Can Lehmann

I like building programming languages and compilers. Currently working on verijit (npub17ww…mwfs)

GitHub: https://github.com/can-lehmann/
Pronouns: he/him

Last Notes

2026-02-20 02:56:50 UTC

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I don't think so, I have done a fair bit of LISP/Scheme things including writing a compiler and then making it self hosting in my youth though. My conclusion from that was that homoiconicity is extremely cool, though in practice taping a macro system to an existing non-homoiconic language solves most problems just as well.
(Just because we are recommending stuff, rn, I think you might enjoy https://www.youtube.com/watch?v=mQnKZr97y7A)

2026-02-20 02:43:11 UTC

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I was actually not aware of META II. On first glance it looks like this is essentially a parser generator that outputs stack machine code along the way? It seems like a spiritual predecessor (though it seems quite different technically) to the crazy partial evaluation techniques we have today.

2026-02-20 02:06:48 UTC

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Generally I would be interested to what extent people have explored "compiler meta theory" yet? Maybe something category theory based?

2026-02-20 01:51:47 UTC

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This ties in with the idea that a compiler is a thing which lowers between abstraction levels. Abstraction levels are "closed" in some sense, i.e. one does not need to know how an abstraction level is implemented physically to execute a program. This also implies that from this perspective abstraction levels are not ordered (unlike we might commonly think, C is not really higher/lower than assembly in this view, as you could lower in both directions)

2026-02-20 01:41:46 UTC

There seems to be some link between compiler construction and emergence in complex systems. Essentially, in compilers, we (ab)use emergence to lower between abstraction levels. Does anyone know any literature that explores this?
#compiler #PLdev

2026-01-02 23:28:36 UTC

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The clock is just a simple loop whose length determines the period. Currently I just hard code the period, but theoretically it should be possible to determine the minimum period from the combinatorial logic depth.
https://files.mastodon.social/media_attachments/files/115/828/096/935/991/820/original/6d68084ad94f82a2.png

2026-01-02 23:27:24 UTC

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Turns out building a d latch from McCulloch-Pitts neurons is also not that hard, so it can actually also translate sequential logic now. This simple counter
reg [3:0] counter = 0;
always @(posedge clock)
counter <= counter + 1;
Results in the following neural network:
https://files.mastodon.social/media_attachments/files/115/828/085/789/725/672/original/b5158d042b1662be.png

2026-01-02 22:21:57 UTC

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It only does combinatorial logic, so it is not (yet) possible to convert a processor into a McCulloch-Pitts Neural Networks.

2026-01-02 22:20:29 UTC

@npub1z8r…mrq6 Seems like you have (unintentionally) nerd-sniped me into building a Verilog to McCulloch-Pitts Neural Networks flow...
https://github.com/can-lehmann/verilog2neur

2026-01-02 19:57:19 UTC

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I imagine using it for music is a bit harder though, since you need to get the wire lengths exactly right for the timing to work out.

2026-01-02 19:54:30 UTC

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Yeah, I think I first saw it because someone actually made a Minetest/Luanti mod using wireworld as a redstone replacement. Never played around with the mod, but I still think it was a neat idea 😃

2026-01-02 19:48:28 UTC

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Sadly unable to find it right now, but I seem to remember some tool where you can layout rhythms by drawing cycles on a 2 dimensional grid. A "program counter" travels along the cycles playing any placed sounds it encounters. This means that the length of the cycle is the duration of a loop. It seems like it might end up feeling similar to that. While the actual positioning is of course irrelevant with neurons, you would probably end up building similar cycles which trigger sounds.

2026-01-02 19:35:18 UTC

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Has anyone built a music livecoding tool based on this yet? (I assume that's where your kickdrum example is going)

2025-12-13 20:55:17 UTC

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(well, ok, maybe the reasoning is more in the other direction. I am working on metajit.cpp for a research project and thought it might also be a good fit for writing a UXN jit).

2025-12-13 20:53:56 UTC

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That's why I decided to not write the JIT by hand 😉

2025-12-13 20:16:55 UTC

👀 I am currently recovering from an illness and decided it might be a fun idea to develop a just in time compiler for UXN while I wait for my health to improve. Decided it might be fun to post some updates along the way: https://github.com/can-lehmann/uxnjit