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> webserver (nginx) How timely! Right now I'm learning Lapis [1] by building a toy CRUD app that I plan on deploying to fly.io. Lua reminds me of Go insofar as

> webserver (nginx) How timely! Right now I'm learning Lapis [1] by building a toy CRUD app that I plan on deploying to fly.io. Lua reminds me of Go insofar as it's a really "dumb" language. You can't get too cute and there are a few powerful abstractions that let you accomplish a lot. Coming from Python (which is an endless horizon of PEPs and build artifact standards and name mangling and kwargs and... well, you get the idea) it's kind of a breath of fresh air. As for 1-based indexing: it makes more sense. We're all just used to 0-based because that's how C worked. If you stop and think about it early C was really just a veneer on top of assembly and since addressing an array in memory meant having a pointer to the first element that meant that it was arr[0]. We have no need for this decades later. [1] https://leafo.net/lapis/ https://leafo.net/lapis/

fanf2 3y ago
Years ago I wrote a DNS-over-HTTPS proxy as an nginx / OpenResty module in Lua. The Lua code included a very stripped-down DNS message parser. The 1-based indexes and closed (instead of half-open) intervals were a massive pain in the arse. The code has a tricky mixture of odd and even offsets that would all have been even in C, and it would have been much easier to replace the magic numbers with named constants. https://github.com/fanf2/doh101/blob/master/roles/doh101/files/doh.lua https://github.com/fanf2/doh101/blob/master/roles/doh101/fil...
vvanders 3y ago
Oh you can totally get too cute with metatables. I've seen inheritance/straight-OO(Java/C++ style), component based design, and eventing/message based approaches all with the core primitives that Lua provides. I think my favorite one was one that used yield[1] with the parameters being the number of frames to resume the execution of the coroutine. That was used by a number of our game designers to write AI scripting that felt close to literate programming(I.E. "move x, look for player, yield 30, if found player, go here, etc). You could build a whole AI state machine that fit into one page of code and was very easy to follow. [1] https://www.lua.org/manual/5.1/manual.html#pdf-coroutine.yield https://www.lua.org/manual/5.1/manual.html#pdf-coroutine.yie...

fanf2 3y ago

Years ago I wrote a DNS-over-HTTPS proxy as an nginx / OpenResty module in Lua. The Lua code included a very stripped-down DNS message parser. The 1-based indexes and closed (instead of half-open) intervals were a massive pain in the arse. The code has a tricky mixture of odd and even offsets that would all have been even in C, and it would have been much easier to replace the magic numbers with named constants. https://github.com/fanf2/doh101/blob/master/roles/doh101/files/doh.lua https://github.com/fanf2/doh101/blob/master/roles/doh101/fil...

vvanders 3y ago

Oh you can totally get too cute with metatables. I've seen inheritance/straight-OO(Java/C++ style), component based design, and eventing/message based approaches all with the core primitives that Lua provides. I think my favorite one was one that used yield[1] with the parameters being the number of frames to resume the execution of the coroutine. That was used by a number of our game designers to write AI scripting that felt close to literate programming(I.E. "move x, look for player, yield 30, if found player, go here, etc). You could build a whole AI state machine that fit into one page of code and was very easy to follow. [1] https://www.lua.org/manual/5.1/manual.html#pdf-coroutine.yield https://www.lua.org/manual/5.1/manual.html#pdf-coroutine.yie...