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Sony Fermino dos Santos

  • Physicist
  • Programmer
  • Systems Analyst
  • Civil Servant
  • Writer

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About Ruby

  • Japan, 1995, Yukihiro "Matz" Matsumoto
  • Functional, OO, imperative, reflective
  • Python, Perl, Smalltalk, Eiffel, Ada and Lisp

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puts "Hello World!"

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My Evolution

  • Until 2000: BASIC, Clipper, Z80 Assembly, Pascal, C, C++...
  • After 2000:
    • Delphi
    • PHP (and CSS, JS, MySQL)
    • Ruby

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Delphi

Pros:

  • easy to design
  • practical for programming
  • ideal for Windows

Cons:

  • instalation on several machines
  • double work: screens and reports

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PHP - Pros

  • easy to learn and to program
  • ready for web
  • flexible
  • free (as in speech and in beer)
  • you just pass the link to users
  • screens (pages) == reports

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PHP - Cons

  • polluted namespace: array_*(...)
  • very complex when project’s size increases
  • so much typing
  • not a native OO language

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Adding fruits to the basket - PHP

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Adding fruits to the basket - Ruby

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Adding fruits in chunks

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Adding fruits in chunks

PHP:

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​

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Ruby:

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Python vs Ruby: Personal Appeals

Python:

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Python vs Ruby: Personal Appeals

Python: Ruby:

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Speaking Dog

Python:

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Speaking Dog

Python: Ruby:

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Ruby Object Model

BasicObject

Object

Module

Class

Kernel

String

Fixnum

"love"

1337

is instance of Object

is subclass of Class

includes Module

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Open Classes

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Open Classes

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Open Classes

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Open Classes

Solution: Refinements!

(since Ruby 2.0)

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Ruby Gems

Gem (precious stone, as ruby is):

  • groups features that can be reused in other projects;
  • allows easy sharing with other developers for free (rubygems.org).

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gem install mysql2 sequel sinatra mail sqlite3

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rubygems.org

Gems Public Library

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DSL: Domain-Specific Language

You can create another language inside Ruby to work more directly in a specific domain

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Sequel DSL for SQL

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Sequel DSL for SQL

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Sinatra DSL for web apps

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Ruby Best Practices

  • Conventions
  • Benchmark
  • Unit Testing
    • Test::Unit, RSpec, Shoulda, Expectations…
  • Documentation
    • RDoc, ri, YARD...

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Best Practices: Benchmark

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Best Practices: Unit Testing

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Best Practices: Documentation

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Front-end in Ruby

http://opalrb.org/

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Ruby drawbacks

  • Many ways to do the same thing
    • requires to analyse which way reaches the best result, which is more recommended, which is faster, which is more quick to program, which is more maintenable...
    • benchmark tests
    • research in blogs, forums, StackOverflow, etc.
  • Methods that return a valid object or nil
    • you can program your methods, but many built-in classes’ methods return a valid object or nil, so you have to check for nil frequently.
  • backtrace doesn’t show the parameters’ values
    • it would turn the debugging process much easier

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Installing

  • Your linux native package manager
    • apt-get, rpm, yum…
  • Ruby Versions Manager
    • RVM, rbenv
  • Docker
    • docker pull ruby:2.3.1
    • see https://hub.docker.com/_/ruby/
  • RubyInstaller (Windows)

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Documentation and Tutorials

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The End

sony.fermino@gmail.com

http://rubychallenger.blogspot.com.br/

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