Carl%20Zumbano%20and%20Sui%20Cheng

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Presented By Carl Zumbano and Sui Cheng
CS151 Object Oriented Programming May 10, 2001
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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.

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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.

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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.

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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.

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Ruby A Demonstration
Person Class class Person attr_accessor name,
age def initialize(name, age) _at_name name
_at_age age.to_i end def inspect "_at_name
(_at_age)" end end Usage of the class p1
Person.new('elmo', 4) p2 Person.new('zoe', 7)
Results p1 -gt elmo (4) p2 -gt zoe (7)
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Ruby A Demonstration
Now lets take a look at Ruby in action
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Ruby Vs Java / C

• Ruby
• Ruby.length
• -5.0.abs

• C / Java
• strlen(Ruby)
• s.length()
• abs(-5.0)
• number Math.abs(number)

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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

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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

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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 _at_

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Disadvantages (continue)

• Potential thread starvation in multi-threading
• Use in-process thread non-native
• However, it is lightweight and efficient

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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

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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.