Ruby introductions
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This document summarizes the history and key features of the Ruby programming language. It discusses: - The origins and early releases of Ruby from 1995 to 2007 in Japan and internationally. - Core aspects of Ruby including its object-oriented design, interpretation instead of compilation, duck typing approach, and inspiration from other languages like Perl and Python. - Fundamental Ruby concepts such as everything being an object, initialization methods, syntactic sugars, operator overloading, and private member variables with accessor methods. - Similarities and differences between Ruby and general programming language syntax for conditions, loops, exceptions, and meta-programming.
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Ruby introductions
- 2. Ruby.history() • Developed in Japan by Yukihiro "Matz" Matsumoto (only Japanese domestic ) • First public release in 1995(ver 0.95). • Ruby 1.6: September 2000 • By 2000, Ruby was more popular than Python in Japan • In September 2000, the first English language book Programming Ruby was printed • Ruby 1.8: released in August 2003 • July 2004, Hansson first released Ruby on Rails as open source • Ruby 1.9: December 2007 • Ruby 1.9 introduces many changes over the 1.8 series • Ruby 2.1 (was released on Christmas Day in 2013) 2 Actually, I didn't make the claim that Ruby follows the principle of least surprise. Someone felt the design of Ruby follows that philosophy, so they started saying that. I didn't bring that up, actually.
- 3. Ruby.is_a? • OOP language • Interpreted scripting language • Duck Typing style • Inspired Perl, Python, SmallTalk • Syntax is generally like all other programming languages 3
- 4. OOP Language • Everything, including a literal, is an object -199.abs # => 199 "ice is nice".length # => 11 "ruby is cool.".index("u") # => 1 • The constructor is always named “initialize” instead of the name of the class.
- 5. Interpreted scripting language • No compilation required
- 6. Duck typing and syntactic sugars • no need for type definition • There’s no casting. Just call the methods • no semicolons at the end of the line • no parentheses for method invocations • operators overload (operator_overload.rb) • getters/setters automatically • All member variables are private, Ruby have 3 methods: attr_accessor, attr_reader and attr_writer
- 7. Inspired Perl, Python, SmallTalk • Actual, I not yet do with Perl, so I am not sure about perl. In this chapter, I will compare with python • There’s an interactive prompt (called irb). • Indentation syntax (uses whitespace to delimit program blocks) • Objects are strongly and dynamically typed. • Everything is an object, and variables are just references to objects.
- 8. Syntax Generally its like all other programming languages, Except with a few syntax changes
- 9. Conditions • General if (condition){ # do xxx } else if (condition){ # do yyy } else { # do zzz } • Ruby if condition # … elseif condition # … else #… end b = a if condition unless condition # .. else # .. end
- 10. Loops • General while (condition){ #… } for(int i, i < array.length, i++){ #… } for each (String s : lst){ } • Ruby while i < 10 # … end until i == 10 # …. end people.each {|person| ….} people.each do |person| puts person.name end
- 11. Exception Handling • General try { # } catch (Exception e){ # } finally { # } • Ruby begin # rescue RuntimeException => e # rescue e # ensure # … end
- 12. Meta programming
- 13. Magic
- 14. Why ruby?
- 15. Why not ruby?