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Luon programming language

Luon programming language

126 comments

·December 13, 2024

owenm

This is an impressive achievement, given there’s a whole language plus IDE. Kudos to the author. I couldn’t see any indication of what the author plans to use it for - I hope he can share more below?

I’m intrigued by the LeanQt library as well that the IDE uses (https://github.com/rochus-keller/LeanQt) too.

Rochus

> what the author plans to use it for

Thanks. I e.g. re-implemented the Smalltalk-80 VM in Luon (see https://github.com/rochus-keller/Smalltalk/), and I consider implementing an Interlisp VM (see https://github.com/rochus-keller/gingko/) which uses LuaJIT, which was an important motivation to interrupt my Micron language project to implement Luon.

pkphilip

Amazing that you also managed to implement Smalltalk besides Oberon and Luon - all of them with IDEs!

Wow!

And by the way the startup speed of the IFE is just insane! it is actually faster than my simple text editor!

MomsAVoxell

One of the most delightful places I’ve used Lua recently is in TurboLua, which gives the Lua VM access to all the necessary signals/pipes for writing high speed network applications, among other things. (https://turbo.readthedocs.io/en/latest/)

Do you see there being a way to make a TurboLuon with current specs?

Rochus

I don't use TurboLua, but I think it's feasible to build a Luon adapter module if need be. The necessary 'extern' keyword is already part of the spec.

owenm

The Interlisp VM sounds awesome - I would love to see Notecards on Windows/Linux/Mac natively!

Rochus

What do you mean by "natively"? Ahead of time compiled, or just working? If the latter, the present VM is already available on the mentioned systems. In my version, Gingko, I additionally removed a lot of outdated code to increase platform independence.

zem

nice! do you feel like oberon has something that gives it an edge over more currently popular languages, or is it just a matter of personal preference?

Rochus

Actually, I only use original Oberon when I'm migrating the old Oberon systems. My interest lies in finding out how I would have to modify original Oberon to be as productive as I am used to with e.g. C++, but still adhering to the goal of simplicity. My version, which I call Oberon+ (and to which Luon is quite similar, whereas Luon is even simpler), goes in this direction.

Actually an "edge over more currently popular languages" from my humble point of view is the goal and maintenance of simplicity. The term is subjective, but if you look at many of today's completely overloaded languages, it is intuitive to understand.

emmanueloga_

Amazing project!

I get the appeal to write an IDE from scratch, especially if you are already an expert in writing GUIs with your framework of choice! I wonder if it would make more sense to spend that time writing a language server protocol daemon. That way, you could make your language available in any IDEs your users like that support LSP.

Rochus

I'm usually working on older machines on which the IDE's supporting language servers would be much too slow or wouldn't work at all because of incompatibilities. I like lean tools with little dependencies. But there is a parser in moderate C++, so maybe someone else will implement such a daemon.

devin

Could I ask why you find yourself working on older machines? Work? A fan of retro computing? Something else?

dinosaurdynasty

Even VIM has support for LSP in extensions, I'm sure there's some lightweight LSP supporting editors out there.

pkphilip

I am actually glad that this person developed the IDE. Please download the IDE and try it. It is exceptionally fast. When I compare the speed with that of IDEs like Visual Studio Code etc, the difference is night and day.

null

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Rochus

If you want to hear the music, which I had in my head when I implemented Luon, here is the link: http://rochus-keller.ch/?p=1317 ;-)

bdunks

Wow! That’s impressive. The video at the top of your post really helped me understand the coordination involved. Thank you for sharing.

I imagine you’ve been playing music most of your life. How long did it take you to bring all of this together and start “one man band” improvising?

Rochus

Thanks. I actually started playing the piano in 1975. But only in the early 2000 I started to play bass on a pedal board. In 2010 I made my first experiments with playing the drums instead of the bass on the pedal board (http://rochus-keller.ch/?p=317). In 2014 I had a dedicated setup simulating a big band and played together with other musicians (e.g. http://rochus-keller.ch/?p=962). In 2022 I bought a Mac mini M1 and since enjoy the excellent sound quality of the new plugin generations. Only this year I managed to play the ride cymble as a real drummer would do it.

srhtftw

> locals can no longer be used before declaration

There's a lot I like about Lua but it so happens that a few days ago I spent longer than I'd like to admit debugging a trivial typo for Advent of Code day 5 that would have been caught by this.

