finally made a breakthrough in parens-8 v5. I can now compile early returns and arbitrary control flow within a stack frame. the key was realizing that things like early returns only really make sense in the context of *statements*, not expressions. the solution was then to compile statements separately from expressions, and give them a static continuation to manipulate.
Miss Mouse
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rodents, #pico8 tinkerer, software researcher
@johanpeitz @winduptoy I got it to run on Linux (without wine) by extracting the source from the executable and building my own copy of gifcatlib.
@Ronflaix not what I was hoping for, but TIL that C++20 added an overload for std::visit that lets you specify the return type, which allows for this kind of thing:
@Ronflaix wait, what does the full line look like?
@Ronflaix yeah, it's super useful for turning lambdas into function pointers: `auto* ptr = +[](void* p){ use(p); };`
@zep playing around with `ud:take`, there seems to be a bug when using spans longer than 1: the last row will only have the first column populated.
repro:
function chunk(ud, x, y, w, h)
local s = ud:width()
local rows = userdata("i32", h)
h -= 1
rows:set(0, y*s+x)
rows:set(h, (y+h)*s+x)
return ud:take(rows:lerp(), nil, 0, 0, w)
end
function iota(n)
if (n > 0) return n, iota(n-1)
end
local data = vec(iota(8*8))
data:mutate("f64", 8, 8)
?pod(data)
?pod(chunk(data, 1, 2, 4, 3))
keep thinking about what a post mortem article should look like and at this point idfk. two months ago I knew exactly what to put in there to explain the journey that happened over the last couple years. now it all feels like a joke.
something that keeps happening when working on parens-8 is that I'll figure out a clever way to make my vm/compiler combo more effective, get really proud-snarky about it, and then find out later that it's something people already figured out a few decades ago.
the latest instance of that was the idea of using CPS at the compiler level instead of the vm level, which happens to be what "compiling with continuations" is about. I'm not sure how to feel about that. validation? frustration? I guess I wish I could work in that specific field of software full time instead of stumbling across this kind of thing in the dark.
working on the crescent (subset of lua) compiler for parens-8, I got so frustrated with string parsing that I started looking into writing an llvm backend as a joke, or so I thought.
turns out, v5's vm is similar enough to wasm that basing my hypothetical parens-8 llvm backend on wasm's is concerningly feasible.