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raganwald.com
@raganwald.functional.cafe.ap.brid.gy
Reg "raganwald" Braithwaite's account for discussing functional programming and shamelessly plugging essays about programming.

Follows are NOT endorsements. This […]

🌉 bridged from ⁂ https://functional.cafe/@raganwald, follow @ap.brid.gy to interact
JavaScript Allongé was written in this converted semi-detached cottage.
January 16, 2026 at 3:55 PM
Life, coffee, and blueberry pie.

https://conwaylife.com/book/
January 16, 2026 at 2:55 PM
Although many people say that JavaScript Allongé is a book about functional programming, it’s actually a book about how functions as first-class entities facilitate composition.

So... Although Kleisli arrows allow for the composition of functions that work […]

[Original post on functional.cafe]
December 5, 2025 at 2:43 PM
A personal favourite. And yes there *is* a Mister Braithwaite in “Enter the Dragon!”

https://raganwald.com/2011/11/01/williams-master-of-the-comefrom.html
December 3, 2025 at 3:03 AM
At the turn of the century, OG blogger Joel Spolsky posited the "Joel Test," twelve simple yes/no questions that defined a reasonable-by-the-standards-of-the-day local optimum for shipping software. Some seem ridiculously obvious today, but weren't standard […]

[Original post on functional.cafe]
November 24, 2025 at 3:52 PM
November 15, 2025 at 1:59 PM
November 9, 2025 at 2:08 PM
A Brutal Look at Balanced Parentheses, Computing Machines, and Pushdown Automata

https://raganwald.com/2019/02/14/i-love-programming-and-programmers.html
November 8, 2025 at 7:52 PM
Forget algebraic types, the Type Lords use Gallifrean types.
November 8, 2025 at 5:11 PM
There are two ways to write production #typescript. One is to use such advanced type features that if it compiles at all, you can be sure there are no obvious bugs. The other is to write such straightforward, extremely simple types that there are obviously no bugs.

Only a third method works.
November 6, 2025 at 2:29 PM
November 5, 2025 at 3:52 PM
Since 1951.
November 4, 2025 at 7:17 PM
November 3, 2025 at 8:08 PM
JavaScript Allongé follows this pattern:

https://raganwald.com/assets/books/javascriptallongesix.pdf

The very first version was written before ES2015. Its purpose was to discuss programming with first-class functions and composition. To do that, it had to […]

[Original post on functional.cafe]
October 27, 2025 at 3:14 PM
A long time ago, in a ruby-encrusted galaxy far, far away...

https://raganwald.com/assets/books/kestrels-quirky-birds-and-hopeless-egocentricity.pdf
August 13, 2025 at 2:46 PM
My first type-level TypeScript Y Combinator good enough to criticize:

https://gist.github.com/raganwald/6558ddfd76b16fe7b7213a80f54576e0
August 4, 2025 at 4:17 PM
August 4, 2025 at 3:42 PM
A type-level TypeScript implementation of the Mockingbird. The Why Bird and Jackson’s Widowbird are next...
July 30, 2025 at 3:32 PM
“[Structure and Interpretation of Computer Programs] wasn't really about Scheme; I think a lot of the point of using Scheme (as I understood it) is that the language is so minimalist and so beautiful that even this first intro course can be about fundamental […]

[Original post on functional.cafe]
July 26, 2025 at 2:57 PM
The SNOBOL4 Programming Language, also known by its fans as “The Green Book:”

https://raganwald.com/assets/books/snobol-green-book.pdf
July 15, 2025 at 1:52 PM
“...We’re done. And this is a win over the typical recursive or even iterative solution for large numbers, because while each operation is more expensive, we only perform log2n operations.”

—An ES6 function to compute the nth Fibonacci number (2015) […]

[Original post on functional.cafe]
June 23, 2025 at 4:35 PM
In 1972, John Horton Conway invented the FRACTRAN programming language to show that a generalization of the Collatz problem is algorithmically undecidable. He showed that this generalized form is equivalent to FRACTRAN programs, and also that FRACTRAN […]

[Original post on functional.cafe]
June 19, 2025 at 12:55 PM
The SNOBOL4 Programming Language, also known by its fans as, “The Green Book:”

https://raganwald.com/assets/books/snobol-green-book.pdf
June 9, 2025 at 3:21 PM
In 2004, Matthew Cook proved that the Rule 110 elementary cellular automaton is universal. His construction began with the existing proof that Post Tag Systems are universal, then introduced a variation, the Cyclic Tag System, which he showed is equivalent to […]

[Original post on functional.cafe]
June 6, 2025 at 12:49 PM
“DNA does not have one strand for animals, another for cats, and a third for jaguars. It does not compose these specializations together to produce the final specimen individual. DNA is a chaotic, unstructured mess. Einstein once said that “God does not play […]

[Original post on functional.cafe]
May 31, 2025 at 11:31 AM