Wondering if Luon will also prohibit or at least warn about storing nil in a table.

Rochus

Luon doesn't directly support tables, but instead supports records, arrays and hashmaps (which internally use tables). Since it's statically typed you can only store nil to a field or element if it is of a structured type.

akkartik

What's a structured type? Something that has fields or elements?

Rochus

Records, arrays and hashmaps are structured types; in contrast to original Oberon, Luon has no pointer type, but reference semantics instead.

hannofcart

This looks really good. It seems to fix all the warts and moles in Lua that used to exasperate me and adds type-safety which is a huge enhancement.

Replacing the 'everything is a table' with records, arrays and hashmaps is also a thoughtful improvement IMO.

Just confirming one point to make sure I understand the licensing implications correctly. Since the compiler transpiles to LuaJIT, and since that's just data, using output of the (GPL v2/v3 licensed) Luon compiler (i.e. the LuaJIT output) in a commercial/closed source project without divulging the source of said project should be fully kosher right?

Am guessing the answer is most likely in the affirmative but just making sure.

Rochus

Yes, what the compiler generates (LuaJIT bytecode in the present case) is not affected by the license which applies to the compiler. Usually, the runtime libraries which the generated code automatically depends on, are of bigger concern. Luon offers a GPL exception for the runtime code, as well as an LGPL or MPL license. So you can essentially use the runtime code for any purpose.

omoikane

Luon looks mostly like Oberon and not so much like Lua, it's not obvious which of the Lua features it incorporated. It didn't seem to have coroutines, for example.

But I am glad that it went with Oberon's 0-based array indices, as opposed to Lua's 1-based table indices.

https://github.com/rochus-keller/Luon/blob/master/specificat...

Rochus

> Luon looks mostly like Oberon and not so much like Lua

Luon can indeed look similar to Oberon if you use upper-case keywords and semicolons, but there is not need for this. Both - Lua and Luon - have much in common with Modula-2 (given lower-case keywords). There are many elements in Luon which are pretty similar to Lua, e.g. constructors, pcall, most control and loop statements. But there are also significant differences of course, because Luon is a statically typed language and Lua isn't.

MaysonL

Modula-2 – a blast from my past. Back in the ‘80s I used it to implement a prototype distributed OS (as designed by a team at JPL) on VAXen. Logitech (!) had a really nice VAX compiler back then. One of the most productive 6-month stretches of my career. Luon looks like an answer to my unspoken prayers. Thank you!

Rochus

Welcome. Actually we learned Modula-2 when I was at ETH in the eighties, and I had even a job at DEC Switzerland for some time where I had to develop course ware for the VAX Modula-2 compiler, but it was from DEC as far as I remember (probably this one: https://github.com/GunterMueller/DEC-Modula-2). Luon is actually a subset of my Oberon+ language; maybe you want to have a look at it: https://oberon-lang.github.io/.

ninalanyon

Don't all of Wirth's languages let you use any ordinal as the array index? At leat in Pascal you can declare an integer subtype, say 7..17 and use that as the type of the index of an array. Then the first element is item 7.

The point being that both the start at 0 and start at 1 camps can have it their own way.

Rochus

> Don't all of Wirth's languages let you use any ordinal as the array index?

In Oberon, Wirth kicked out everything to the bare minimum, including subrange types. Array indices in Oberon start with 0.

fuzztester

>Don't all of Wirth's languages let you use any ordinal as the array index? At leat in Pascal you can declare an integer subtype, say 7..17 and use that as the type of the index of an array. Then the first element is item 7.

Can confirm that about Pascal, since I had used it a lot earlier.

Don't know about the other Wirth languages.

>The point being that both the start at 0 and start at 1 camps can have it their own way.

Yes, but that is not the only point. Another reason, and maybe the more important one, is that having such custom array index ranges, can more naturally fit the problem domain. In fact you can even use user defined types for the ranges, e.g. so you can define an array with Sunday to Saturday as the indices and the values of (the equivalent of) an enum representing 1) weekdays and 2) weekends, as the corresponding values.

Then your code involving days and weekdays and weekends, will read more naturally, so will be easier to both read and maintain. And you only have to do those custom definitions once, up front, so it is not much extra work for the benefit gained.

dmz73

I have a really hard time understanding why people like 0 based indexes. They are a relic of C style arrays that are based on and interchangeable with pointers which use offsets that are naturally 0 based. Use in later languages gives us endless off-by-1 issues and rise to "for 0 to count/len/num - 1" or even better range syntax that is start inclusive BUT end exclusive. It is a horrible cludge just to support 1970s language perfomace optimization. Arrays should start and end at whatever start index is required, not at offset 0 of pointer to fist element of array.

