A “weeknote”, I am told is not like a blog post, and yet here I am putting this first one on my blog. I am sovereign of my domain name, I shall do as I see fit. Expect: bullet-journal style reflections. Also I think these are usually supposed to be a Friday sort of thing, but here I am writing one on a Thursday. It’s a really Friday-feeling Thursday, in my defense.

• Somehow I signed myself up for a bit more than usual this week.
• Today I gave a little 5-minute talk on my seamstress program for the first time.
• More about it later, but the preparation for it somehow managed to be a bit of a Hail Mary moment
• On Saturday, I’m performing a set of live-coded music at Wonderville, here in NYC.
• Don’t tell anyone (lol) but I really need to buckle down and rehearse.
• Somehow I decided that I wanted to add unit tests to seamstress over the weekend.
• They’ve been really helpful so far!
• Seamstress is kind of annoying to test from Zig:
• All the “real action” (by design) happens in the Lua layer, and calling into Lua from Zig gets mind-bendy and verbose quite quickly.
• Additionally, (again, by design) there isn’t a ton of heavy business logic happening in Zig?
• Like, I ran into some endian-ness surprises when parsing hex numbers as RGB colors, but that’s about it
• But from Lua’s perspective, since the Zig event loop and Lua VM are all set up, there’s plenty to test
• Anyway, all of this is to say I’m using Busted, a Lua testing framework
• But I quickly discovered that Busted tests have no builtin support for asynchronicity
• This is an issue for testing the actual operation of seamstress 2, because idiomatic (lol) seamstress code makes use of several provided callbacks
• So what’s a Rylee to do?
• I ended up hand-rolling a Promise type and async / await functionality heavily inspired by JavaScript.
• Here it is in action

  -- calling Promise creates a Promise type
  p = seamstress.async.Promise(function()
    print('hello from the promise')
  end)
  print(p)
  -- output:
  -- seamstress.tui.Promise 0x[some address]
  -- 'hello from the promise'

  -- calling async creates a function which returns a Promise
  f = seamstress.async(function(x, y)
    return x + y
  end)

  -- we can either chain the Promise with `anon`
  -- (`then` is a reserved word in Lua)
  -- or when in an async context, we may `await` it
  f(5, 4):anon(function(x) print('we got ' .. x .. ' folks!') end)
  -- output:
  -- we got 9 folks!

  g = seamstress.async.Promise(function()
    local z = f(13 ,3):await()
    print('we got ' .. z .. ' this time folks!')
  end)
  -- output:
  -- we got 16 this time folks!

• the implementation was truly brain-breaking and yet ultimately very simple code to write:
• under the hood, a Promise executing Lua code puts a short timer onto the Zig event loop. This timer resumes execution of the Lua function until it’s finished.
• Awaiting a Promise is as simple as yielding until that Promise is resolved, and then reaching into its stack and grabbing the values.
• Many thanks to Jeremy Kaplan and Kyle Edwards for talking me through the gnarly bits.
• Anyway, getting that right somehow ate most of the early part of my week.
• Glad it did, but I might have been less stressed today if I had, y’know, not wanted so badly to get that working.
• Oh I made a little minesweeper demo game in seamstress 2.
• It runs in the terminal; the whole code for the game is 236 lines of code, which feels like a reasonable, small number.