Ruby Hell Yeah

“ A language that doesn’t affect the way you think about programming is not worth knowing” — Alan Perlis

Ruby? HELL YEAH! htttp://syamantics.com

./toc
What is Ruby?
Installing Ruby
Writing our first Ruby program
Ruby v/s PHP Syntax
What’s so special about Ruby??

What is Ruby?
A dynamic, object-oriented programming language that is way too different than C-type languages.
Inspired by LISP, Perl, SmallTalk
Simple, elegant, natural syntax
Created by Yukihiro Matsumoto, a.k.a. Matz

Installing Ruby
Windows
http://rubyforge.org/frs/?group_id=167
Ubuntu
sudo apt-get install ruby ri irb
You can even try out ruby online!
http://tryruby.hobix.com/

Our First Ruby Program
Open Your Interactive Ruby Shell
Open up Command Prompt/Shell/Terminal and type irb , then hit enter.
Now enter this,
puts "Hello World!"

Our Second Ruby Program
# The Greeter class
class Greeter
def initialize (name = "World" )
@name = name
end
def say_hi
puts "Hi #{ @name } !"
end
def say_bye
puts "Bye #{ @name } , see you next week."
end
end
# Initialize our Greeter
g = Greeter.new "Trippert Tech Session“
# Say hi
g .say_hi
# Say bye
g .say_bye

Ruby v/s PHP
Well, there are number of differences!
Ruby is fully OOP, PHP is not.
Ruby has got no primitive type, PHP has.
In Ruby, classes are objects, In PHP, classes are classes.
PHP function calls are Ruby messages.
Ruby uses sigil denotes for variable scoping.
Ruby has closures, anonymous functions, PHP does not*.
… . And many many many more.
There’s a create_function() function in PHP to create anonymous function though 

Ruby Syntax : Branches
if-else
switch case
if xtra_large
do_xtra_large
elsif large
do_large
elsif medium
do_medium
else #small
do_small
end
do_xtra_large if xtra_large
ending if

Ruby Syntax : Loops
for in
Iterators
for i in 1. .. 10
print i , " Hello " ;
end
projects = [ "Mobracer" , "GodFatherII" , "Tank" , "Madden Quiz" ]
projects .each do |project|
puts project
end
while i = 5 while i > 0 puts i i -= 1 end

Ruby Syntax : Containers
Arrays
Hashes
my_array = Array.new
my_array = []
my_array .push "One"
my_array .push "Two"
my_array = [ "One" , "Two" ,
"Three" , "Four" , "Five" ]
new_array = my_array[ 1. . 3 ]
new_array = my_array[ 1 , 3 ]
people = {
"linus" =>{ "lname" => "Torvalds" , "fname" => "Linus" , "project" => "Linux" },
"matz" =>{ "lname" => "Matsumoto" , "fname" => "Yukihiro" , "project" => "Ruby" },
"DHH" =>{ "lname" => "Hanmer Heinsen" , "fname" => "David" , "project" => "RoR" },
"nate" =>{ "lname" => "Abel" , "fname" => "Nate" , "project" => "CakePHP" }
}
people .select do |nick, info|
puts nick
info .select do |key, value|
puts key , value
end
end

Ruby Syntax : Subroutines, Modules
Subroutines
Modules
def doubleMe ( number )
number * 2
end
puts doubleMe 3
module MyMath
def doubleMe ( number )
number * 2
end
end
include MyMath
puts doubleMe 3
module MyMath TWO = 2 def MyMath .doubleMe( number ) number * TWO end end include MyMath puts MyMath .doubleMe 3 Modules

Ruby Syntax : Classes and Objects
Classes & Objects
class MyMath
def initialize
@two = 2
end
def doubleMe (number)
number * @two
end
end
my_math = MyMath.new
puts my_math .doubleMe 4

Ruby Syntax : Inheritance
Extending A Class
Including Modules
class MyParentMath
def initialize
@two = 2
end
number * @two
end
end
class MyChildMath < MyParentMath
def quadropoleMe (number)
doubleMe (number) * doubleMe(number)
end
end
my_math = MyChildMath.new
puts my_math .quadropoleMe 4
module MyMathModule
TWO = 2
number * TWO
end
end
class MyChildMath
include MyMathModule
def quadropoleMe (number)
doubleMe (number) * doubleMe(number)
end
end
my_math = MyChildMath.new
puts my_math .quadropoleMe 4

Ruby Syntax : Conventions
ClassNames
method_names and variable_names
methods_asking_a_question?
slightly_dangerous_methods!
@instance_variables
$global_variables
local_variable
SOME_CONSTANTS or OtherConstants

What’s so special about Ruby??
Introspection Close to Natural Language Method Redefinition Mixins
Implicit Singleton methods Meta-programming Dynamic typing
No Primitives Yield Powerful Fully Object Oriented
Flexible Symbols Minimalism DRY method_missing
Hooks Anonymous function Modules Multiple Inheritence Blocks
Reflection Closures Open objects Classes are objects
Dynamic Operator Overloading Open classes Sigil Denotes
Eval Simplicity Optional Parentheses Iterators attr_accessor
Syntactic Sugar Optional Punctuation Write Less Do More

TBC...

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Ruby Hell Yeah

by Anupom Syam on Aug 25, 2008

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