Benjamin_Dobell

Hang on. Off by one issues are the argument frequently given in favour of zero-based indices, not the other way around. For example, let's iterate through items placing them in 3 different groups;

JS:

    for (let i = 0; i < items.length; i++) {
        groups[i % 3].push(items[i]);
    }
Lua:

    for i = 1, #items do
        table.insert(groups[((i - 1) % 3) + 1], items[i])
    end
Don't get me wrong. I like Lua, I've made my own IDE for it, https://plugins.jetbrains.com/plugin/14698-luanalysis, but this is definitely not an argument in favour of 1-based indices.

geocar

Off by one issues are also an argument given in favour of no indexing.

    groups=new Array(3).fill([])
    items.reduce(function(a,x,y){y=a.shift();y.push(x);a.push(y);return a},groups)
Array languages typically have a reshaping operator so that you can just do something like:

    groups:3 0N#items
Does that seem so strange? 0N is just null. numpy has ...reshape([3,-1]) which wouldn't be so bad in a hypothetical numjs or numlu; I think null is better, so surely this would be nice:

    groups = table.reshape(items,{3,nil})   -- numlu?
    groups = items.reshape([3,null])        // numjs?
Such a function could hide an ugly iteration if it were performant to do so. No reason for the programmer to see it every day. Working at rank is better.

On the other hand, Erlang is also 1-based, and there's no numerl I know of, so I might write:

    f(N,Items) -> f_(erlang:make_tuple(N,[]),Items,0,N).
    f_(Groups,[],_,_N) -> Groups;
    f_(G,Items,0,N) -> f_(G,Items,N,N);
    f_(G,[X|XS],I,N) -> f_(setelement(I,G,X),XS,I-1,N).
I don't think that's too bad either, and it seems straightforward to translate to lua. Working backwards maybe makes the 1-based indexing a little more natural.

    n = 0
    for i = 1,#items do
      if n < 1 then n = #groups end
      table.insert(groups[n],items[i])
      n = n - 1
    end
Does that seem right? I don't program in lua very much these days, but the ugly thing to me is the for-loop and how much typing it is (a complaint I also have about Erlang), not the one-based nature of the index I have in exactly one place in the program.

The cool thing about one-based indexes is that 0 meaningfully represents the position before the first element or not-an-element. If you use zero-based indexes, you're forced to either use -1 which precludes its use for referring to the end of the list, or null which isn't great for complicated reasons. There are other mathematical reasons for preferring 1-based indexes, but I don't think they're as cool as that.

Jerrrry

Your second example subtracts and adds 1 nearly arbitrarily, which wouldn't be needed if the convention of the 0-index wasn't so widespread.

binary132

why not just iterate in steps of three over items for each next group? seems a bit contrived.

samatman

Having done fairly extensive parsing work in Lua and Julia on the one hand (one-based), and Python, Javascript, and Zig on the other (zero-based), the zero-based semiopen standard makes intervals dramatically easier to calculate and work with. It's really the semiopen intervals which make this the case, but as the Word of Dijkstra makes clear, zero-basis comes along for the ride, to combine semiopen intervals with a one-basis is perverse.

Naturally it's true that for collections and naïve indexing, 1-based is more natural. But those are rare places for bugs to occur, while interval calculations are a frequent place for them to occur.

Clearly I'm far from allergic to the other standard, but I come down on the side of the zero basis for that reason.

umanwizard

I have a really hard time understanding why people like 1-based indexes! 0 is the smallest unsigned integer in every programming language I know of that supports the concept of unsigned integer. Why shouldn’t an array at the smallest possible index correspond to the beginning of the array?

It’s also very natural to think of arr[i] as “i steps past the beginning of arr”. With one-based indexing arr[i] has no natural interpretation that I know of. It’s “i-1 (for some reason) steps past the beginning of arr”. The only reason I can think of to prefer that extra -1 in your formula is just because human languages (at least the ones I know of) work this way — the 42nd element of a sequence, in normal colloquial English, means the one 41 steps past the beginning. But I’m not sure if there is any logical justification for that.

