One of the new features I found interesting, declarations for global variables, is buried in the reference manual. Here's a link to the section that discusses it: https://www.lua.org/manual/5.5/manual.html#2.2
I feel like Lua is absolutely underrated. I just wish one of the mainstream browsers actually puts their foot down and starts supporting Lua as scripting language.
Ypu could probably run it in wasm. Of course, without access to the DOM it won't go any further than anything else on wasm. The whole thing is nuts if you ask me. So much lost potential.
ConTeXt has been using beta versions Lua 5.5 for a few years now, so you can look through its source [0] or try running it [1] if you're curious what a large codebase written in Lua 5.5 looks like.
Seems like an odd change, I wonder what the rationale is. Just making it clear to people new to the language that you can't adjust it mid-loop to change the loop count I guess?
In previous versions, you could change it mid-loop. This apparently caused some unintuitive behavior when paired with generators (e.g. `for k, v in pairs(table)`).
I haven't run into this myself, but it does make sense, and eliminating this footgun sounds like a good idea.
Cannot wait for another version of Lua to sit unused basically everywhere.
Truly is a shame, everything seems to have settled on 5.1 for the most part without ever being updated, or any intention of it being updated. Some really nice features post 5.1
I understand each version of Lua introduces breaking changes in the language, which isn't great as the language becomes fragmented (Or not really, once again 5.1 is pretty ubiquitous)
The real reason everyone settled on Lua 5.1 is because that's the version LuaJIT is compatible with, and most people are unwilling to give up the performance gains.
5.1 (by way of LuaJIT) gets a lot of use, but to suggests no one uses the modern versions is just not true. Lua being an embedded language just takes the pressure away to upgrade. It's a feature, not a bug.
1. The luajit documentation basically just had a list of features. AFAIK there isn't any documentation that combines the 5.1 reference with luajit extensions (including things that were backported)
2. In some cases, for example Neovim, luajit extensions aren't guaranteed to be available. It just says there will be a lua runtime compatible with 5.1. Which means a truly portable neovim plugin can't use those extensions
3. There are features from later lua versions I would like to have (in particular <const> and <close>) that will probably never get backported.
4. Some features require luajit to be built with special flags
I never coded in Lua but I found out recently that Lua is now in FreeBSD base [0]
This is huge for Lua and FreeBSD.
Now something that worry me is whenever you need to make an HTTP request or parse some JSON you need to go on a quest for a "library" on the Internet. It doesn't seems to have a (semi-)official "Extended Standard Library" I can quickly trust.
The Lua ecosystem is more like the Lisp ecosystem than Python. The language is small enough that there’s a lot of stuff out there that’s just… finished. Hasn’t been updated in 10 years but still works. The LunarModules org tries to gather it up and keep it compatible.
Lua is really designed as an extension language but it’s such a nifty little language that sometimes you really wish you could use it in place of Python or Perl, which is why LuaJIT is so popular. But LuaJIT is really just one guy’s project. Its metaprogramming features are really nice and let you build some Lisp-style DSLs, and if you want full Lisp syntax you can drop in Fennel. If you’re just writing extension code you often don’t need a standard lib because it’s easier just to roll your own function to fill the gap.
Personally, I found it easier and quicker to just read the reference manual to learn the language. It’s small and simple enough that you shouldn’t have trouble getting up to speed if you have a couple other imperative languages under your belt. IMO metatables are much easier to work with than JavaScript’s prototype inheritance.
Interesting, it looks like you can use ´global myvar’ now, as compared to ´myvar’ implicit globals, say from back in 5.1, or ´local myvar’.
It’s worth noting that global is a reserved keyword now, so environments that had a ´global()´ function for escaping environments will now need to rename their helper function.
But.. why ? Globals are just variables that reside in the wrapping env table that also contain the C functions. If a closures is a onion of table lookups out of the function context from local -> function scope -> global scope is simply the last lookup before a not found variable with nil is declared?
How hard is it to put a simple hello world example on the homepage.
Because Lua's Hello World is just `print("hello, world")`, which looks a lot like Python and doesn't tell you much about actually using the language.
One of the new features I found interesting, declarations for global variables, is buried in the reference manual. Here's a link to the section that discusses it: https://www.lua.org/manual/5.5/manual.html#2.2
I feel like Lua is absolutely underrated. I just wish one of the mainstream browsers actually puts their foot down and starts supporting Lua as scripting language.
I think that's doable. https://github.com/zacharie410/lua-browser-dom-demo
Ypu could probably run it in wasm. Of course, without access to the DOM it won't go any further than anything else on wasm. The whole thing is nuts if you ask me. So much lost potential.
If they can lock it to some version to avoid breaking code every time there is a new Lua version. Or Lua stop making breaking changes.
