> For compatibility with other computer languages, the following classic Lua operators can be written in a more customary syntax:
Why though? What does changing `and` to `&&` actually achieve? Were people confused?
Changing the syntax seems very surface level. It's not actually fixing any problems, just making Lua no longer look like Lua. It's not going to help anyone write/learn Lua. It will make everything more complicated as there are now two ways to do everything.
This feels like adding braces to Python because you don't like indenting your code.
A comment <https://github.com/LuaJIT/LuaJIT/issues/1475#issuecomment-47...> has already been made on the issue regarding the ternary operator, recommending `if x then y else z` over `x ? y : z`. This is exactly how it's done with if-then-else expressions in Luau <https://luau.org/syntax/#if-then-else-expressions>, another language compatible with Lua, and makes it a ton easier to nest (especially with elseif) and I believe still easier to read than `y if x else z`.
The ternary operator is easy to nest if you put each clause on a separate line. Then it looks just like nested if-then-else.
I love the ternary operator as much as anyone. But dang if it doesn't get hard to read when there is are a few, nested even.
Does that operator compile to faster assembly that if I make the same logic with verbose `if` logic? Is that a language specific outcome?
cond1 ? res1 :
cond2 ? res2 :
cond3 ? res3 :
or_else_res
I find that so much harder to read compared to if/else or case/when in ruby.
The ? is basically an attempt to use fewer if/else, at the cost of condensed if-else like structure. I always need to look at both parts after the ? whereas in a single if or elsif I don't. case/when in ruby is even better here e. g. regex check:
def foo(i)
case i
when /^cat/
handle_cats
when /^dog/
handle_dogs
Tangently related but I’ve been deep in Lua recently working on a rust implementation that supports Lua 5.1-5.5 in one Rust Binary https://github.com/ianm199/omnilua.
My ultimate goal was to support LuaJIT in Rust as well but this does not make it easier.
This is amazing! Can a program call across versions? Like could we take a Lua 5.1 codebase and upgrade only a portion of it at a time to a new Lua version?
Never will I understand ternary operators. As soon as you introduce it, some chuckle heads want to use them everywhere. Worse if the syntax allows nested ternarys. I guess it keeps the language open for code golfing, but it otherwise seems like redundant syntax that at best saves a few characters.
That’s why “if” should just be an expression
This is the best answer in my opinion. Ternary is just sugar for an expressive if. LuaJIT seems to be focusing on adding new syntax though, maintainer might not be amenable to updating existing semantics.
I don't think if-expressions have to affect existing semantics. Basically, in the parser you would have two different kinds of AST nodes, one for when the `if` keyword is encountered in statement position and another for when it's encountered in expression position.
Right now, `if` in expression position is just a syntax error ("unexpected symbol")
Yep. Everything should be.
Lua basically already has ternary operators anyway since "and" and "or" short circuit. I also don't see the need of adding additional syntax for it.
local x = condition ? value_a : value b
local x = condition and value_a or value_b> The classic Lua idiom a and b or c has a pitfall when b is nil or false: then c is returned, even when a is truthy.
> E.g. true and false or 42 returns 42, whereas true ? false : 42 returns the (expected) false.
I find it most useful in languages that have non-mutable variables and you want to avoid a mutable variable or an extra function when the value comes from a simple condition.
I guess for the JS case it makes sense to be able to shave a few characters for file shrinking purposes, but generally I'm more biased to code clarity and "self-explainability"
That’s what compression is for.
I see JavaScript.
Some of these really look like QoL improvements. I'm not convinced ternary statements are an ergonomic improvement in particular. The examples given don't make a compelling case, 'visually tidy' is not the same as readable.
Worse, I see C (as in ! or &&), and Perl (as in manifestly more than one way to do it).
There are real improvements though, such as ?. and ??= that help with default-nullable everything.
Ternary is very useful, but it I'd rather see it implemented idiomatically:
pos += (if forward then +1 else -1)
So is LuaJIT resuming active development after a decade or so of only maintenance? Great!
A lot of these changes make sense (although some of them are a bit too TIMTOWTDI for my taste) - but perhaps LuaJIT 3 would benefit from a change of name as well? Certainly with all these changes, it would be more like a separate language than merely a JIT-compiled version of Lua.
>TIMTOWTDI
What on earth is this supposed to mean?
