Download Ruby - OpenLoop.com

Presented By
Carl Zumbano and Sui Cheng
CS151 – Object Oriented Programming
May 10, 2001
Ruby: An Introduction
• Created by Yukihiro Matsumoto in 1993
(named after his birthstone)
• Inspired (in part) by Eiffel and Ada
• Pure OO language (even the number 1 is an
instance of a class)
• Highly portable, works on Linux, UNIX,
DOS, Windows 95/98/NT/2K, Mac, etc.
Ruby: An Introduction
• Freely available and open-source.
• More popular than Python in Japan,
probably b/c it handles mutibyte character
sets so easily.
• Syntax is readable and easy to learn.
• Being used for text processing, web apps,
general system administration, and AI and
math research.
Ruby: the Language
• No multiple inheritance, but modules allow
the importing of methods.
• Has garbage collection.
• Exception handling, like Java.
• Any class or instance can be extended
anytime (even during runtime)
• Allows operator overloading.
Ruby: the Language
• Can be extended with Ruby or low-level C.
• No type declaration.
• Has iterators, methods which accept blocks
for user-defined control structures (like
loops)
• Emacs, TextPad, and Vim all have support
available for Ruby.
Ruby: A Demonstration
#Person Class
class Person
attr_accessor :name, :age
def initialize(name, age)
@name = name
@age = age.to_i
end
def inspect
"#@name (#@age)"
end
end
#Usage of the class
p1 = Person.new('elmo', 4)
p2 = Person.new('zoe', 7)
#Results
p1 # -> elmo (4)
p2 # -> zoe (7)
Ruby: A Demonstration
Now let’s take a look at Ruby in action…
Ruby Vs Java / C++
• Ruby
• C++ / Java
– “Ruby”.length
– strlen(“Ruby”);
– s.length();
– -5.0.abs
– abs(-5.0);
– number =
Math.abs(number);
Advantages using Ruby against
Java and C++
• Allow pass by code block
• Support Regular Expression
• Cleaner code
– No need to declare variables
– Simple syntax (semi-colon is optional)
– Every thing is an object, even a number. No
need to call separate function.
– Simple object get/set methods declaration
Advantages (continue)
• Classes and modules are never closed.
• Better Access Control
– Dynamic access control
– Private methods never accessible directly by
another object
• Portable and extensible with third-party
library
• Interactive environment
Disadvantages using Ruby
against Java and C++
• No multiple inheritance
– However, Ruby offers multiple-inheritance-like
capabilities
• Ruby is a scripting language
– However, Ruby can access to OS features, do same
thing as Perl and Python
• Different syntax and method definition style
–
–
–
–
Return statement is optional
Use of expression interpretation
Braces not needed in control statements (if, while)
Instance variable must preceded by “@”
Disadvantages (continue)
• Potential thread starvation in multithreading
– Use in-process thread [non-native]
– However, it is lightweight and efficient
Closing
• Free download for Unix/Windows
• Applications includes:
– X11 window manager, GUIs, managing server
machines and databases.
• Want to know more:
– Visit http://www.ruby-lang.org
Ruby: References
• The Ruby Programming Language by Yukio
Matsumoto; Addison Wesley Professional,
2000.
• Programming Ruby: A Pragmatic
Programmer's Guide by David Thomas and
Andrew Hunt; Addison-Wesley Pub Co,
2000.