Ruby Programming Language - Introduction
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Ruby is an interpreted, object-oriented, and dynamically typed programming language. It was created in the 1990s by Yukihiro Matsumoto to enhance programmer productivity and have fun. Some key aspects include everything being an object, duck typing where objects are identified by their methods/attributes rather than type, and a focus on simplicity, readability, and productivity for programmers.
![Ruby: Object-Oriented Language
Encapsulation
[State & Behavior] : Packaged together
Inheritance
[Class Tree] : Object types are organized
Polymorphism
[Many Forms]
: Objects can be shown
Image Source: What Is an Object?
Image Source: What Is Inheritance?Image Source: Object-Oriented Concepts](https://image.slidesharecdn.com/rubyprogramminglanguage-introduction-150628082112-lva1-app6892/85/Ruby-Programming-Language-Introduction-12-320.jpg)
![Ruby: Pure Object-Oriented Language
Ruby Programming Language
Everything is an object!
Compare: Java Programming Language
Primitive types (int, char, ……) are not objects!
D:Ruby22bin>irb
irb(main):001:0> 4
=> 4
irb(main):002:0> 4.class
=> Fixnum
irb(main):003:0> 4 + 4
=> 8
irb(main):004:0> 4.methods
=> [:to_s, :inspect, :-
@, :+, ∙∙∙∙∙∙, :__id__]
irb(main):005:0>](https://image.slidesharecdn.com/rubyprogramminglanguage-introduction-150628082112-lva1-app6892/85/Ruby-Programming-Language-Introduction-13-320.jpg)
![Ruby: Duck Typing Code Example
D:Ruby22bin>irb
irb(main):001:0> i = 0
=> 0
irb(main):002:0> a = ['100', 100.0]
=> ["100", 100.0]
irb(main):003:0> while i < 2
irb(main):004:1> puts a[i].to_i
irb(main):005:1> i = i + 1
irb(main):006:1> end
100
100
=> nil
irb(main):007:0>
We consider this to_i method as quack!
Duck typing doesn’t care
what the underlying type might be
(whether string or float).
string
float](https://image.slidesharecdn.com/rubyprogramminglanguage-introduction-150628082112-lva1-app6892/85/Ruby-Programming-Language-Introduction-16-320.jpg)
![Ruby: Sample Code
D:Ruby22bin>ruby
properties = ['object oriented', 'duck typed', 'productive', 'fun']
properties.each {|property| puts "Ruby is #{property}."}
^D
Ruby is object oriented.
Ruby is duck typed.
Ruby is productive.
Ruby is fun.
D:Ruby22bin>](https://image.slidesharecdn.com/rubyprogramminglanguage-introduction-150628082112-lva1-app6892/85/Ruby-Programming-Language-Introduction-18-320.jpg)
Ruby Programming Language - Introduction
- 1. Ruby Programming Language Introduction 28 Jun 2015 Kwangshin Oh [email protected] http://kwangshin.pe.kr
- 2. Seven Languages in Seven Weeks A Pragmatic Guide to Learning Programming Languages By Bruce A. Tate
- 3. Why New Programming Language? “Learning a new programming language will show you new ways of thinking, and new approaches to problem solving that will help you be a better programmer in any language.” - Pragmatic Bookshelf “Ultimately, programming is about understanding, and understanding is about ideas. So, exposure to new ideas is essential to a deeper understanding of what programming is all about.” - Foreword By Joe Armstrong, creator of Erlang
- 4. Agenda Ruby is… History & Why? With a Spoonful of Sugar So, Ruby is… Ruby: Interpreted Language Ruby: Interpreted Language – Example Compare: Compiled Language - Java Ruby: Object-Oriented Language Ruby: Pure Object-Oriented Language Ruby: Dynamically Typed Language What is Duck Typing? Ruby: Duck Typing Code Example Download & Installation Ruby Code Reference
- 5. Ruby is… Programming Language! Dynamic Open Source Focus on… Simplicity Productivity Has an elegant syntax Natural to read Easy to write Image Source: Ruby Programming Language
- 6. History & Why? Ruby’s Creator Yukihiro “Matz” Matsumoto Created in about 1993 Motivation The primary motivation was to amuse himself! Just a hobby at the beginning New object-oriented language that combines characteristics from Lisp, Smalltalk and Perl To enhance programmers’ productivity “Ruby is simple in appearance, but is very complex inside, just like our human body.” - Matz, speaking on the Ruby-Talk mailing list, May 12th, 2000. Image Source: Ruby Everywhere
- 7. With a Spoonful of Sugar Ruby with more syntactic sugar Makes code easier to read and write Focus on the efficiency of the programmers “A spoonful of sugar makes the medicine go down.” Mary Poppins Image Source: Disney Wiki – A Spoonful of Sugar
- 8. So, Ruby is… Interpreted Language Ruby code is executed by an interpreter Object-Oriented Language Encapsulation Inheritance Polymorphism Dynamically Typed Language Types are bound at execution time Image Source: Skillcrush - Ruby
- 9. Interactive Console Ruby File (*.rb) Ruby: Interpreted Language Image Source: http://www.iconsdb.com, http://dryicons.com and http://findicons.com Ruby Interpreter
