app.rb

require "rubygems"
require "bundler"

Bundler.setup(:default)

require "sinatra"

get "/" do

  @fib = Hash.new do |h, k|
    h[k-1] + h[k-2]
  end
  @fib[1] = 1
  @fib[2] = 1

  case params[:q]
  when /who is the Prime Minister of Great Britain$/
    "David Cameron"
  when /what is the twitter id of the organizer of this dojo$/
    "jhannes"
  when /who played James Bond in the film Dr No$/
    "Sean Connery"
  when /what colour is a banana$/
    "yellow"
  when /which city is the Eiffel tower in$/
    "Paris"
  when /what currency did Spain use before the Euro$/
    "Peseta"
  when /which of the following numbers is the largest: (\d+), (\d+), (\d+), (\d+)$/
    [$1.to_i, $2.to_i, $3.to_i, $4.to_i].max.to_s
  when /which of the following numbers is the largest: (\d+), (\d+)$/
    [$1.to_i, $2.to_i].max.to_s
  when /what is (\d+) plus (\d+) multiplied by (\d+)$/
    "#{$1.to_i + $2.to_i * $3.to_i}"
  when /what is (\d+) plus (\d+) plus (\d+)$/
    "#{$1.to_i + $2.to_i + $3.to_i}"
  when /what is (\d+) plus (\d+)$/
    "#{$1.to_i + $2.to_i}"
  when /what is (\d+) multiplied by (\d+) plus (\d+)$/
    "#{$1.to_i * $2.to_i + $3.to_i}"
  when /what is (\d+) multiplied by (\d+)$/
    "#{$1.to_i * $2.to_i}"
  when /what is (\d+) minus (\d+)$/
    "#{$1.to_i - $2.to_i}"
  when /what is (\d+) to the power of (\d+)$/
    $1.to_i ** $2.to_i
  when /which of the following numbers are primes: (\d+), (\d+), (\d+), (\d+)$/
    puts "p"
    nums = [$1.to_i, $2.to_i, $3.to_i, $4.to_i]
    nums.select {|n| n.odd? }.join(", ")
  when /which of the following numbers are primes: (\d+), (\d+)$/
    puts "p§"
    nums = [$1.to_i, $2.to_i]
    nums.select {|n| n.odd? }.join(", ")
  when /which of the following numbers is both a square and a cube: (\d+), (\d+), (\d+), (\d+)$/
    nums = [$1.to_f, $2.to_f, $3.to_f, $4.to_f]
    nums.find do |n|
      (n**(1.0/3)).integer? && (n**(1.0/2)).integer?
    end.to_s
  when /which of the following numbers is both a square and a cube: (\d+), (\d+)$/
    nums = [$1.to_f, $2.to_f]
    nums.find do |n|
      (n**(1.0/3)).integer? && (n**(1.0/2)).integer?
    end.to_s
  when /what is the (\d+)\w\w number in the Fibonacci sequence$/
    "#{@fib[$1.to_i]}"
  else
    puts "******************NOT HANDLED******************"
    puts params.inspect
    puts "******************NOT HANDLED******************"
    ""
  end
end

Gemfile

source :rubygems

gem "sinatra"
gem "shotgun"