Boolean Blindness Explained for Beginners in Haskell
summary
Argues that Booleans are an information-poor type and shows concrete fixes in Haskell: replace Boolean flags with pattern matching, custom ADTs or Maybe/Either return types to make functions total, pass decision logic as functions instead of flags, and compose predicates with a fold using the reverse bind to short‑circuit. Examples include a safer list append, turning a partial lookup into a Maybe result, and a scalable validate pipeline; the compiler then prevents the common mistakes described.
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chapters (27)
- 0:00Intro
- 2:38Information Poverty
- 3:35Common Anti-pattern
- 3:57List Append
- 5:36What are the problems?
- 5:52Partial Functions
- 9:11Higher-Kinded Types
- 9:41Maybe as a Return Type
- 11:01Principle
- 12:56Example
- 14:13Solution (Kind Of)
- 14:33Algebraic Data Types
- 17:49Input Validation
- 18:14Replace First Flag
- 18:50Replace Second Flag
- 19:51Maybe as Return Type
- 21:25The Right Section of
- 21:57A Scalable Version
- 22:30Helper Function
- 23:35A Better Helper
- 24:14Let's Use a Monad
- 25:53Reverse Bind for Maybe
- 26:18Using a Monad Instance
- 27:43Data Flow
- 28:57Pretty Cool?
- 29:34Summary
- 35:02First Try At Refactoring
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