fizzbuzz.rb

class Proc
#This defines a method that can allow the case equality === http://www.ruby-doc.org/core-2.1.1/Proc.html#method-i-3D-3D-3D be called on 2 proc objects
  def &o
   ->(a) { call(a) && o[a] }
  end
end

def multiple_of(x)
#A partial function http://en.wikipedia.org/wiki/Partial_function
  ->(a) { a % x == 0 }
end

(1..100).each do |x|
  case x
  when multiple_of(3) & multiple_of(5) 
  #elegance of the & method defined on the proc object shows ... multiple_of(3) returns
  #->(a) { a % 3 == 0 }
  #multiple_of(5) returns ->(a) { a % 5 == 0 }
  #both are combined with the & to return something similar to ->(a) { (->(a) {  a % 3 == 0 }) && ->(a) { a % 5 == 0 } }
  #ruby now calls this new proc object with x to return a truthy or falsy value to determine if it should continue to the next line of the switch
    puts "FizzBuzz"
  when multiple_of(3)
    puts "Fizz"
  when multiple_of(5)
    puts "Buzz"
  else
	puts x
  end
end