.instance_methods.each do |method_name| define_method "str_#{method_name}", ->(string, *args, &block) { string.send(method_name, *args, &block) } end ! alias sort array_sort! ! def str_split(string, length = 1) string.scan(/.{1,#{length}}/) end ! def render(template) ERB.new(template, nil, '<>').run(binding) end end ! PersonalHomePage.new.render(DATA.read)

A sorted list of fruits: ! * apple * banana
* orange ! apple is spelled: a p p l e ! Important note regarding Ruby versions: ! * 1.8 is unsupported * 1.9 is supported * 2.0 is supported

App = { say: function(string) { console.log(string) }, ifMultipleOf: function(number,
check, callback) { (check % number) == 0 ? callback(check) : nil; }, ifEven: function(number, callback) { App.ifMultipleOf(2, number, callback); }, proclaimEvenness: function(number) { App.say("It would appear that "+number+" is an even number."); } } App.say("Hello, world!"); App.ifEven(42, App['proclaimEvenness']);

! ! ! ! ! ! ! App = {
say: ->(string) { console.log(string) }, ifMultipleOf: ->(number, check, callback) { (check % number) == 0 ? callback.(check) : nil; }, ifEven: ->(number, callback) { App.ifMultipleOf(2, number, callback); }, proclaimEvenness: ->(number) { App.say("It would appear that "+number+" is an even number."); } } App.say("Hello, world!"); App.ifEven(42, App['proclaimEvenness']);

class Hash def method_missing(method_id, *args, &block) has_key?(method_id) ? self[method_id].(*args, &block)
: super end ! def [](key) fetch(key) { fetch(key.to_sym) } # LOL GC end ! def respond_to_missing?(method_id, include_private = false) has_key?(method_id) || super end end ! class Fixnum alias to_str to_s end ! class Console def log(*args) puts *args end end ! console = Console.new ! Hello, world! It would appear that 42 is an even number.

class Person: def __init__(self, name, age): self.name = name self.age
= age ! person = Person('Ernie', 36) ! print person.name print person.age person.nonexistent_attribute = 'Seriously?' print person.nonexistent_attribute

! ! ! ! class Person def __init__(se1f, name, age)
se1f.name = name se1f.age = age end end ! person = Person('Ernie', 36) ! print person.name print person.age person.nonexistent_attribute = 'Seriously?' print person.nonexistent_attribute

class Object alias print puts ! def setter_block(name) ->(*args) {
instance_variable_get(:@__attributes__)[name] = *args } end ! def getter_block(name) ->(*args) { instance_variable_get(:@__attributes__)[name] } end ! def method_missing(method_id, *args, &block) method_name = method_id.to_s if method_name.end_with?('=') && self.instance_variable_defined?(:@__attributes__) attribute_name = method_name.chop define_singleton_method(method_name, setter_block(attribute_name)) define_singleton_method(attribute_name, getter_block(attribute_name)) send(method_name, *args, &block) elsif Object.const_defined?(method_id) obj = Object.const_get(method_id).allocate obj.instance_variable_set(:@__attributes__, {}) obj.__init__(obj, *args, &block) obj else super end rescue NameError => e super end end Ernie 36 Seriously?

WxxÑ g{Éâz{àá If your code has a syntax error, does
it stop being Ruby?

Interpreter

People

Happiness

Ruby is a language

Ruby is a storytelling tool

We Are Storytellers

def edit_distance length1, length2 = @string1.length, @string2.length # puts "length1:
#{length1} length2: #{length2}" # row = [nil] * length1 # prev_row = row prev_row = row = (0..length1).to_a (1..length2).each do |y| # puts "prev_row: #{prev_row.inspect}" row = [y] * (length1 + 1) # (1..length1).each do |column| (1..length1).each do |x| # if @string1[x - 1] == @string2[y - 1] # row[column] = prev_row[column - 1] # else row[x] = if @string1[x - 1] == @string2[y - 1] prev_row[x - 1] else # row[column] = find_min(row, prev_row, column) [ row[x - 1] + 1, # delete? prev_row[x] + 1, # insert? prev_row[x - 1] + 1 # substitute? ].min end end # puts "row: #{row.inspect}" prev_row = row end row.last end

class City def initialize @traits = [] end ! def
trait description @traits << description end ! def space needle "for knitting space socks." end ! def grunge music "smells like teen spirit" end ! def emerald city, usa trait space :needle trait grunge :music end end

Before we proceed…

class Greeter def initialize ( greeting ) @greeting = greeting
end def greet ( name, number_of_greetings = 1 ) number_of_greetings.times do puts ("#{ @greeting }, #{ name }!") end end end

class Greeter ! def initialize(greeting) @greeting = greeting end !
def greet(name, number_of_greetings = 1) number_of_greetings.times do puts "#{@greeting}, #{name}!" end end ! end

