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   mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

   If you look close at that sample, you may notice the thing that distinguishes this lisp from other lisps, and the idea I wanted to play with that had me writing this in the first place: There are no functions in this LISP. Or rather there is no distinction between lists and functions. You put a list as the first item of an execution list, it just interprets it as a list of lines of LISP and executes them one by one. I was trying to make "TCL but LISP" and this is what I thought that would mean

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     I've been writing all my new language's test code prepped to work with the regression test runner script I used with Emily and Emily2. I didn't actually have the test script itself in because I had to fuss with it a bit to teach it to run cargo before invoking the interpreter (so that the interpreter exists). Ran it and…

     5 tests failed of 13.

     That's good!!! That's extremely good!!!

     Because that first failure? quote.ls0?

     Looked at it. That's a real bug!!

     The test runner found a bug ALREADY!

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     It's useless to anyone but me, but I am so proud of this little script.

     https://github.com/mcclure/emily/blob/stable/develop/regression.py 2014 version— 217 lines

     https://github.com/mcclure/bitbucket-backup/blob/archive/repos/emily-python/contents/develop/regression.py 2017 version-- 466 lines

     https://github.com/mcclure/lisp0-experiment/blob/unstable/tools/regression.py 2024 version-- 450 lines

     It's not "portable". I have to rewrite it a bit every new project I port it into. It's simple and it's adaptable and it does *exactly* what I need.

     My "Test cases" are a few dozen programs with embedded comments explaining what STDOUT should be seen when they're run.

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     Yesterday I wrote a copying garbage collector in 52 lines of code and in about an hour. It was I was *so* happy and satisfied and the code was so clean and elegant. Then I realized the way I had done it was incompatible with the Rust borrow checker and spent another hour or two trying to figure out how to work around it. The Rust Experience.

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     Today I fixed it and now I have a 62 line GC (7 lines whitespace/comments) which is *slightly* less efficient than it could be due to every object being temporarily copied to a temporary heap object before the new space.

     The original design *could* be made to work if I write my own implementation of Vec, which would be easy but annoying. The problem is I need to push to the end of a Vec while a mutable ref is held to one of its members, which *is* Rust invariant-safe, but not borrow-check-legal

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     I do suspect I am going to write many more than 62 lines of code trying to *test* this.

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     Update: I wrote the tests, and it actually doesn't work. But I know why.

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     Can't sleep. Distracting thunderstorms. Stomach's angry.

     Only one thing to do: Stay up and learn to write a Drop implementation

     (I think this is probably pretty simple, it's just one of a few relatively basic Rust things I haven't yet turned out to have a need for)

     Yes that's right I'm implementing OBJECT POOLING

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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     Okay the garbage collector now "works"! In the sense that it can remove garbage from the system. (The problem before was I have a list of roots which includes any item the VM is currently operating on,, and roots were… never… getting removed… from the root list.)

     It still does *not* work, in the sense that after the collection every pointer in the system is pointing to the wrong object. Oops!

     GreenSkyOverMe (Monika) repeated this.
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     mcc (mcc@mastodon.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST mcc

     in reply to

     So I added some debug prints to the GC and upon looking at the outputs I *immediately*, intuitively understood what was wrong and how to fix it (you'll be unsurprised to learn it was an off-by-one error… every pointer was being updated to its correct new value minus one).

     I made the fix. I reran the test.

     It failed in the exact same way.

     ¯\_(ツ)_/¯

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     GreenSkyOverMe (Monika) (greenskyoverme@ohai.social)'s status on Thursday, 03-Apr-2025 16:01:14 JST GreenSkyOverMe (Monika)

     in reply to

     @mcc 🙀