ugly proof of concept for implementing strict, keyword based union types following the ideas from F#

[andrzejsliwa]

# Proof of concept for modeling Business Domain with Nil/Null or Optional based on F# union types
#
# type RegistrationFlow =
#   | Accepted of confirmation_number: int
#   | CourseFull
#   | WaitingList if spot: int
#
# Example contract of method which depends on this type:
#
# let registerForCourse (course: Course) : RegistrationFlow = ...

class RegistrationFlow
  Accepted = data :confirmation_number, :full_name
  CourseFull = data
  WaitingList = data :spot
end