Ruby

Class

The Ruby Language

• Originally by Yukihiro "Matz" Matsumoto• “Ruby is designed for programmer

productivity and fun, following the principles of good user interface design. He stresses that systems design needs to emphasize human, rather than computer, needs.”

http://en.wikipedia.org/wiki/Ruby_(programming_language)#History

• Ruby 1.0 was released in 1996.

The Ruby Language

• Dynamically typed• Interpreted• Can be modified at runtime• Object oriented• Blocks & lambdas• Nice support for Regular Expressions

Ruby Implementations

• Ruby 1.8.x (MRI)• Ruby 1.9.x (YARV)• Rubinius• JRuby• MacRuby, HotCocoa• IronRuby for .NET

What you will learn

• Ruby– Language concepts & tools– Language syntax– Some standard library classes & gems– Common patterns

Book

• The Well-Grounded RubyistCovering Ruby 1.9

David A. Black

How you will learn

• Exploration: experiment, play• Test-Driven Development (TDD)– Initially as a learning methodology– Later as a development methodology

• Ask questions• Learn to find your own answers• Read

• Plus whatever works best for you

Class Structure

• Talk• Live Coding Demonstrations• In-class coding• Coding at home (or in social groups)• Google Group

Other Resources

• SF Ruby Meetup• RailsBridge

See Last page of hand-out for more

Class Topics

Class 1 Introduction to RubyTest First Teaching Introduction to RSpec and Git

Class 2 Conditionals, Iterators (Hashes & Arrays) & Blocks

Class 3 Strings, Regex and Web Requests

Class 4 Files and Enumerables

Class 5 Performance

Class 6 Memory footprint, Building a gem

Ruby Language Overview

• Dynamically typed• Interpreted• Can be modified at runtime• Object oriented• Blocks & lambdas• Nice support for Regular Expressions

Lets get started

• IRB: InteractiveRuBy>> 4>> 4 + 4

Everything is an object

“test”.upcase“test”.class“test”.methods

Everything evaluates to something

2 + 2(2+2).zero?

Methods are Messages

thing.do(4)thing.do 4thing.send “do”, 4

Operators are Methods

thing.do 4thing.do(4)thing.send “do”, 4

1 + 21.+(2)1.send "+", 2

Write your first Ruby class

Test-First Learning

• Similar methodology to TDDwith a different purpose and workflow

• Teacher writes the test• Student implements the code

Test-Driven Development

• Design• Focus / Project Management• Documentation / Collaboration• Creation of Tests

Moving to TDD

• Build tests before refactoring or upgrading• Test-drive bug fixes• Write tests for anything you worry about• Continuous Integration is essential• Remove unused (untested) code

RED – GREEN – REFACTOR

1. Write the test2. Watch it fail3. Make it pass4. Make the code good, make sure it still passes

Unit Test Frameworks

• Test::Unit• Shoulda• Rspec

http://github.com/ultrasaurus/test-framework-comparison

Integration Test Frameworks

• Cucumber• Webrat• Selenium• And more…

Rspec

• Describe the feature• Verify expectation

Demonstration