Jai Language Primer

https://github.com/BSVino/JaiPrimer/blob/master/JaiPrimer.md

by aerique • 10 years ago

44 96 10 years ago

danbolt• 10 years ago

I like the idea of a language syntax that allows easier refactoring. I think Rust is especially good at this as well, and I'm happy to see that Jai borrows from that.

giancarlostoro• 10 years ago

I liked some things I saw which I've only seen in Pascal / Ada.

Edit: Specifically I thought it was the same as what I've seen in Pascal for arrays[0] where you specify the range (in the case of characters) between x and y. I always thought that was kind of interesting, have yet to really see it implemented in another language afaik.

[0]https://en.wikibooks.org/wiki/Ada_Programming/Types/array

beagle3• 10 years ago

Nim is a modern Pascal/Delphi with a Pythonic syntax. You'll probably like it.

whitegrape4• 10 years ago

I wonder if Blow has ever looked at Nim. Sometimes I hallucinate that game devs will have an Awakening and realize it's the way forward.

aerique• 10 years ago

I've got the same dream but about Lispy languages, preferably Common Lisp.

I'm sure more people around here have the same dream about their favorite language :-)

whitegrape4• 10 years ago

Every now and again when I'm really figuratively toked up I go reread the history of Crash Bandicoot and also dream for more Lisp in the games industry (and every other industry). :) But I think Nim is slightly more realistic.

davexunit10• 10 years ago

I look at all these new languages with horrificly complicated syntax and wish for s-expressions. Lisp is perfectly well suited for game development, too, and not just for scripting. There are many implementations around with fast optimizing compilers, JIT compilers, and other modern features that make things run fast. When I see languages like what Jonathan Blow made, I think that most of the features can be implemented as extensions to your Lisp of choice.

weavie• 10 years ago

Yes, how much fun folks could have if you could connect a Repl into your game and arbitrarily change the rules on the fly!

CyberDildonics17• 10 years ago

Doesn't Nim use garbage collection?

Also the compiler isn't even stable, it is an interesting language but can't be take seriously for professional development yet.

whitegrape4• 10 years ago

Use of GC in Nim is up to you -- you can malloc/free as you please if you want and avoid it altogether. I'm not sure to what extent you can/can't make use of the standard library if you avoid GC, but even if you lessen your restrictions and use it a little bit, it's a highly tuneable/controllable and understandable GC including support for swapping out entirely different GC algorithms.

Professional game development as in AAA studios? Yeah, probably not, but more for the tooling alone than whatever language any particular studio happens to use. Professional indie game development? It's ready, even though it's not at 1.0 yet. Indie devs deal with big breaking upgrades to their frameworks (Unity, Corona, etc.) all the time, it's annoying but not a deal-breaker if the language gets those sometimes too.

jfaucett• 10 years ago

This is interesting. Recently, I've been doing more c programming again, and everytime I do I find myself thinking about building a language that is essentially c with just a very few pain points removed. #1 is a build/module/package system for making it easier to build modular code without copy/paste that is the defacto c-standard. #2 would be removing the pain points of utf8/unicode support (go seems to get this pretty close to right). And that's really it. (you could throw in an easy way to do closures and all values immutable by default and I wouldn't mind either).

Otherwise, I'm usually completely happy using C. I've tried Rust and Go and they have their use cases, but for most low-level things I do, I don't care that much about everything being perfectly safe (i.e. rust), and I don't want gc, and the high level stuff that Go brings. Really, just give me C with a good module system and I'd be perfectly happy. Maybe I'm alone here though...

TheAceOfHearts• 10 years ago

Have you seen dotc [0]?

[0] https://github.com/substack/dotc

CyberDildonics17• 10 years ago

It has been said that everyone wants their favorite language with just one more feature.

davidgrenier• 10 years ago

I stopped caring at no garbage collection.

frou_dh• 10 years ago

Your announcement has been placed in the special filing cabinet.

gregstula12• 10 years ago

Do you know why Microsoft rewrote Minecraft in C++?

Games can certainly be successful in spite of performance problems, but why purposefully introduce them in the first place?

In the case of Notch, he used Java because he was most skilled at Java programming. The garbage collection, procedural generation, and multi-platform availability of the JVM allowed him to successfully release a massive hit as a solo indie developer.

