turingmachine-to-dot.rb

a = <<EOS
  0        _       _       R       0
  0        1       1       R       1
  1        _       1       R       2
  1        1       1       R       1
  2        _       _       L       3
  2        1       1       R       2
  3        _       _       L       3
  3        1       _       L       4
  4        _       _       R       stop
  4        1       1       L       4
EOS

b = a.lines.map{|x|
  m = x.match(/(\S+) +(\S+) +(\S+) +(\S+) +(\S+)/)
  m.to_a[1..-1]
}

states = (b.map{|x| x[0] } + b.map{|x| x[4] }).uniq

puts "digraph sample {"
puts "graph [rankdir = LR];"

states.each do |s|
  puts "_#{s} [label=\"#{s}\"];"
end


b.each do |m|
  q1, s1, s2, ac, q2 = m
  puts "_#{q1} -> _#{q2} [label = \"#{s1} #{s2} #{ac}\"];"
end
puts "}"