Sugar-Free Ruby - Speaker Deck

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Sugar-Free Ruby A Look at Object-First Teaching

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Who is this guy? Steven! Ragnarök contact = { "GitHub" => "nuclearsandwich", "Freenode" => "nuclearsandwich", "Email" => "steven@nuclearsandwich.com", "WWW" => "www.nuclearsandwich.com", "Twitter" => "@nuclearsandwich" } ''That guy with all the opinions''

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Teaching Programming

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Why is teaching so damn hard?

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Why is teaching so damn hard? • It's hard to remember learning to program

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Why is teaching so damn hard? • It's hard to remember learning to program • It's hard to share knowledge instead of guard it

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Why is teaching so damn hard? In short: it takes a lot of self reﬂection to teach well.

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Teaching Programming It's getting better

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Kids learn: • Game Builder • Scratch • Python • Hackety-Hack / Shoes

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Programming is fun

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• Workshops for Women • Kids Ruby • Workshops / Curriculum in other languages

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Programming is hard… But only this hard

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RailsBridge: Workshops for Women • Install all the things the night before • One full day • Focus on Ruby, Rails, or split based on experience

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Teaching Ruby The challenge

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Why do you want to learn Ruby?

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Why do you want to learn Ruby? • I hate my job and hear programmers make bank

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Why do you want to learn Ruby? • I hate my job and hear programmers make bank • I know how to program but not Ruby

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Why do you want to learn Ruby? • I hate my job and hear programmers make bank • I know how to program but not Ruby • I'm curious about programming

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Disclaimer This point onward: Open minds only

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Disclaimer Haters, the doors are stage left

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Teaching Ruby The (Good?) Old Fashioned Way

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Numbers 5 + 5 #=> 10 9 / 2 #=> 4 9.0 / 2 #=> 4.5

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Strings and Symbols 'Hello' #=> "Hello" :what? #=> :what? "Hello, " + "World!" #=> "Hello, World!"

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Boolean Values true #=> true false #=> false 20 < 100 #=> true true and false #=> false true or false #=> true

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Arrays and Hashes [ 1, 2, 3.0, "four" ] { :name => "Steven!", :age => 24, :species => "human" }

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Variable Assignment my_name = "Steven!" my_age = 24

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Variable Access # ten years from now my_age + 10 #=> 34 # I hashify myself { :name => my_name, :age => my_age } #=> {:name => "Steven!", # :age => 24}

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Console Output puts my_name Steven! #=> nil puts my_age + 10 34 #=> nil

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Conditionals if my_name == "Steven!" puts "Hello!" else puts "Who are you?" end Hello! #=> nil

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Loops while my_age < 30 do puts "Enjoying my twenties" my_age = my_age + 1 end

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Methods "foo".upcase #=> "FOO"

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Teaching Ruby What's wrong with this picture?

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What's wrong with this picture? Six whole concepts come before methods.

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What's wrong with this picture? No mention whatsoever of classes.

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What's wrong with this picture? Why do we cling to this?

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Ruby is not a computer language.

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Ruby is not a computer language. So why are we teaching it like one?

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Teaching Objects Ruby is the computer

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But Steven!, If we try to teach all of that and Objects, their heads will explode!

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Everything is an Object 5 #=> 5 42.0 #=> 42.0 "Hello!" #=> "Hello!" [1, 2, 3] #=> [1, 2, 3]

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They Receive Messages "six".send :upcase #=> "SIX" 5.send :+, 9 #=> 14 17.send :nil? #=> false

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Objects Have (a) Class 5.send :class #=> Fixnum 4.0.send :class #=> Float ["he's", "crazy?"].send :class #=> Array

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Teaching Objects The pen and the scribe

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Instantiation pen = Object.new #=> #

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Method Deﬁnition def pen.to_s "A trusty pen" end #=> nil

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Message Sending pen.send :to_s #=> A trusty pen

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A Pinch of Sugar def pen.to_s "A trusty pen" end pen.to_s #=> A trusty pen

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Errors Are Your Friends pen.write "Hi there" #=> NoMethodError: undefined # method `write' for # A trusty pen:Object

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Use the Kernel, Luke def pen.write thing Kernel.puts thing end #=> nil

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Write Anything! pen.write "Hi" Hi #=> nil pen.write pen A trusty pen #=> nil

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Feature Request: Color pen.ink_color = "Blue" #=> NoMethodError: undefined # method `ink_color=' for # A trusty pen:Object def pen.ink_color= color @ink_color = color end #=> nil

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Showing Our Colors def pen.to_s "A trusty #{@ink_color} pen" end pen.ink_color = "purple" #=> "purple" pen #=> "A trusty purple pen"

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Implicit Receivers def pen.sparkly_write thing write "*;. #{thing} *;.*" end pen.sparkly_write pen *;. A trusty purple pen *;.*

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Conditionals Revisited def pen.html_write thing write if @ink_color "

#{thing}

" else "

#{thing}

" end end

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Teaching Ruby What have we introduced?

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Time to get classy… Scribe = Class.new do def initialize pen @pen = pen @items = Array.new end def note item @items.<< item end # to be continued

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…you blockhead # in the Scribe class body def write_everything @items.each do |item| @pen.write item end end end #=> Scribe

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Hiring a new scribe mielot = Scribe.new pen #=> # mielot.note "Time: #{Time.now}" mielot.note "This demo is over" mielot.write_everything Time: 2012-09-14 11:43:05 -0700 This demo is over

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Teaching Ruby with Objects

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Teaching Objects with Ruby

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Why is this better? The object metaphor provides a context for everything else we learn about Ruby

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Why is this better? We don't bombard them with new concepts until just before their use

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Why is this better? With a thorough understanding of semantics, new things (like syntactic sugar) are more readily digestible

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Thanks! Behind the Scenes X E L A TEX/ Beamer Pygments / Minted