Early Steps

>> reg_chal = RegexpChallenge.new
No challenges.
=> 
>> reg_chal.challenge("Gray, James", "James", "The names can vary.")
=> nil
>> reg_chal.challenge("abbbbbbbc bc", 10)
=> nil
>> reg_chal.challenge( "    \n\t  ", nil,
?>                     "We want to test for non-space data." )
=> nil
>> reg_chal.challenge( "cogs 9, widgets 12, ...", "12",
?>                     "The numbers can vary." )
=> nil
>> reg_chal.challenge( "I'm a simple sentence, with words.",
?>                     %w[I'm a simple sentence with words] )
=> nil

>> reg_chal.challenges
Challenge #0:
   Input:  "Gray, James"
  Output:  "James"
    Note:  "The names can vary."
Challenge #1:
   Input:  "abbbbbbbc bc"
  Output:  10
Challenge #2:
   Input:  "    \n\t  "
  Output:  nil
    Note:  "We want to test for non-space data."
Challenge #3:
   Input:  "cogs 9, widgets 12, ..."
  Output:  "12"
    Note:  "The numbers can vary."
Challenge #4:
   Input:  "I'm a simple sentence, with words."
  Output:  ["I'm", "a", "simple", "sentence", "with", "words"]
=> nil

>> reg_chal.solve(0, :=~, /, \w+/)
That is not a valid solution.
Expected output:  "James"
    Your output:  4
=> nil
>> reg_chal.solve(0, :[], /\w+$/)
Correct.  Nice job.
=> nil
>> reg_chal.solutions
Solution #0:
     Input:  "Gray, James"
    Output:  "James"
      Note:  "The names can vary."
  Solution:  [](/\w+$/)
=> nil

reg_chal = RegexpChallenge.host

reg_chal = RegexpChallenge.join("HOST IP ADDRESS HERE")

#!/usr/bin/env ruby -w

require "yaml"
require "drb"

$SAFE = 1
PORT  = 61676

class RegexpChallenge
  def self.host(challenges = nil)
    hosted_challenges = challenges || new
    DRb.start_service("druby://0.0.0.0:#{PORT}", hosted_challenges)
    puts "Now serving challenges on port #{PORT}..."
    hosted_challenges
  end

  def self.join(ip_address)
    DRb.start_service
    puts "Connecting to challenges on port #{PORT} at IP #{ip_address}..."
    challenges = DRbObject.new_with_uri("druby://#{ip_address}:#{PORT}")
    $stdout.extend(DRbUndumped)
    challenges.drb_stdout = $stdout
    challenges
  end

  def self.load(file_name = "regexp_challenge.yaml")
    File.open(file_name) { |file| YAML.load(file) }
  end

  def initialize
    @challenges = Array.new
    @solutions  = Array.new

    @drb_stdout = nil
  end

  attr_writer :drb_stdout

  def io
    if caller.any? { |call| call =~ /\bdrb\b/ }
      @drb_stdout || $stdout
    else
      $stdout
    end
  end

  def challenge(input, output, note = nil)
    @challenges << [input, output, note] and nil
  end

  def challenges
    if @challenges.empty?
      io.puts "No challenges."
    else
      @challenges.each_with_index do |challenge, i|
        io.puts describe_challenge(challenge, i)
      end
    end && nil
  end
  alias_method :inspect, :challenges

  def solve(challenge_number, method_call, regexp, *additional_args)
    answer = @challenges[challenge_number][0].send( method_call,
                                                    regexp,
                                                    *additional_args )
    if answer == @challenges[challenge_number][1]
      io.puts "Correct.  Nice job."
      @solutions << @challenges.slice!(challenge_number) + [ method_call,
                                                             regexp,
                                                             additional_args ]
    else
      io.puts "That is not a valid solution."
      io.puts "Expected output:  #{@challenges[challenge_number][1].inspect}"
      io.puts "    Your output:  #{answer.inspect}"
    end && nil
  end

  def solutions
    @solutions.each_with_index do |solution, i|
      io.puts describe_challenge(solution, i, "Solution").
              map { |line| line.sub(/^  /, "\\0\\0") }
      description = "  Solution:  #{solution[3]}(#{solution[4].inspect}"
      unless solution[5].empty?
        description << ", #{solution[5].map { |arg| arg.inspect }.join(', ')}"
      end
      io.puts description + ")"
    end && nil
  end

  def save(file_name = "regexp_challenge.yaml")
    File.open(file_name, "w") { |file| YAML.dump(self, file) }
  end

  private

  def describe_challenge(challenge, number, title = "Challenge")
    description = [ "#{title} ##{number}:",
                    "   Input:  #{challenge[0].inspect}",
                    "  Output:  #{challenge[1].inspect}", ]
    unless challenge[2].nil?
      description << "    Note:  #{challenge[2].inspect}"
    end
    description
  end
end