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Agenda

10:30 - 1 Ruby tools of the trade 2-4:30 Building a program for 4:30 - 5 Q & A

DBLMG/SoFree, Ruby History

  • Februray 24, 1993
  • 1.8 is the first of the "Modern Versions"

Props of Lang

  • writeen in C
  • Uses its own specific Virtual Machine
  • interpreted NOT compiled

True OOL

  • Models things, NOT process
  • Follows many SmallTalk principles

Tools of the Trade

  • Interactive Ruby (IRB)
  $ irb
  irb(main):001:0> puts RUBY_PLATFORM
  x86_64-darwin13.3.0
  => nil
  irb(main):002:0> puts RUBY_VERSION

  irb(main):007:0> s = "hello"
  => "hello"
  irb(main):008:0> s.class
  => String
  irb(main):009:0> s.kind_of?(String)
  => true
  irb(main):010:0> puts s.upcase
  HELLO
  => nil
  • gem
    • like rpm command
  • bundler
    • kinda like yum
    • gem management
    • used to tie your project with the require gems
  • rake
    • task automation
    • help with routine tasks
  • rspec
    • TDD (write first, then code)
    • Great tool for API
    • helps reduce regressions
  • cucumber
    • BDD (better at testing behaviour)
    • better for Customer facing aspects?
    • own lang - Gherkin
  • Aruba
    • BDD
    • Adds to current Cucumber Installation
    • grest for testing command line apps
  • Binman
    • Write your page in MarkDown
    • Add it to your program
    • Use to produce man page for yoru app
    • JAVADoc for ruby
  • JSON
    • Uses native Ruby format to reps data

Syntax

  • Ternary (Single Line If/Then/Else)
  x = something ? 5 : 0

   same as

  if something == true
    x = 5
  else
    x = 0
  end
  • Unless
  unless something

    same as

  if something = FALSE
  • Modified if
  x = 5 if something

    same as

  if something = true
    x = 5
  end
  • while vs until
    • until is a neg (or NOT) for while (i.e. while ! a.empty something)
  • times loop
    • multiple lines use "do/end"
    • sinle line use "{}"
  • each -- iterator
  • flip flop
  irb(main):001:0> (1..10).each do |x|
  irb(main):002:1* puts x if x==4..x==8
  irb(main):003:1> end

Declaration

  • Global Variables
  • Class Variables
    • At class, not instance level
    • begin with "@@"
  • Instances Variables
    • defined once for every instatiated class/module
    • begins with "@"

Class Properties

  • Getter
    • Used by other object to "read" a property
attr_reader :color
  • Setter
    • Used by other objects to "write" a new value to a property
attr_writer :color
  • Read & Write
    • does both what seter and getter do
attr_accessor :color

Class

Exceptions

  • "begin" instead of try
  • "rescue" instaed of ctach
  • "raise" instande of throw

Enumerations

  • select
  • reject
  • collect (alias map)
  • detect (alias find)
  • inject

Disk & network i/o operation

  • file
    • file.open
    • file.close
    • file.read
  • http
    • Net::HTTP library
    • wraps the HTML API
    • Net::HTTPS for secure
  • ftp
    • net::ftp module
    • upload/download files
    • fully wraps ftp protocol
  • scp
    • uses Net::SSH & Net::SCP libs

Testing our code...

irb

require "json" require_relative "lib/portfolio" fcont = File.open("data/portfolio.json").read() data = JSON.parse(fcont) port = Porfolio.new(data)

-- Looking into the data port.class s1 = port.stocks s1.class ms = s1["MSFT"]