Hacker News: leontrolski

New comment by leontrolski in "Pgtestdb's template cloning approach to testing is fast"

leontrolski — Sat, 01 Aug 2026 18:23:33 +0000

Agreed, benchmarking, I only see a slight speedup on MacOS - https://github.com/leontrolski/postgresql-testing#:~:text=ra...

New comment by leontrolski in "Pgtestdb's template cloning approach to testing is fast"

leontrolski — Sat, 01 Aug 2026 18:21:55 +0000

Being to lazy to think or test it - does the above reset SEQUENCEs?

New comment by leontrolski in "Pgtestdb's template cloning approach to testing is fast"

leontrolski — Sat, 01 Aug 2026 18:20:49 +0000

I concur with this approach. TRANSACTION-y tests (the default in Django) often don't quite line up with reality and make it hard to eg. drop in a breakpoint and run a server against the test's db state.

I've experimented (see below) with TEMPLATE dbs and such in Python (with inspiration from this library). IMHO the "around 100ms" mark is pretty slow for a big test suite. Interestingly, pg_restore is only twice as slow as TEMPLATEs.

https://github.com/leontrolski/postgresql-testing

I'd be interested about how all this compares to snapshotting the postrgres dir with ZFS and restoring to that, but don't have a Linux box to hand.

New comment by leontrolski in "Pip install Postgres – no Docker/Brew/apt"

leontrolski — Thu, 23 Jul 2026 21:19:39 +0000

Some discussion on (ab?)using pypi to distribute binaries - https://discuss.python.org/t/use-of-pypi-as-a-generic-storag...

Pip install Postgres – no Docker/Brew/apt

leontrolski — Thu, 23 Jul 2026 21:17:34 +0000

Article URL: https://github.com/leontrolski/postgresql-testing

Comments URL: https://news.ycombinator.com/item?id=49028169

Points: 29

# Comments: 8

Prism: An Impure Functional Language with Typed Effects

leontrolski — Sun, 28 Jun 2026 08:48:34 +0000

Article URL: https://www.stephendiehl.com/posts/prism/

Comments URL: https://news.ycombinator.com/item?id=48705562

Points: 6

# Comments: 0

New comment by leontrolski in "(How to Write a (Lisp) Interpreter (In Python)) (2010)"

leontrolski — Mon, 22 Jun 2026 06:25:34 +0000

Similarly - 80 line LISP interpreter with integers, lexical scope, first class functions

https://leontrolski.github.io/interpreter.html

New comment by leontrolski in "All of human cooking compressed into 2 megabytes"

leontrolski — Wed, 27 May 2026 12:10:14 +0000

Neat.

I'm trying to compress recipes into little schematics https://leontrolski.github.io/recipes.html

New comment by leontrolski in "Generalised plusequals"

leontrolski — Sat, 25 Apr 2026 08:55:08 +0000

What would be the equivalent to this in Haskell (with or without lens):

    cat = Cat(age=3)
    l = [1, [2, cat], 4]
    alt l[1][1].age.=9

That would give us l equal to:

    [1, [2, Cat(age=9)], 4]

New comment by leontrolski in "Generalised plusequals"

leontrolski — Sat, 25 Apr 2026 08:41:13 +0000

This is surprising to me:

  l[1][1].age:9
  # (1,(2,{"age":9}),4)

How come it doesn't return just:

  {"age":9}

Or is there something totally different going on with references here? As in, how is this different to:

  l_inner = l[1][1]
  l_inner.age:9

Generalised plusequals

leontrolski — Fri, 24 Apr 2026 21:34:25 +0000

Article URL: https://leontrolski.github.io/alt.html

Comments URL: https://news.ycombinator.com/item?id=47896086

Points: 16

# Comments: 11

“Disregard That” Attacks

leontrolski — Wed, 25 Mar 2026 23:11:34 +0000

Article URL: https://calpaterson.com/disregard.html

Comments URL: https://news.ycombinator.com/item?id=47524519

Points: 129

# Comments: 94

New comment by leontrolski in "Is anybody else bored of talking about AI?"

leontrolski — Tue, 24 Mar 2026 21:58:54 +0000

Yes, AI or no AI, tell me about something actually interesting that you're working on.

Currently it feels a bit like everyone is talking about what new editor they're using. I don't care about that type of developer tooling very much. AI isn't coming up with some exciting new database, type system, etc etc.

"Look at how I'm able to web dev x% faster" because of LLMs is boring.

Aldo's Game of Music

leontrolski — Wed, 04 Mar 2026 22:34:28 +0000

Article URL: https://www.aldodevos.nl/game_of_music/

Comments URL: https://news.ycombinator.com/item?id=47254933

Points: 1

# Comments: 0

National Raisin Reserve

leontrolski — Sun, 28 Dec 2025 09:30:37 +0000

Article URL: https://en.wikipedia.org/wiki/National_Raisin_Reserve

Comments URL: https://news.ycombinator.com/item?id=46409705

Points: 6

# Comments: 0

Show HN: I 3D printed a running buggy

leontrolski — Mon, 17 Nov 2025 20:57:29 +0000

Article URL: https://leontrolski.github.io/buggy.html

Comments URL: https://news.ycombinator.com/item?id=45958194

Points: 1

# Comments: 0

New comment by leontrolski in "Venn Diagram for 7 Sets"

leontrolski — Sat, 08 Nov 2025 11:13:52 +0000

Ditto, another Upset blog post - https://leontrolski.github.io/upset.html

Using Python 3.14 template strings to write Python

leontrolski — Tue, 07 Oct 2025 20:30:28 +0000

Article URL: https://leontrolski.github.io/trolskgen.html

Comments URL: https://news.ycombinator.com/item?id=45508428

Points: 3

# Comments: 1

New comment by leontrolski in "A Early History of Algebraic Data Types"

leontrolski — Thu, 25 Sep 2025 19:18:32 +0000

Lovely writeup!

> Pascal did not have sum types because Wirth thought they were less flexible than untagged unions

I'm not sure whether my dream language would have tagged or untagged unions (Scala 3 has both it seems). I'd be interested if anyone has any further points of comparison beyond:

Tagged unions, eg. in Rust: enum Tagged {A(i64), B(String), C(f64)} Untagged unions, eg. in typed Python: Tagged = int | str | float

Tagged unions are better as you can represent duplicated types and types with no data, eg: enum Tagged {A, B(f64), C(f64)}

Untagged unions are better as you can willy nilly create new subsets and intersections of types. I find often in AST-ish work I want to express eg: def f(x: A | B | C) -> A | B

New comment by leontrolski in "Do not download the app, use the website"

leontrolski — Sat, 26 Jul 2025 09:03:01 +0000

A reminder of all the features available right now with PWAs - https://whatpwacando.today