Soft tabs. Two spaces. Vertical space is free! All day,
every day.

class Greeter ! # Initialize with a greeting, x. def
initialize(x) @x = x end ! # Greet the person/group named x, # i times. def greet(x, i = 1) i.times { puts "#{@x}, #{x}!" } end ! end

If it’s not self-explanatory, it’s deﬁnitely not “X”. Unless you’re
modeling a treasure map, or tic-tac-toe.

class Greeter ! def initialize(the_greeting_or_prefix) @the_greeting_or_prefix = the_greeting_or_prefix end !
def greet(name_of_person_to_greet, number_of_times_to_greet = 1) number_of_times_to_greet.times do puts “#{@the_greeting_or_prefix}, #{name_of_person_to_greet}!” end end ! end

You are very original. And you should be very proud
of yourself.

class AwesomeGreeter ! def initialize(theSalutation) @theSalutation = theSalutation end !
def greetPersonOrGroup(nameOfGreetable, numberOfTimesToGreet = 1) numberOfTimesToGreet.times do puts("#{@theSalutation}, #{nameOfGreetable}!") end end ! end

Ruby is not Java. This is what we call in
the industry a “feature.” Also: http://tinyurl.com/camelCase

class Word ! def similarity_to(other_word) score = normalized_distance(self, other_word) score
+= 100 if synonyms.include?(other_word) return score end ! end

class Word ! def similarity_to(other_word) score = normalized_distance(self, other_word) score
+= 100 if synonyms.include?(other_word) score end ! end

class Word ! def similarity_to(other_word) return 100 if synonyms.include?(other_word) normalized_distance(self,
other_word) end ! end

return Everything is backward. It’ll be okay.

class Iffy ! def iffy if thing_is_true? do_some_stuff if other_thing_is_true?
do_some_more_stuff if truthiness_is_everywhere do_the_stuffiest_stuff_ever unless just_kidding? end else do_some_different_stuff end else do_a_fallback_thing end end ! end

YOU CAN NOT HAS BUCKET OF LOGIC

80-column lines An early warning system for complexity.

module Util module_function ! def dashify(string) string.scan(/./).join('-') end ! def
array_of_strings?(o) o.is_a?(Array) && o.all? { |obj| obj.is_a?(String) } end ! def array_of_arrays?(o) o.is_a?(Array) && o.all? { |obj| obj.is_a?(Array) } end ! def array_of_dates?(o) o.is_a?(Array) && o.all? { |obj| obj.respond_to?(:to_time) } end ! end

YOU CAN NOT HAS BUCKET OF METHODS

YOU CAN NOT HAS BUCKET OF METHODS if Class <
Module puts 'That goes for you too, Class.' end

def initialize(attributes = {}) @attributes = attributes end

def initialize(attributes = {}) @attributes = typecast(attributes) end

YOU CAN NOT HAS BUCKET OF DATA

def initialize(attributes = {}) @attributes = Attributes.new(attributes) end

class InstallationsController < ActionController::Base ! def schedule desired_date = params[:desired_date]
if request.xhr? begin if @installation.pending_credit_check? render :json => {:errors => ["Cannot schedule installation while credit check is pending"]}, :status => 400 return end audit_trail_for(current_user) do if @installation.schedule!(desired_date, :installation_type => params[:installation_type], :city => @city) if @installation.scheduled_date date = @installation.scheduled_date.in_time_zone(@installation.city.timezone).to_date render :json => {:errors => nil, :html => schedule_response(@installation, date)} end else render :json => {:errors => [%Q{Could not update installation. #{@installation.errors.full_messages.join(' ')}}] } end end rescue ActiveRecord::RecordInvalid => e render :json => {:errors => [e.message] } rescue ArgumentError => e render :json => {:errors => ["Could not schedule installation. Start by making sure the desired date is on a business day."]} end else if @installation.pending_credit_check? flash[:error] = "Cannot schedule installation while credit check is pending" redirect_to installations_path(:city_id => @installation.city_id, :view => "calendar") and return end begin audit_trail_for(current_user) do if @installation.schedule!(desired_date, :installation_type => params[:installation_type], :city => @city) if @installation.scheduled_date if @installation.customer_provided_equipment? flash[:success] = %Q{Installation scheduled} else flash[:success] = %Q{Installation scheduled! Don't forget to order the equipment also.} end end else flash[:error] = %Q{Could not schedule installation, check the phase of the moon} end end rescue => e flash[:error] = e.message end redirect_to(@installation.customer_provided_equipment? ? customer_provided_installations_path : installations_path(:city_id => @installation.city_id, :view => "calendar")) end end ! end

class InstallationsController < ActionController::Base ! def schedule ScheduleInstallation.new(schedule_responder).call end !
private ! def schedule_responder if request.xhr? AJAXResponder.new(self) else HTMLResponder.new(self) end end ! end

ETOOMANYOBJECTS

-Oriented Object Programming

-Oriented Awesome Programming

escriptive D

escriptive Pr

Naming Things

We Are Storytellers

Name your characters.

