1. Ruby
Testing 2, 11/9/2004

2. What is Ruby?
Scripting language, developed by Yukihiro “Matz” Matsumoto
Current version = 1.8

3. Ruby Documentation Pickaxe book (shown last class)
ri command
ri <Class name>
Ruby Cheat Sheet (on blackboard)

4. Running Ruby Command line Eclipse SciTE irb ruby –w <file name>
More later
SciTE
Demo
irb

5. Ruby in Eclipse
Download Ruby Development Tool from
Nowhere near the functionality of Java in Eclipse
In preferences, set path to ruby bin directory

6. Ruby Basics Everything is an object
Comments start with # and go until end of line
Methods are created using def…end

7. Ruby Naming Initial letter Multi-word names End characters
Local variables, method parameters, and method names  lowercase letter or underscore
Global variable  $
Instance variable
Class variable 
Class names, module names, constants  uppercase letter
Multi-word names
Instance variables  separate words with underscores
Class names  use MixedCase
End characters
? Indicates method that returns true or false to a query
! Indicates method that modifies the object in place rather than returning a copy

8. Blocks Allow passing chunks of code in to methods
Single line blocks enclosed in {}
Multi-line blocks enclosed in do…end
Receiving method uses “yield” command to call passed code (can call yield multiple times)
Can use parameters
[ 1, 3, 4, 7, 9 ].each {|i| puts i }

9. Strings in Ruby Quotes matter!
Strings in “” (double quotes) have replacement processing on them
\<char> replacement (like C -- \n = newline, etc)
Expression replacement (“Variable x = #{x}” would have the value of x substituted for the #{x})
Strings in ‘’ (single quotes) are treated as literals with no processing
Strings in `` (back ticks) are treated as commands to be executed by the operating system

10. Control structures If…elsif…else…end unless <condition> … end
while <condition>… end
until <condition>… end
case when <condition> then <value>… else… end
#.times (e.g. 5.times())
#.upto(#) (e.g. 3.upto(6))
<collection>.each {block}

11. Ruby equivalents in Java
null
toString()
extends
constructor name = class name
try…catch
import
Ruby
nil
to_s
<
constructor name = initialize
begin…end…rescue
require

12. Test::Unit Very similar to JUnit require ‘test/unit’
Class MyTestClass < Test::Unit::TestCase
Use “flunk” instead of JUnit’s “fail”