function_composition.rb

# the return of the one, is the param of the next
one = ->(value) { puts "received #{value}"; 1 }
two = ->(value) { puts "received #{value}"; 2 }
three = ->(value) { puts "received #{value}"; 3 }
done = one >> two >> three
puts "-" * 10
puts "finalizing #{done.call("calling")}"
puts "-" * 10

# for example...
apply_discount = ->(price) {
  price - (price * 0.1)
}

apply_coupon = -> (price) {
  price - (price * 0.1)
}

apply_taxes = ->(price) {
  price + (price * 0.06)
}

notify = -> (price) {
  puts "omg! so notified #{price}"
  price
}

discount = apply_taxes >> apply_discount
puts "discount #{discount.call 100}"
puts "-" * 10

coupon = apply_taxes >> apply_coupon
puts "coupon #{coupon.call 100}"
puts "-" * 10

mega_discout = apply_taxes >> apply_coupon >> apply_discount
puts "mega_discount #{mega_discout.call 100}"
puts "-" * 10

discount_and_notify = discount >> notify
puts "discount and notify #{discount_and_notify.call 100}"
puts "-" * 10

reveeerse = apply_taxes << notify
puts "reveeerse #{reveeerse.call 100}"
puts "-" * 10

### for a more down to earth
# get(url) >> extract_price >> apply_discount >> ...