Maybe Not - Rich Hickey
What it is
Rich Hickey's Clojure/Conj 2018 keynote argues that Maybe/Option types and rigid type signatures are a poor way to model data that changes over time. He builds the case around optionality, schema growth and compatibility, and presents the ideas behind Clojure spec as an alternative.
Why Hacker News recommends it
HN commenters send people to it whenever nulls, Maybe/Option or static typing come up, as a thoughtful dissent from the type-system orthodoxy that changes how some people model data.
- 14 people recommended it
- 11 different months
- 5 strong recommendations
- first 2018, last 2025
What HN commenters said
“rich hickey just changed how I think about domain modelling forever with this talk”
Hickey talk that changed how the commenter thinks about domain modelling
slifin, 2018-11 · Strong recommendation · in “Clojure REBL [video]”
“Rich Hickey's "Maybe Not" should be watched by anyone who thinks nulls/nils/undefineds are okay.”
Critique of nulls and Optional/Maybe types
gambler, 2018-12 · Strong recommendation · in “NULL: The worst mistake of computer science? (2015)”
“Another excellent talk by the creator of Clojure, and like the previous ones, relevant for all programmers.”
Excellent talk relevant to all programmers
ttiurani, 2018-12 · Strong recommendation · in “Ask HN: Best talks of 2018?”
“The ability to spec out the shape of an object, and then in the different contexts in which you need some of that data, specify what you need, is an awesome solution to optionality (Watch the talk!).”
Hickey's spec approach to optionality and data shape
vga805, 2019-01 · Strong recommendation · in “Porting 30K lines of code from Flow to TypeScript”
“My mind blown experience was listening to a Rich Hickey talk (maybe not [1]) that flipped upside down my accepted method of thinking about types”
Flipped the commenter's thinking about types and Either
MarkMarine, 2024-11 · Strong recommendation · in “Programming languages that blew my mind (2023)”
“Any other must watches?”
Listed among must-watch Conj talks
jpittis, 2018-12 · Recommendation · in “Party REPL – A multi-player REPL built for pair-programming [video]”
“I recommend Rich Hickey's talk from about a week ago, called "Maybe Not”
Specifying data shape and a discussion of problems with Maybe types
draw_down, 2018-12 · Recommendation · in “NULL: The worst mistake of computer science? (2015)”
“Maybe check out the talks below and see if they don't enRich you as software engineer.”
Part of a set of Hickey talks to enrich engineers
jmiskovic, 2020-03 · Recommendation · in “Clojure: A Lisp that wants to spread”
Excerpts from Hacker News comments, linked to the originals. Summaries and labels were written by a language model from those comments.
Topics: rich hickey, clojure, maybe types, null, spec, static typing
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