#Dev Sprint 8# ##Intro to Rails##

#0. Install Rails if you haven't#

gem install rails

#1. Get to Know Rails#

Visit the getting started tutorial at guides.rubyonrails.org. Give yourself a few hours to get through this; there is some Rails philosophy at the beginning and a lot of practice towards the end. This is going to be the foundation we build upon in week 9 when we create our own app from the ground up. Don't worry about a lot of the 'magic' you see; we will dig deeper when we do this next week. This is to get a taste of the way Rails is built, so that you will become familiar with the Rails vocabulary.

#2. Rails is not Ruby!#

Open the rails console (as described in #1 above). Try the following:

[[],nil,'',[nil]].each {|arg| puts "#{arg.blank?}"}
[[],nil,'',[nil]].each {|arg| puts "#{arg.present?}"}
[[],nil,'',[nil]].each {|arg| puts "#{arg.presence}"}
[1,'one',[1],['one'],nil].each {|arg| puts "#{arg.max}"}
[1,'one',[1],['one'],nil].each {|arg| puts "#{arg.try(:max)}"}
1.in?(1..3)
'alpha'.in?(['alpha','omega'])
Time.now
10.minutes.ago
Time.now - 10.hours

Many of these methods are very convenient...but do not actually exist in the ruby core. There's a whole article about it here.

Why point out that these methods are extensions of Ruby core? Well, many rails developers run into a problem when they start writing Ruby scripts and do not have access to the convenience methods in ActiveSupport. We'll do two (quick, promise!) exercises to illustrate this...

##Exercise 1: Triangles Redux##

Let's take the is_triangle? method from the dev-sprint7 repo and rewrite it using the rails convenience methods. Feel free to play around in console or check out the rails documentation of the Array class for some inspiration.

##Exercise 2: Secret Messages## ###"htslwfyaqfyntsx ts ijhtinsl ymj xjhwjy rjxxflj!"###

The string above was encoded using ROT-5, an encryption method that rotates, or shifts, the letters by 5 in one direction or the other.

Write a class, called Crypto, with class methods, that can take a string and, given an integer 'n', provide the ROT-n version of that string. A basic start might be:

class Crypto
  # make all methods class methods, so we can call them
  # using Crypto.method(arguments)
  class << self
    # You will probably need to store some information about the alphabet in this class somehow...
    # maybe a hash?

    # You should be able to use the same method to encode and decode...keep in mind that
    # to decode a shift of 5 to the 'right', you will need to shift 5 to the 'left'
    def shift_message(message, shift_factor)
      #Your code here
    end
  end
end

Let me know how your coding adventure went by posting an encrypted line, along with the shift factor, at the end of your pull request for this sprint.

###Challenge### Make it so your Crypto class doesn't barf when it runs into non-letters. ###Extra Challenge### Make it so your Crypto class preserves capital and lowercase letters (this can be trivial depending on how you do the first Challenge...I recommend checking out Regexp...specifically, find out what "A".match(/[A-Z]/) does as opposed to "a".match(/[a-z]/)).

Questions

Remember if you have any questions, post them to Piazza.

chrisvans/dev-sprint8

Questions