closures.rb

# My final solution to 'Closures' exercise at the
# Scottish Ruby Conference - Ruby Tutorial
# by Chad Fowler and Keavy McMinn.

# The returning keyword/proc is not defined in Ruby 1.8. Define it here
#
def returning(value, &block)
  yield
  value
end


# Use returning to remembering and returning the value
# of start before modifying it.
#
def counter(start, inc)
  lambda { returning(start) { start += inc } }
end

result = counter(10, 2)

puts result.call
puts result.call
puts result.call
puts result.call

result = counter(2, 3)

puts result.call
puts result.call
puts result.call
puts result.call