At least that's one way to interpret it. Another way is that, had Notch been as skilled in C++ or (these days) Rust he could have made just as good of a cross platform game (even more so on mobile), that didn't concern itself with resource management outside of RAII and reference counting, was way more performant (no pauses), and in similar time frame as a skilled Java developer.

If you have a great idea use your favorite language. No doubt about that. You might be successful in spite of its specific deficiencies. However, if you are seeking a new language for a certain problem domain - like video games - choosing one with a feature that actively fights one of your fundamental goals (consistent framerate is only going to be a decision your users will regret you made.

It's funny that people like to say "users don't care what language it's written in". The fact that 8th graders know the the minecraft's garbage collector is a problem, suggests that using a garbage collected language for soft-realtime video games results in a seriously leaky abstraction.

hacker_93• 10 years ago

Minecraft is a special case, as the amount of voxels in memory and the constant loading and deloading of blocks of the map every few seconds, means that memory management is incredibly important to the game. That's why the C++ version was more performant, as John Carmack had full control of both the memory layouts and lifetimes, and could fine tune it all to fit the game.

This is the only reason C++ is still in wide use today, in order for games to limit load times they have to do nasty 'unsafe' tricks (such as loading a block of memory from disk straight into an address space, and just assigning pointers to it), in order to get good performance. But if your game isn't open world (such as minecraft, GTA, Fallout), then using a garbage collected language will be fine (as long it's not stop the world, but runs concurrently).

greggman4• 10 years ago

I'm with you on this. I'm an old school gamedev. Shipped games on Atari 800, C64, NES, and most system since then. I hated garbage collection for the longest time.

But, I have to acknowledge plenty of games are shipping with garbage collection. Unreal has garbage collection. Unity games have garbage collection. They seem to all be running just fine and there's plenty of large AAA games or close to AAA games made with both engines.

gregstula12• 10 years ago

They do not have garbage collection. You're conflating game development with game engine development. When a big powerful, flexible, C++ engine has been written for you, you can use C# or JavaScript or BluePrints to use the engine to make a game.

eropple• 10 years ago

Unity has garbage collection at the userland/scripting level. This is markedly different from garbage collection at, say, the level of the objects that marshal and keep tabs on your OpenGL resources. (Not least because--though AFAIK Unity does not do this--you can stop the world for GC only at the scripting layer rather than taking out your rendering, sound output, etc. as a side effect.)

dang• 10 years ago

You've posted several such dismissive comments to HN. Please don't do that any more.

Substantive criticism is fine, but it should be thoughtful, not snarky and shallow.

gregstula12• 10 years ago

Abstractions like RAII, constructors and destructors, polymorphism, and exceptions were invented with the intention of solving problems that game programmers don’t have

This is the only part of the Jai philosophy I struggle to understand. How is an explicit delete keyword better than deterministic destruction? From my perspective, the former method reintroduces the problem the latter method solves.

Also, polymorphism is bad for games now? I absolutely cringe when I see abstract base classes, virtual functions and classical inheritance, outside of a generic interface in 2016. However, games might be the one case I would strongly consider using those features as part of my design. For example, a Final Fantasy-style job system seems to elegantly lend itself to the "Intro to OOP with C++98" style of runtime polymorphism*

As for exceptions, well I think the reputation of exceptions is one of the great tragedies of C++. Rust, Go, and other new languages seem to have decided that regressing to pervasive error checking boilerplate is more elegant than to have exception handlers.

I think Swift got it right with scoped exceptions and a defer statement - although, they selectively use "error handling" as double speak to avoid saying the e-word.

*Although, I personally think interface/protocol based solutions have proven to be the cleanest way to tackle polymorphism -- this is possibly true even in the case of an rpg with class inherentence as a game mechanic.

w0utert2• 10 years ago

> This is the only part of the Jai philosophy I struggle to understand. How is an explicit delete keyword better than deterministic destruction? From my perspective, the former method reintroduces the problem the latter method solves.

My interpretation of statements like "problems game programmer's don't have" is that they don't mean game programmers don't run into situations where things like RAII or polymorphism would be useful, just that the stereotypical game programmer doesn't care about using them because they have their own ways to get the same results. Which often involves programming practices that aren't considered safe for most other application domains.

