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.

1. Ruby
BinhBV
2014/03

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?