RosettaCodeData/Task/Mad-Libs/Ruby/mad-libs.rb

puts "Enter a story, terminated by an empty line:"
story = ""
until (line = gets).chomp.empty?
  story << line
end

story.scan(/(?<=[<]).+?(?=[>])/).uniq.each do |var|
  print "Enter a value for '#{var}': "
  story.gsub!(/<#{var}>/, gets.chomp)
end

puts
puts story