Name their! actions.

Asha Yara

“ Vigorous writing is concise

“ Vigorous writing is concise.

“ A sentence should contain no unnecessary words, a paragraph
no unnecessary sentences,

“ for the same reason that a drawing should have
no unnecessary lines and a machine no unnecessary parts.

“ This requires not that the writer make all sentences
short or avoid all detail and treat subjects only in outline, but that every word tell.

HAPPINESS Expressiveness! + Power

WITH GREAT POWER COMES

WITH GREAT POWER COMES GREAT RESPONSIBILITY

= Expressiveness English

Expressiveness ≠ English

array = %w(first second third fourth fifth) ! array.first #
=> "first" array.last # => "fifth"

class Array ! def second self[1] end ! def third
self[2] end ! def fourth self[3] end ! def fifth self[4] end ! def forty_two self[41] end ! end

self[2] end ! def fourth self[3] end ! def fifth self[4] end ! def forty_two self[41] end ! end array = %w(first second third fourth fifth) ! array.second # => "second" array.fourth # => "fourth"

self[2] end ! def fourth self[3] end ! def fifth self[4] end ! def forty_two self[41] end ! end array = %w(first second third fourth fifth) ! array.second # => "second" array.fourth # => "fourth" class Array ! def penultimate # EXPRESSIVE self[-2] end ! def antepenultimate # ZOMG SO EXPRESSIVE self[-3] end ! end

self[2] end ! def fourth self[3] end ! def fifth self[4] end ! def forty_two self[41] end ! end array = %w(first second third fourth fifth) ! array.second # => "second" array.fourth # => "fourth" class Array ! def penultimate # EXPRESSIVE self[-2] end ! def antepenultimate # ZOMG SO EXPRESSIVE self[-3] end ! end array.penultimate # => "fourth" array.antepenultimate # => "third"

array = %w(first second third fourth fifth) ! array.include?('second') #
=> true

class Object ! def in?(container) container.include? self end ! end

class Object ! def in?(container) container.include? self end ! end
array = %w(first second third fourth fifth) ! 'second'.in? array # => true

Before you monkey patch…

Does it address a real problem? * not a monkey

Does it follow OO! principles? * still not a monkey

Metaprogramming: It makes boring problems interesting.™ Class Macros

attr_reader :name, :age attr_writer :height, :weight attr_accessor :motto, :favorite_food

has_many :posts, :inverse_of => :user

has_many :posts, -> { order(:created_at => :desc) }, :inverse_of =>
:user, :class_name => 'Article', :foreign_key => 'person_id', :validate => false, :autosave => true, :dependent => :destroy do def method_in_an_anonymous_module_because_we_certainly_wont_regret_this puts 'LOL LSP!' end end

class Cat delegate :work, :to => :owner, :prefix => 'servant',
:allow_nil => true end

def delegate(*methods) options = methods.pop unless options.is_a?(Hash) && to =
options[:to] raise ArgumentError, 'Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, to: :greeter).' end ! prefix, allow_nil = options.values_at(:prefix, :allow_nil) ! if prefix == true && to =~ /^[^a-z_]/ raise ArgumentError, 'Can only automatically set the delegation prefix when delegating to a method.' end ! method_prefix = \ if prefix "#{prefix == true ? to : prefix}_" else '' end ! file, line = caller.first.split(':', 2) line = line.to_i ! to = to.to_s to = 'self.class' if to == 'class' ! methods.each do |method| definition = (method =~ /[^\]]=$/) ? 'arg' : '*args, &block' ! if allow_nil module_eval(<<-EOS, file, line - 3) def #{method_prefix}#{method}(#{definition}) _ = #{to} if !_.nil? || nil.respond_to?(:#{method}) _.#{method}(#{definition}) end end EOS else exception = %(raise "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}") ! module_eval(<<-EOS, file, line - 2) def #{method_prefix}#{method}(#{definition}) _ = #{to} _.#{method}(#{definition}) rescue NoMethodError if _.nil? #{exception} else raise end end EOS end end end