There Is More Than One Way To Do It.
That takes me back a bit. It's a perl-ism. I used to think it was a great design feature but I've come to strongly prefer "There should be one way to do it, and it should be obvious"
Interesting, thank you.
There is more than one way to do it.
Lua 5.3 (2015-01-12) added the bitwise operators:
https://www.lua.org/versions.html#5.3
https://www.lua.org/manual/5.3/manual.html#3.4.2
Looks like LuaJIT is catching up, but calling these "syntax extensions" is confusing. Is the intent to hold LuaJIT fixed against some earlier Lua version (I guess 5.1) and adopt newer syntax piecemeal?
I welcome the compound assignment operators. Playdate's version of Lua also has that extension.
Looks like LuaJIT is really going to fork away from Lua this time. After these changes, it won't be a compatible Lua 5.1 implementation anymore, it will be a new language.
So shouldn't it have a new name?
It could be opt in.
Are there any rough estimates on popularity of lua implementations? At this point it feels lua means luajit
not even close, because there are a lot of places where you can't run LuaJIT
Where can you not run LuaJIT? Genuinely curious
Wasm and platforms like iOS and Nintendo Switch (I think).
anywhere that does not allow self modifying code such as app stores.
Seems like a bad idea to actively diverge from Lua, hostile even, especially without at least a clear change of name.
+= and ..= are things i find i'm constantly missing in lua.
Personally im a fan of introducing ternaranary operator in lua. Everyone uses `x and y or z` as a ternanary which i find way more confusing than ?:
I thought luajit had completely stopped feature updates
What’s the Lua/LuaJIT story these days for bundling up all the scripts of an application into a single file? Is there a way to do the super convenient go-like thing?
There's a bunch of options from a Google search, but embedding it in a thin C program and building that with https://github.com/jart/cosmopolitan would be a pretty go-like experience, I'd think.
I personally use a hand-written C wrapper program (which is not much more than a dozen lines long), and then embed the Lua scripts using objdump. This isn't quite as easy as Go since cross-compiling C programs is often somewhat tricky, but Lua is very portable and has zero dependencies, so it's usually not too hard.
I’m confused I thought Mike Pall left luajit and Laurence Tratt took over as maintainer?
Mike Pall is to LuaJIT as PG is to Hacker News.
Edit: meaning he can come back anytime.
I would love to see all of these come to LuaJIT (and love2d to support the new version too). It’s nice that Lua is simple, the syntax changes should hopefully make Lua code even simpler to read too
> It’s nice that Lua is simple, the syntax changes should hopefully make Lua code even simpler to read too
But which Lua?
Lua as implemented by LuaJIT is a fork of the language at this point. It's not fully compatible with PUC Lua (the reference implementation) and LuaJIT does not support features from the latest Lua version.
LuaJIT of course.
Please don't, inscrutable bitwise operators are an accident of the past even in systems languages, let alone in a scripting language. I'm not against infix operators for bitwise operations, just please spell them out with keywords rather than giving them sigils.
Likewise, going from `and` and `or` to `&&` and `||` would be a dispiriting regression. This is something that Zig got right.
Doesn't Zig also have bitwise operators?
The btiwise operators library doesn’t go away
Cool to see this - ergonomic syntax will make it easier to recommend Lua. Hope the PUC team aligns with this.
Also, I love this kind of pragmatism:
> Exponentiation assignment a ^= b has been deliberately omitted to avoid a predictable pitfall: this is how xor assignment is written in most other computer languages. Also, a syntax for exponentiation assignment is rarely asked for.
A ‘defer’ for closing files or deleting temp files at the end of a script will make life more enjoyable.
What are some pragmatic embedded scripting languages of choice these days if one has to consider:
1) Ease of learning, ideally minimal deviant behaviour (eg i consider lua tables to be a new concept in itself)
2) Reasonably fast. Not as much as lua jit but even half would be good enough
3) Mature
4) Has Rust bindings
Lua. Lua tables are easy and awesome. My hobby language unites Lua tables with functions too.
Lua has a lot of useless syntax. For instance, the "then". I have been using ruby and python for many years. Lua is living in the old age here.
That's just one example of so many more. I get that lua occupies a useful niche with its focus on embedded systems, but lua is not really a well-designed language in general. JavaScript has a similar problem.
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