I also, despite being American, find the convention used in many countries of numbering building floors starting with zero to be more logical. I’m on the third floor, how many stories up did I travel to get here? Three.

geocar

> Why shouldn’t an array at the smallest possible index correspond to the beginning of the array?

Because then there is no good way to refer to the index before that point: You are stuck using -1 (which means you can't use it to refer to the end of the array), or null (which isn't great either).

> every programming language I know of that supports the concept of unsigned integer

Surely you know Python which uses a signed integer as an index into their arrays: list[-1] is the last element of a list. If they only used one-based indexing then list[1] would be the first and that would be nicely symmetrical. It would also mean that list[i-1] would NEVER refer to a value after ‹i› eliminating a whole class of bugs.

> It’s also very natural to think of arr[i] as “i steps past the beginning of arr.”

I think it's more natural to think of arr[i] as “the ‹i›th element of arr” because it doesn't require explaining what a step is or what the beginning is.

The exact value of ‹i› matters very little until you try to manipulate it: Starting array indexes at one and using signed indexes instead of unsigned means less manipulation overall.

> find the convention used in many countries of numbering building floors starting with zero to be more logical

In Europe, we typically mark the ground-floor as floor-zero, but there are often floors below it just as there are often floors above it, so the floors might be numbered "from" -2 for example in a building with two below-ground floors. None of this has anything to do with arrays, it's just using things like "LG" or "B" for "lower ground" or "basement" don't translate very well to the many different languages used in Europe.

The software in the elevator absolutely doesn't "start" its array of sense-switches in the middle (at zero).

fuzztester

In India too, the floor at the ground level is called the ground floor (probably that is where the name came from), the one above it is called the first floor, and so on. The convention is probably from British colonial times.

Also LED floor numbers in lifts (elevators) in India start from 0 for the ground floor, as do the buttons that you press to go to specific floors.

Also, Ground Zero.

https://en.m.wikipedia.org/wiki/World_Trade_Center_site

https://en.m.wikipedia.org/wiki/Hypocenter#

nkrisc

> I also, despite being American, find the convention used in many countries of numbering building floors starting with zero to be more logical. I’m on the third floor, how many stories up did I travel to get here? Three.

Alternatively the ground floor is the first floor because it’s the first floor you arrived at when you entered the building.

The same point of view applies to 1-based indexing.

That said I prefer 0-based in programming and 1-based in buildings.

Netch

> find the convention used in many countries of numbering building floors starting with zero to be more logical.

Ukrainian here. Multi-floor buildings always have at least one stair section to first floor due to need of thermal basement isolation. (I guess this is not pertaining to Western Europe due to more clement winters.) And, yep, it is called "first" floor. Using zero number is rare but possible (in this case it is called "tsokolny" floor) if a real "basement floor" is present, but in this case still 1-based numbering is preferred.

jhbadger

I'd argue that 1-based indexing is the "natural interpretation". Mathematics is inherently 1-based, and it isn't surprising that languages designed to do mathematics like R, Matlab, Mathematica, Julia all do 1-based arrays because that makes modeling paper mathematics in programs easier.

teo_zero

> [0-based indexes] are a relic of C style arrays

I don't think this is true. They exist in other disciplines (maths for instance) that have no relationship with C or other programming languages from the 1970s.

> for 0 to count/len/num - 1

I will counter saying that such a for...to syntax is a relic of BASIC.

> or even better range syntax that is start inclusive BUT end exclusive

I know that your "better" is sarcastic, but I actually find left-inclusive+right-exclusive ranges fantastic. They allow perfect partitioning, easy calculation of lenght, etc.

> Arrays should start and end at whatever start index is required

I agree. An accommodating language would let you define both lower and upper bounds of an array, instead of its size.

fuzztester

IIRC some BASIC(s) I've used in the past had a statement called:

OPTION BASE 1

or something like that, to change the starting index to 1.

fallous

There are 360 degrees in a circle, and the first entry is 0 degrees. The first time element of a day is 0:00:00(and enough 0s to satisfy whatever resolution you require). These were not established in the 1970s, and somehow pretty much everyone understands and works quite well with these systems.

brabel

> There are 360 degrees in a circle, and the first entry is 0 degrees.

