Hello Ruby - Speaker Deck

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Hello Ruby :) Felipe Pelizaro Gentil @fpgentil Carlos Eduardo Ribeiro @duduribeiro

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ruby /ˈruːbi/

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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. https://www.ruby-lang.org/en/documentation/

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Reserved words

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Ruby Version Manager (RVM) RVM is a command-line tool which allows you to easily install, manage, and work with multiple ruby $ gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 $ curl -sSL https://get.rvm.io | bash -s stable https://github.com/rvm/rvm

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IRB … stands for “interactive Ruby” and is a tool to interactively execute Ruby expressions read from the standard input. $ irb

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Methods

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if / unless

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Loops

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or || && and http://devblog.avdi.org/2010/08/02/using-and-and-or-in-ruby/ and is useful for chaining related operations together until one of them returns nil or false or is useful for chaining expressions together. The best way to think about the chains constructed with or is as series of fallbacks: try this, if that fails try this, and so on. For instance:

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||= Double Pipe / Or Equals http://www.rubyinside.com/what-rubys-double-pipe-or-equals-really-does-5488.html

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Array

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Hash

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Symbols Symbol objects represent names and some strings inside the Ruby interpreter

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map http://railspikes.com/2008/8/11/understanding-map-and-reduce Returns a new array with the results of running block once for every element in enum. http://apidock.com/ruby/Enumerable/map

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reduce / inject http://railspikes.com/2008/8/11/understanding-map-and-reduce Combines all elements of enum by applying a binary operation, speciﬁed by a block or a symbol that names a method or operator.

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reduce / inject http://apidock.com/ruby/v1_9_3_392/Enumerable/inject

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attr_accessor attr_writer attr_reader defines getter and setter defines only getter defines only setter

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Classes

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Opening Classes

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Clojures function that can be stored as a variable

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Ruby and its 4 types of clojures Blocks Procedures (aka Procs) lambdas Method Objects

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Blocks

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Procedures (Procs) a block that can be saved for reusable code

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lambdas • a Proc that check the number of arguments • Diminutive return, in other words, a Proc return will stop   a method, lambdas will return their value and let the method   continue

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Method Objects

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Exercises • Generate a Fibonacci sequence in an array until 500 • Create a method that receives N parameter and return their sum • Create a method that receives a string and check if its a palindrome

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Fibonacci

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Sum

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Palindrome

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Gems • What? essentially a Ruby plugin • Why? code reuse as open-source, it provides others the opportunity  to contribute by adding features • How? $ gem install bundler $ bundle gem my_gem

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RubyGems

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Tests!!!!!!!!

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Rspec / Minitest http://tenderlovemaking.com/2015/01/23/my-experience-with-minitest-and-rspec.html

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Rspec / Minitest https://github.com/rspec/rspec https://github.com/seattlerb/minitest

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Exercise Create a GEM that performs the 4 basic math operations - SUM - SUBTRACTION - MULTIPLICATION - DIVISION Tip: folder already created ~/Desktop/Hello Ruby/hello_ruby_calculator

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