- 10. Interactive Console Ruby File (Ha.rb) Ruby: Interpreted Language - Example D:Ruby22bin>type Ha.rb 3.Times do print “Ha “ end D:Ruby22bin>ruby Ha.rb Ha Ha Ha D:Ruby22bin> D:Ruby22bin>ruby 3.Times do print “Ha “ end ^D Ha Ha Ha D:Ruby22bin>
- 11. Compare: Compiled Language - Java Java Source File (*.java) Java Compiler Java Class File (*.class) JRE (Java Runtime Environment)
- 12. Ruby: Object-Oriented Language Encapsulation [State & Behavior] : Packaged together Inheritance [Class Tree] : Object types are organized Polymorphism [Many Forms] : Objects can be shown Image Source: What Is an Object? Image Source: What Is Inheritance?Image Source: Object-Oriented Concepts
- 13. Ruby: Pure Object-Oriented Language Ruby Programming Language Everything is an object! Compare: Java Programming Language Primitive types (int, char, ……) are not objects! D:Ruby22bin>irb irb(main):001:0> 4 => 4 irb(main):002:0> 4.class => Fixnum irb(main):003:0> 4 + 4 => 8 irb(main):004:0> 4.methods => [:to_s, :inspect, :- @, :+, ∙∙∙∙∙∙, :__id__] irb(main):005:0>
- 14. Ruby: Dynamically Typed Language Types are bound at execution time Flexibility Execution Safety Types are bound at compile time Flexibility Execution Safety Dynamically Typed Statically Typed Java
- 15. What is Duck Typing? Quacks like a duck Swims like a duck Walks like a duck Call it a duck “When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.” - James Whitcomb Riley Image Source: https://www.iconfinder.com and http://www.vectors4all.net/
- 16. Ruby: Duck Typing Code Example D:Ruby22bin>irb irb(main):001:0> i = 0 => 0 irb(main):002:0> a = ['100', 100.0] => ["100", 100.0] irb(main):003:0> while i < 2 irb(main):004:1> puts a[i].to_i irb(main):005:1> i = i + 1 irb(main):006:1> end 100 100 => nil irb(main):007:0> We consider this to_i method as quack! Duck typing doesn’t care what the underlying type might be (whether string or float). string float
- 17. Download & Installation Current Stable Version Ruby 2.2.2 (As of 28 Jun 2015) Windows RubyInstaller - http://rubyinstaller.org/downloads/ OS X Homebrew - http://brew.sh/ Debian GNU/Linux and Ubuntu apt – command : $ sudo apt-get install ruby-full CentOS, Fedora, and RHEL yum – command :$ sudo yum install ruby
- 18. Ruby: Sample Code D:Ruby22bin>ruby properties = ['object oriented', 'duck typed', 'productive', 'fun'] properties.each {|property| puts "Ruby is #{property}."} ^D Ruby is object oriented. Ruby is duck typed. Ruby is productive. Ruby is fun. D:Ruby22bin>
- 19. Ruby Code: Hello World! D:Ruby22bin>irb irb(main):001:0> puts 'Hello World!' Hello World! => nil irb(main):002:0> language = 'Ruby' => "Ruby" irb(main):003:0> puts "Hello, #{language}" Hello, Ruby => nil irb(main):004:0> language = 'my Ruby' => "my Ruby" irb(main):005:0> puts "Hello, #{language}" Hello, my Ruby => nil irb(main):006:0> Ruby’s Interactive Console <One Quote String> Interpreted Literally <Two Quotes String> String Evaluation
- 20. Ruby Code: Comparison Operators D:Ruby22bin>irb irb(main):001:0> x = 4 => 4 irb(main):002:0> x < 5 => true irb(main):003:0> x > 4 => false irb(main):004:0> false.class => FalseClass irb(main):005:0> true.class => TrueClass irb(main):006:0> puts 'X value is equal to 4.' if x == 4 X value is equal to 4. => nil irb(main):007:0> Everything is an object in Ruby!
- 21. Ruby Code: Loops – until & while D:Ruby22bin>irb irb(main):001:0> x = 5 => 5 irb(main):002:0> x = x - 1 until x == 1 => nil irb(main):003:0> x => 1 irb(main):004:0> while x < 5 irb(main):005:1> x = x + 1 irb(main):006:1> puts x irb(main):007:1> end 2 3 4 5 => nil
- 22. Ruby Code: Expressions - true & false D:Ruby22bin>irb irb(main):001:0> puts '1 is true in Ruby' if 1 1 is true in Ruby => nil irb(main):002:0> puts 'String is true in Ruby' if 'Kwangshin Oh' (irb):2: warning: string literal in condition String is true in Ruby => nil irb(main):003:0> puts '0 is also true in Ruby' if 0 0 is also true in Ruby => nil irb(main):004:0> puts 'The false is false in Ruby' if false => nil irb(main):005:0> puts 'The nil is false in Ruby' if nil => nil irb(main):006:0> Everything ( but nil and false ) evaluate to true!
- 23. Reference Seven Languages in Seven Weeks: A Pragmatic Guide to Learning Programming Language by Bruce A. Tate https://pragprog.com/book/btlang/seven-languages-in-seven-weeks Ruby Programming Language https://www.ruby-lang.org/ Ruby-Talk mailing list, May 12th, 2000 http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/2773 Disney Wiki – A Spoonful of Sugar http://disney.wikia.com/wiki/A_Spoonful_of_Sugar Matzにっき (Matz Diary) http://www.rubyist.net/~matz/ The Java™ Tutorials - Object-Oriented Programming Concepts https://docs.oracle.com/javase/tutorial/java/concepts/index.html Duck typing https://en.wikipedia.org/wiki/Duck_typing