class Module private ! def delegate(*args) dest, prefix = _extract_valid_delegation_options(args.pop)
_define_delegators(caller_locations.first, prefix, dest, args) end ! def delegate_maybe(*args) dest, prefix = _extract_valid_delegation_options(args.pop) _define_delegators( caller_locations.first, prefix, "(_ = #{dest}; _.nil? ? NilDelegate.new : _)", args ) end ! def _define_delegators(from, prefix, accessor, args) args.each do |arg| method_name = [prefix, arg].compact.join('_') module_eval( _delegator(accessor, arg, method_name), from.path, from.lineno - 2 ) end end ! def _delegator(accessor, destination_method, local_method) %{ def #{local_method}(*args, &block) #{accessor}.__send__(:#{destination_method}, *args, &block) end } end ! def _extract_valid_delegation_options(opts) if Hash === opts && opts.has_key?(:to) [opts[:to].to_s.sub(/^([a-z])/, 'self.\1'), opts[:prefix]] else raise ArgumentError, 'Invalid delegation options. Delegate with :to.' end end end

class NilDelegate < BasicObject delegate *(nil.methods - [:__send__, :object_id]), :to
=> :__nil__ ! private ! def __nil__ nil end ! def method_missing(method_id, *args, &block) nil end ! def respond_to_missing?(method_id, include_private = false) true end end

# No options needed! YAY SIMPLICITY! has_some_awesome_feature

extend MyAwesomeFeature include MyAwesomeFeature

EVERYBODY LOVES RULES!

What, not how 1

Idempotent 2

Order! Independent 3

Straightforward 4

Free of! Branching 5

Rules for Class Macros What, not how! Idempotent! Order independent!
Straightforward! Free of branching 1 2 3 4 5

You have to know the rules in order to break
them. Otherwise, it’s no fun.

Happiness

Surprises

Callbacks You didn’t really think I would leave these out?

class Base

require 'active_support/callbacks' ! class Base ! include ActiveSupport::Callbacks ! define_callbacks
:auto_arming ! set_callback :auto_arming, :before do @weapons_armed = true end ! def fire_lasers run_callbacks :auto_arming do puts 'PEW PEW PEW!' if @weapons_armed end end ! end ! base = Base.new base.fire_lasers # => PEW PEW PEW!

What, not how! Idempotent! Order independent! Straightforward! Free of branching
1 2 3 4 5 Rules Callbacks Not consistently. No. Nope. LOL!! Honorary tree.

class Base ! include ActiveSupport::Callbacks ! define_callbacks :auto_arming ! set_callback
:auto_arming, :before, :arm_weapons, :if => :not_armed?, :unless => :training_mode? ! # ... ! def fire_lasers run_callbacks :auto_arming do puts 'PEW PEW PEW!' if @weapons_armed end end ! end

class SecretBase < Base ! # This base shouldn't go
making loud PEW PEW PEW noises # unless it really, really needs to. skip_callback :auto_arming, :before, :arm_weapons, :unless => :under_attack? ! # ... ! end

include! extend! prepend

Your characters can have of one another. DEMANDS and EXPECTATIONS

module AutoArming ! def fire_lasers @weapons_armed = true super end
! end ! class Base ! def fire_lasers puts 'PEW PEW PEW!' if @weapons_armed end ! end ! base = Base.new base.extend AutoArming base.fire_lasers # => PEW PEW PEW!

module AutoArming ! def fire_lasers @weapons_armed = true super end
! end ! class Base ! prepend AutoArming ! def fire_lasers puts 'PEW PEW PEW!' if @weapons_armed end ! end ! base = Base.new base.fire_lasers # => PEW PEW PEW!

module AutoArming ! def fire_lasers @weapons_armed = true if should_autoarm?
super end ! def should_autoarm? true end ! end class SecretBase < Base ! def should_autoarm? under_attack? end ! # ... ! end class Base ! prepend AutoArming ! def fire_lasers puts 'PEW PEW PEW!' if @weapons_armed end ! end

1 2 3 4 5 Rules extend/prepend

1 2 3 4 5 Rules extend/prepend Yes!

1 2 3 4 5 Rules extend/prepend Yes! Yep!

1 2 3 4 5 Rules extend/prepend Yes! It depends. Yep!

1 2 3 4 5 Rules extend/prepend Yes! It depends. Yep! Eeeeyup!

1 2 3 4 5 Rules extend/prepend Yes! It depends. Yep! Eeeeyup! Free as the wind (through a branchless tree)

base.singleton_class.ancestors # => [AutoArming, Base, Object, Kernel, BasicObject] base.is_a?(AutoArming) #
=> true base._fire_lasers_callbacks # => [#<ActiveSupport::Callbacks::Callback:0x007...>] Callbacks: extend/prepend:

This is Ruby. I KNOW THIS!

Reduce Cognitive Load and win at being lazy.

We Are Storytellers

MAKE  EVERY  WORD! TELL

MAKE  EVERY  WORD! TELL❤️

That's Not Very Ruby of You

That's Not Very Ruby of You

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