1. Why Ruby ? Hesham Kanany Hesham.Kanany@gmail.com

2. Scope History of Ruby. Where can you use Ruby? General Features.
Ruby: the Language.
Advantages using Ruby against other languages.
Some Coding Conventions.
Now what?

3. History of Ruby
Created (in Japan) by Yukihiro Matsumoto, popularly called Matz.
Matz has stated, "I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python. That's why I decided to design my own language"
Released to the public in 1995.
Licensed under GPL or Ruby terms.

4. About Ruby
Ruby is… A dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write.
At a Google Tech Talk in 2008 Matz further stated, "I hope to see Ruby help every programmer in the world to be productive, and to enjoy programming, and to be happy. That is the primary purpose of Ruby language.
Matz has often said that he is “trying to make Ruby natural, not simple,” in a way that mirrors life.
Building on this, he adds:
Ruby is simple in appearance, but is very complex inside, just like our human body.
Write more understandable code in less lines.

5. Where can you use Ruby? Text processing. web apps.
general system administration.
AI and math research.

6. General Features High level language.
True OO (everything’s an object!).
Interpreted.
Highly portable, works on Linux, UNIX, DOS, Windows 95/98/NT/2K, Mac, etc.

7. 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 any time (even during runtime) .
Allows operator overloading.
Can be extended with Ruby or low-level C.
No type declaration.

8. Advantages using Ruby against other languages
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.
Simple object get/set methods declaration.

9. Some Coding Conventions

10. Just in Ruby :) puts x if !x>5 puts x unless x>5 10.times do
End
5.upto 12 do
end
100.downto 32 do

11. Just in Ruby :) (continue)
cat=Animal.new('myCat')
def cat.sleep(mouse) #Define a function on the object level
End
class Animal
def name =(new_name)
@name =new_name
end
end # acts as a setter
dog=Animal.new('wolf')
dog.name() → 'wolf'
dog.name= 'lolo'
dog.name → 'lolo'

12. Ranges Inclusive range my_range = 1 .. 10
# Creates a range from 1 to 10
Non-inclusive range
my_range = 1 … 10
# Creates a range from 1 to 9
('cab'..'car').to_a
=> ["cab", "cac", "cad", "cae", "caf", "cag", "cah", "cai", "caj", "cak", "cal", "cam",
"can", "cao", "cap", "caq", "car"]

13. Data Type Conversion Converting to an Array: var_data_type.to_a
Converting to an String:
var_data_type.to_s
More (guess!):
var_data_type.to_i
var_data_type.to_f

14. Everything's an Object 5.to_s will return "5"
Methods can be applied to data directly – not just on variables holding data
Example:
5.to_s will return "5"

15. array_or_range = value array_or_range.each { |x|
Iterators
array_or_range = value
array_or_range.each { |x|
print x }
Example:
my_range = 1..5
my_range.each { |x|

16. Functions Functions begin with the keyword def
def function_name([args])
code block
end
Example:
def print_name(name='Ruby')
print name

17. OO Ruby Classes are containers for static data members and functions
Declared using the class keyword. All class names should begin with a capital letter
Constructor declared using the initialize keyword
Class variables precede with an
Objects created using the new method

18. Write simple Ruby programs Find a problem, and Ruby it!
Now what?
What you can do now?
Write simple Ruby programs
What you have to do?
Find a problem, and Ruby it!

19. Thank you!
Questions?