Is Maybe an Option? How to Model Nothing
summary
Null causes ambiguous states, so the code replaces it with Option/Maybe for parseWetsuitSize and repository returns, and introduces a Result type for errors; concrete scuba-diving examples show a registration return type implemented as a sum type with cases Accepted(confirmationNumber), CourseFull and WaitingList. Examples use F# and C#-style patterns; the compiler forces handling of none/ok cases and algebraic data types make illegal states unrepresentable, preventing runtime null checks and reducing domain bugs.
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chapters (9)
- 0:00Introduction to modeling
- 1:36The problem with null
- 4:50Dealing with uncertainty
- 7:11Using the option type
- 11:02Error handling with results
- 13:51Limitations of options
- 17:23Algebraic data types
- 19:15Unrepresentable states
- 20:27Conclusion and takeaways
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