To be pedantic, "first" is associated with 1. And a circle does not have a "first" entry, whatever you mean by entry. I think what you're trying to say is that a circle is a continuous arc going from 0 to 360 degrees, but you should recognize that the "starting point" is arbitrary, any point will do, so there isn't really a "first", and that this is not the same as counting because counting is done with natural numbers, which are non-continuous. The problem of 0 VS 1 makes sense only in counting exactly because it's subjective whether you prefer to count from 0 or from 1. Because zero is the absence of anything, I find it hard to start counting from 0 (when you do, your "first" item is actually your zeroth item, and the next item would be the "first"??!), to be honest, despite being completely familiar with doing so since I've used 0-index programming languages my whole life.

umanwizard

Also, how many years old are you when you're born? Zero. (at least in mainstream Western culture).

coder543

Some countries consider the 1st floor to be the ground floor, others consider the 1st floor to be the floor above the ground floor, which the formerly mentioned countries consider the 2nd floor… I think 0/1-based indexing is more subjective than simply being a “relic of C” or a “horrible kludge” :P

zem

I've been in the US for over a decade and it still occasionally makes me double-take when a room numbered 1xx is on the ground floor

teddyh

Here’s the ultimate authority on why computer languages should count from zero:

<https://www.cs.utexas.edu/users/EWD/ewd08xx/EWD831.PDF>

umanwizard

I find that argument to be written in a terse "mathy" style that makes it a bit hard to follow. So let me try to restate it in more concrete "programmy" terms.

To iterate over an array with "len" elements, it’s most elegant if “len” appears as a loop bound, rather than "len+1" or "len-1". Thus, in 0-based languages we use half-open ranges, whereas in 1-based languages we use closed ranges:

  // real C
  for (int i = 0; i < len; ++i)
      process(array[i]);


  // C-like language with 1-based indexing
  for (int i = 1; i <= len; ++i)
      process(array[i]);
But the second is inelegant when len is zero, because 0 isn’t a valid index at all, so it’s weird for it to appear as a bound.

thefaux

Yeah, I disagree with Dijkstra on this. And many other things.

ofalkaed

>They are a relic of C style arrays

Doesn't it predate that by a good amount? I would think it is a relic of the EEs who built the digital world, those early languages show a great deal more relation to the bare metal than modern languages. Creating an array whose index starts at 1 just doesn't make sense from the discrete logic point of view, you are either wasting an element or adding in an extra step.

But in this day and age how can a language not have ⎕IO ← 0?

HexDecOctBin

Is this purely a personal project, or is it supposed to be used by others? You have made so many languages in the Oberon family (great job keeping the traditions alive, by the way), it's hard to know whether they are just a personal experimentation or you are expecting others to use them too.

Rochus

This is not actually a contradicion, and the audience will decide whether the language will be used more widely. It's not my first priority, but there's nothing against it either. What you call "tradition" applies to my experiments with the Oberon Systems and the backward compatibility with their source code (for practical reasons, otherwise I would not be able to compile them), but my interest is actually in the language adapted for today's meaning of simplicity, which I call Oberon+ (or Luon, or Micron), and which would definitely have the potential for further adaptation if you look at what kinds of new languages are popular at the moment.

stevage

It's nice when a project can find such a simple pronouncable name that is also meaningful.

robertlagrant

I keep thinking it's called Luberon, which probably isn't helpful.

1attice

I confess I was worried, until I read the name explanation, that it was named after Lululemon's marketing term for its preferred elastane/cotton blend

Rochus

Funny; it's actually surprisingly hard to find information; but Perplexity told me, that Lululemon's Luon is a material which has great flexibility and maintains its shape over time, wicking away sweat, and good coverage; all good features for my programming language ;-)

imtringued

I would have preferred a typescript equivalent for Lua. This is a bit too radical for a casual Lua user.

k__

Why use a language with Oberon syntax, when there's Teal, which has Lua syntax and a TypeScript to Lua compiler?

speed_spread

Because Pascal/Modula/Oberon is the one true language. TypeScript? Blasphemy!

k__

What's Oberon's unique selling point?

MarcusE1W

Quite high abstraction for its simplicity, quick to learn, strongly typed, garbage collected before it was cool (same as Module 3) and yet a system programming language (Oberon OS).

You could argue that Wirth overdid it a bit with the simplicity vs. Comfort features but that's probably also dependent on your preferences and the problem you want to solve.

There are a few languages where you regret that they did not win in favour of C++ and Oberon is one of them (and Modula 3). Not that C++ does not have its strength , but for many problems Oberon would probably have been the simpler fit.

humptybumpty

Cute name: ”Luon” means ”I create” in Finnish.

Rochus

So let's create ;-)

null

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