The thing with 'game programmers' when referring to people like Jonathan Blow and e.g. Casey Muratori (who does Handmade Hero), is that they have been writing the same kinds of systems for so long, and have developed so much 'muscle memory' to avoid the pitfalls of their coding style, that they appear to have gotten a blind spot for all the deficiencies in the code they write. It works, it's efficient, and someone with the same mindset could make progress on it despite of the minefields they've created, but it's usually not 'good code'. The Handmade Hero code for example is atrocious if you ask me.

It never ceases to amaze me how people who are so smart, much smarter than myself, fail to acknowledge all the ways in which they could write better code without throwing out any of the goals they've set for themselves (performance, compilation speed, predictability, ...). All things considered, it does not surprise me that so many games ship in a half-broken state.

ilek3• 10 years ago

Out of interest, why do you think the Handmade Hero code is atrocious?

I haven't kept up with it so I don't have much of an opinion.

alaties• 10 years ago

Would you mind explaining or linking to a good document on "C++98 style runtime polymorphism"?

autoreleasepool3• 10 years ago

You can do a google search for this information

CyberDildonics17• 10 years ago

There are cases where virtual functions lend a lot of flexibility, but for games they are usually a sign of a programmer that doesn't understand how pointer chasing destroys performance. If you look at Ogre (and I think box2d) both architectures could be massively sped up by not using arrays of pointers.

pandaman10• 10 years ago

Games (I am talking about AAA here, have no idea about all possible games) are not written in the style that leaves place for constructors/desturctors. The data is better in tables (i.e. arrays) than spread all over the memory and accessible through a pointer network. The reasons being: a) walking an array is orders of magnitude faster than walking a pointer chain and b) heap allocation wastes more memory

This, in turn, makes no sense for polymorphism since you already have uniform data in the arrays there is no need to do an expensive indirect jump to figure its type.

gregstula12• 10 years ago

Why couldn't you use a structure to encapsulate the table and then have the destructor to deallocate the the array?

This is how vector works.

BSVino• 10 years ago

Hey there. I wrote the Jai Primer. Ideas there are my best interpretation of Blows ideas, which I generally agree with, but bear in mind they're not his.

To quote Joe Armstrong: You wanted a banana but you got the gorilla holding the banana and the whole jungle. You wanted a way to delete memory automatically, which sounds great but in practice most language's approaches to solving this problem come with a host of other problems that at scale make the given solution not worth it. RAII solves a big problem but it introduces a bunch of tiny problems like big mysterious constructors that implicitly do a lot of work and deconstructors that don't map to any particular line of code other than an ending brace. It's tough to examine in a debugger, it's tougher to reason about when it gets to nontrivial scale, etc etc. But human brains naturally weight a lot of small pains to be less bad than one big pain, so the solution looks legit.

Polymorphism is a way of modeling the world that runs along the lines of the categorizations that people tend to make, so it feels natural to create deep class hierarchies. But in practice it doesn't match the problem that you need to solve when you make games - you have data in state A and you need to get it into state B. Example: to do a physics integration on each simulated body, the CPU wants to do a for loop over a list of position vectors. But those vectors have been scattered all over memory by the class hierarchy. So that's one problem, you also get problems like needing RTTI and casting and yadeya. Class structures have largely fallen out of vogue in game development in favor of component systems, which is a pretty good step forward.

CyberDildonics17• 10 years ago

One language to look at for reference that most people haven't heard of is Clay. It isn't kept up any more, but it's aim was to be a modern generic C. It made use of very clean generic programming with move semantics and no garbage collection. The person who wrote it was using it as a substitution for C at his work already.

oconnor0• 10 years ago

Maybe because it hasn't been updated in 3-4 years?

steveklabnik• 10 years ago

There are a lot of languages which are "dead" but are useful to look at when you're designing a new one. Clay is certainly one of those if you're looking at building a low-level language.

dom96• 10 years ago

What's cool is that Clay's designer is now working for Apple on Swift https://github.com/jckarter

gnuvince• 10 years ago

I remember Clay, it was mentioned on Reddit for the first time around the same time I first heard about Rust (back when Rust was a very different beast). I though Clay was very interesting, it's a shame it is more or less abandoned.

CyberDildonics17• 10 years ago

Looks like that is the current maintainer. The original designer was someone name KS Sreeram http://kssreeram.org/

gcatlin• 10 years ago

Jonathan Blow is currently doing an AMA on reddit right now https://www.reddit.com/r/IAmA/comments/45fu74/i_am_jonathan_...

Jai Language Primer

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