Curious how this fits in with WASM
ConTeXt has been using beta versions Lua 5.5 for a few years now, so you can look through its source [0] or try running it [1] if you're curious what a large codebase written in Lua 5.5 looks like.
[0]: https://codeberg.org/contextgarden/context
[1]: https://wiki.contextgarden.net/Introduction/Installation
> for-loop variables are read only
Seems like an odd change, I wonder what the rationale is. Just making it clear to people new to the language that you can't adjust it mid-loop to change the loop count I guess?
In previous versions, you could change it mid-loop. This apparently caused some unintuitive behavior when paired with generators (e.g. `for k, v in pairs(table)`).
I haven't run into this myself, but it does make sense, and eliminating this footgun sounds like a good idea.
From the manual:
We never got a new edition of Programming in Lua for 5.4... does that mean we won't ever get one for 5.5?
Oh I hope that don't do that.
List of changes: https://lua.org/manual/5.5/readme.html#changes
OG torch strikes back?
Excellent new release, now for Fennel and Love2d to update, fun times!
Cannot wait for another version of Lua to sit unused basically everywhere.
Truly is a shame, everything seems to have settled on 5.1 for the most part without ever being updated, or any intention of it being updated. Some really nice features post 5.1
I understand each version of Lua introduces breaking changes in the language, which isn't great as the language becomes fragmented (Or not really, once again 5.1 is pretty ubiquitous)
The real reason everyone settled on Lua 5.1 is because that's the version LuaJIT is compatible with, and most people are unwilling to give up the performance gains.
And Luau.
5.1 (by way of LuaJIT) gets a lot of use, but to suggests no one uses the modern versions is just not true. Lua being an embedded language just takes the pressure away to upgrade. It's a feature, not a bug.
> everything seems to have settled on 5.1
Not exactly. LuaJIT has backported various hot features from 5.2 and 5.3 as long as they're unlikely to break 5.1 code.
True. But
1. The luajit documentation basically just had a list of features. AFAIK there isn't any documentation that combines the 5.1 reference with luajit extensions (including things that were backported)
2. In some cases, for example Neovim, luajit extensions aren't guaranteed to be available. It just says there will be a lua runtime compatible with 5.1. Which means a truly portable neovim plugin can't use those extensions
3. There are features from later lua versions I would like to have (in particular <const> and <close>) that will probably never get backported.
4. Some features require luajit to be built with special flags
I'm pretty sure that's only OpenResty's distribution of LuaJIT.
I think the real LuaJIT is strictly 5.1
Not true, see "Extensions from Lua 5.2" here: https://luajit.org/extensions.html
No, real LuaJIT has some features from 5.2 and 5.3
https://luajit.org/extensions.html
I never coded in Lua but I found out recently that Lua is now in FreeBSD base [0] This is huge for Lua and FreeBSD.
Now something that worry me is whenever you need to make an HTTP request or parse some JSON you need to go on a quest for a "library" on the Internet. It doesn't seems to have a (semi-)official "Extended Standard Library" I can quickly trust.
- [0] https://man.freebsd.org/cgi/man.cgi?query=flua&apropos=0&sek...
The Lua ecosystem is more like the Lisp ecosystem than Python. The language is small enough that there’s a lot of stuff out there that’s just… finished. Hasn’t been updated in 10 years but still works. The LunarModules org tries to gather it up and keep it compatible.
For an extended standard lib, the closest thing is probably Penlight. https://github.com/lunarmodules/Penlight If you want async IO, sockets, etc, check out Luvit. https://luvit.io
Lua is really designed as an extension language but it’s such a nifty little language that sometimes you really wish you could use it in place of Python or Perl, which is why LuaJIT is so popular. But LuaJIT is really just one guy’s project. Its metaprogramming features are really nice and let you build some Lisp-style DSLs, and if you want full Lisp syntax you can drop in Fennel. If you’re just writing extension code you often don’t need a standard lib because it’s easier just to roll your own function to fill the gap.
Personally, I found it easier and quicker to just read the reference manual to learn the language. It’s small and simple enough that you shouldn’t have trouble getting up to speed if you have a couple other imperative languages under your belt. IMO metatables are much easier to work with than JavaScript’s prototype inheritance.
please resurrect Mike Pall
Mike Pall made a commit to LuaJIT just a couple of weeks ago.
Interesting, it looks like you can use ´global myvar’ now, as compared to ´myvar’ implicit globals, say from back in 5.1, or ´local myvar’.
It’s worth noting that global is a reserved keyword now, so environments that had a ´global()´ function for escaping environments will now need to rename their helper function.
But.. why ? Globals are just variables that reside in the wrapping env table that also contain the C functions. If a closures is a onion of table lookups out of the function context from local -> function scope -> global scope is simply the last lookup before a not found variable with nil is declared?
Module exports with side effects, and setting environments doesn’t guarantee global access.