4 ms·

Recommended path to read the Lua source code by the author of LuaJIT (2007)

89 points by jxub 8y ago

akavel 8y ago
(2007)
- ufo 8y ago
  His reading order is still good advice today though. Lua has seen many improvements recently but the file organization is unchanged. (I can confirm this because I need to frequently dive into that codebase as part of my job)
  - akavel 8y ago
    Yeah, all o-kay; my comment was not meant as a dismissal but rather as a clarification. Because of various social and soap-opera-like-drama reasons in the community, I was super surprised and electrified to see such content assuming by default it was recent news (2018), given it was unmarked. Once I realized it was from 2007, as much as love the content itself, it became mostly not-news for me, and I cannot deny feeling to some extent misled by this omission.
    - ufo 8y ago
      Absolutely. I just wanted to point out the advice itself wasnt outdated.
      - akavel 8y ago
        :)
- sctb 8y ago
  Added, thanks!
jdonaldson 8y ago
Really hope we hear more from Mike Pall this year. He's been off the radar for way too long.
oddity 8y ago
Lua really is a fantastic example of how to design and write an interpreter. The style and details can be debated, but the high-level design is expertly crafted and something I wish more interpreters would take inspiration from. I dislike the language, but the combination of its well-designed interpreter(s) and the general fat-free language design makes it the least shit of the popular scripting languages in my eyes. luajit is also a very well designed JIT compiler, but I wouldn't recommend it for beginners because of how dense it is. Understanding luajit is comparable to understanding something out of the demoscene because of how much gets squeezed out of every line of code.
- TheAceOfHearts 8y ago
  Do you have any suggestions for someone that doesn't know much about the subject but would be interested in learning more about it? Long-term I'd like to be able to dive into stuff like V8 and actually understand its internals.
  - ufo 8y ago
    Mike pall wrote some posts in various mailing lists over the years that explain some of the things he did (but be aware that they only really scratch the surface) https://news.ycombinator.com/item?id=11322060 https://news.ycombinator.com/item?id=11322060 https://news.ycombinator.com/item?id=2588696 https://news.ycombinator.com/item?id=2588696 http://lambda-the-ultimate.org/node/3851 http://lambda-the-ultimate.org/node/3851 The thing that makes luajit hard to understand is a combination of two things. First, the jit compiler uses advanced techniques that aren't easy to learn just looking at the code. You really need to know a lot of compiler theory to just get started. Additionally, mike pall wrote a large chunk of luajit in assembly language and hand-optimized lots of things, which gives the code that dense demoscene feeling that was mentioned before. If you want to learn more about luajit one crucial thing would be learning about tracing jits for dynamic languages (luajit goes all in on tracing jit). The wikipedia article is pretty good. For papers make sure you read "Trace-based Just-in-Time Type Specialization for Dynamic Languages" https://en.wikipedia.org/wiki/Tracing_just-in-time_compilation https://en.wikipedia.org/wiki/Tracing_just-in-time_compilati... If you want to dive into a jit codebase one that might be interesting is the Higgs JIT. I haven't looked at the code itself very closely but I read Maxine's PhD thesis and her presentations on jit and I liked her approach of trying to make a jit that is as simple as possible. Most jits these days are massively complex beasts. https://pointersgonewild.com/higgs/ https://pointersgonewild.com/higgs/

89 points by jxub 8y ago

akavel 8y ago

(2007)

ufo 8y ago
His reading order is still good advice today though. Lua has seen many improvements recently but the file organization is unchanged. (I can confirm this because I need to frequently dive into that codebase as part of my job)
- akavel 8y ago
  Yeah, all o-kay; my comment was not meant as a dismissal but rather as a clarification. Because of various social and soap-opera-like-drama reasons in the community, I was super surprised and electrified to see such content assuming by default it was recent news (2018), given it was unmarked. Once I realized it was from 2007, as much as love the content itself, it became mostly not-news for me, and I cannot deny feeling to some extent misled by this omission.
  - ufo 8y ago
    Absolutely. I just wanted to point out the advice itself wasnt outdated.
    - akavel 8y ago
      :)
sctb 8y ago
Added, thanks!

jdonaldson 8y ago

Really hope we hear more from Mike Pall this year. He's been off the radar for way too long.

oddity 8y ago

Lua really is a fantastic example of how to design and write an interpreter. The style and details can be debated, but the high-level design is expertly crafted and something I wish more interpreters would take inspiration from. I dislike the language, but the combination of its well-designed interpreter(s) and the general fat-free language design makes it the least shit of the popular scripting languages in my eyes. luajit is also a very well designed JIT compiler, but I wouldn't recommend it for beginners because of how dense it is. Understanding luajit is comparable to understanding something out of the demoscene because of how much gets squeezed out of every line of code.

TheAceOfHearts 8y ago
Do you have any suggestions for someone that doesn't know much about the subject but would be interested in learning more about it? Long-term I'd like to be able to dive into stuff like V8 and actually understand its internals.
- ufo 8y ago
  Mike pall wrote some posts in various mailing lists over the years that explain some of the things he did (but be aware that they only really scratch the surface) https://news.ycombinator.com/item?id=11322060 https://news.ycombinator.com/item?id=11322060 https://news.ycombinator.com/item?id=2588696 https://news.ycombinator.com/item?id=2588696 http://lambda-the-ultimate.org/node/3851 http://lambda-the-ultimate.org/node/3851 The thing that makes luajit hard to understand is a combination of two things. First, the jit compiler uses advanced techniques that aren't easy to learn just looking at the code. You really need to know a lot of compiler theory to just get started. Additionally, mike pall wrote a large chunk of luajit in assembly language and hand-optimized lots of things, which gives the code that dense demoscene feeling that was mentioned before. If you want to learn more about luajit one crucial thing would be learning about tracing jits for dynamic languages (luajit goes all in on tracing jit). The wikipedia article is pretty good. For papers make sure you read "Trace-based Just-in-Time Type Specialization for Dynamic Languages" https://en.wikipedia.org/wiki/Tracing_just-in-time_compilation https://en.wikipedia.org/wiki/Tracing_just-in-time_compilati... If you want to dive into a jit codebase one that might be interesting is the Higgs JIT. I haven't looked at the code itself very closely but I read Maxine's PhD thesis and her presentations on jit and I liked her approach of trying to make a jit that is as simple as possible. Most jits these days are massively complex beasts. https://pointersgonewild.com/higgs/ https://pointersgonewild.com/higgs/