require 'sloop'

Account = sloop {
  self.balance = 0

  def_deposit  { |v| self.balance += v }
  def_withdraw { |v| self.balance -= v }

  def_inspect { "#(an account with $#{balance})" }
}

my_account = Account.clone

puts my_account.inspect
my_account.deposit 1000
puts my_account.inspect
puts



require 'spawn'

adder = spawn {
  sum = 0
  loop {
    recieve { |sender, msg, *args|
      case msg
      when :add     then sum += args.first
      when :result  then sender.reply sum
      end
    }
  }
}

10.times {
  spawn { |process| adder.send :add, rand(10) }
}

p adder.syncmsg(:result)
puts



require 'solve'

def parent?(a, b)
  Solve.forany({"David" => "John",
                 "Jim" => "David",
                 "Steve" => "Jim",
                 "Nathan" => "Steve"}) do |child, father|
    (a == child) & (b == father)
  end
end

def parent?(a, b)
  ((a == "David")  & (b == "John"))  |
  ((a == "Jim")    & (b == "David")) |
  ((a == "Steve")  & (b == "Jim"))   |
  ((a == "Nathan") & (b == "Steve"))
end

def anchestor?(a, b)
  z = Solve::Variable.new
  parent?(a, b) | parent?(a, z) & Then.do { anchestor?(z, b) }
end

child = Solve::Variable.new(:child)
anchestor = Solve::Variable.new(:anchestor)

solve((child == "Nathan") & anchestor?(child, anchestor)) { |r| p r }