Seven Languages in Seven Months: Ruby presentation

_setup.txt

git clone git://gist.github.com/3944262.git seven_langs_ruby
cd seven_langs_ruby
gem install gli -v 1.6.0
gem install showoff
showoff serve
open "http://localhost:9090"

ruby.md

!SLIDE

Seven Languages in Seven Months: Ruby

Aidan Feldman

Jux.com

Slides at: gist.github.com/3944262

!SLIDE

Background

• Created in 1993 in Japan by Yukihiro Matsumoto ("Matz")
• Inspired by Lisp, Smalltalk & Perl
• Emphasis on programmer productivity
• Gained in popularity w/ Rails ca. 2006

!SLIDE

Overview

• Interpreted, object-oriented, dynamically/duck-typed
• Balances "functional programming with imperative programming"
• Flexible syntax
• [Almost] everything is an expression^

!SLIDE

Expression vs. Statement

• "Statements do not return results and are executed solely for their side effects, while expressions always return a result"
• "Expressions have a value, statements do not"

!SLIDE

Everything is an Object

@@@ ruby
6.is_a? Object
nil.is_a? Object

a = Object.new
a.is_a? Object

Class.is_a? Object
Object.is_a? Object

!SLIDE

Blocks

Lisp-y, without the parens.

@@@ ruby
search_engines =
  %w[Google Yahoo MSN].map do |engine|
    "http://www." + engine.downcase + ".com"
  end

!SLIDE

Mixins

Alternative to multiple inheritance, e.g. Enumerable.

@@@ ruby
class Family
  include Enumerable

  attr_accessor :surname
  attr_accessor :father, :mother, :child

  def each
    yield "#{@father} #{@surname}"
    yield "#{@mother} #{@surname}"
    yield "#{@child} #{@surname}"
  end
end

f = Family.new
f.surname = 'Smith'
f.father = 'Bob'
f.mother = 'Alice'
f.child = 'Carol'

f.each do|person|
  puts person
end

puts f.include?('Bob Smith')

c/o Michael Morin

!SLIDE

Things to Notice

• Instance variables
  • @foo
• Getters/setters
  • f.surname
  • f.surname = 'Smith'
• String interpolation
  • "#{first} #{last}"

!SLIDE

Syntactic Sugar

• Operations (including arithmetic) are simply methods
• Parentheses often optional
• Methods and properties are somewhat interchangeable.
• Operators in english, e.g. unless, and, or

ex.

@@@ ruby
'foo bar'.split.size.to_s + ' words'

!SLIDE

Monkey-Patching

Add functionality to previously-defined classes.

@@@ ruby
class Fixnum
  def k
    self * 1000
  end
end

puts 10
puts 10.k

…or override.

@@@ ruby
class Fixnum
  def +(x)
    self.-(x)
  end
end

puts 3 + 2

!SLIDE

MetaProgramming

@@@ ruby
Kernel.const_get('Array').new

6.methods
6.respond_to? :to_s
6.send :to_s
6.method(:to_s).call


class Family
  attr_accessor :surname
  attr_accessor :father, :mother

  def method_missing(meth)
    if meth.to_s =~ /^(\w+)_full$/
      "#{self.send($1)} #{self.surname}"
    else
      super
    end
  end
end

f = Family.new
f.surname = 'Smith'
f.father = 'Bob'
f.mother = 'Alice'

f.father_full
f.mother_full
f.son_full

!SLIDE

Fin.

Aidan Feldman

@aidanfeldman

afeld.me

showoff.css

#preso,
.slide {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: auto;
  height: auto;
  overflow: auto;
}

pre.sh_sourceCode {
  font-size: 2.5em;
}