7 ms·

Kit Programming Language

115 points by BerislavLopac 8y ago

CoderCV 8y ago
Another programming language. God! I have no idea - what's happening to the world? Are people not skilled enough to propose or send commits to an existing or alternative programming language? There is Rust, Go, Julia, Clojure, and many other... What is the primary reason to create a new programming language?
- annywhey 8y ago
  Another "too many programming languages" comment. God! I have no idea - what's happening to the world? Are people not skilled enough to evaluate new languages? There are new type systems and static checks, integrated build systems and package managers, backwards-compatibility features, debugging tools... What is the primary reason to complain about new programming languages?
- flohofwoe 8y ago
  Rust, Go, Swift, etc... are like super-tankers compared to those small "better-C" languages. IMHO, having a number of small languages that can be learned in an afternoon is much better than yet another super-tanker designed by huge consensus-driven committees/communities that try to do everything for everybody.
  - carlmr 8y ago
    Rust has safety and zero-cost abstractions at it's core, they provide a by now quite stable interface. You can't just move fast and break things. You need to stabilize at some point or it's impossible to use it in real world projects that are also commitments of a certain kind. And for that stability you need some kind of consensus of what to work on and what not to do. I think the primary value of these new toy languages is they can explore aspects freely that can't just be explored in a more mature language. Sometimes after a concept has proven useful a mature language might be willing to incorporate it. But I wouldn't use them on a serious project, because there will probably be few libraries and maybe no long term support for it.
    - bendmorris 8y ago
      These are valid concerns, particularly stability and long term support. Availability of libraries applies less to Kit or Zig thanks to first-class interoperability with C. I think this is the way forward for small new languages; you can avoid the challenge of creating an entire ecosystem for your language, and just fit it into an existing one.
  - eriktate 8y ago
    I'm surprised that you would lump Go in as a "super-tanker" language. I find it incredibly small and simplistic when compared to something like Rust. I think it actually has fewer keywords than C.
    - renox 8y ago
      Go the language OK but Go rely on a GC which required lots of work..
- tragomaskhalos 8y ago
  Suspect that in the majority of cases it's a bit like people inventing their own (human) constructed language - it's an interesting intellectual exercise in its own right and allows the inventor to indulge in a bit of wish fulfilment by emphasising features that they personally value. As in the human conlang case, it would be alarming or bizarre if the inventor genuinely expected others to start coding in their language, especially if it has no compelling features that are not found elsewhere: although Perl, C++, Rust and others came primarily from motivated individuals "scratching an itch", those langs were able to flourish because they fill(ed) an empty evolutionary niche. What I do find peculiar is other people then piling in with all sorts of suggestions for enhancements and tweaks that imply that the particular hobby language in question does have a legit future out in the field.
- coldtea 8y ago
  >Are people not skilled enough to propose or send commits to an existing or alternative programming language? How would those "alternative programming languages" you propose have been created if people followed your "advice"? We'd still be sending patches to C and C++ or perhaps Algol? >What is the primary reason to create a new programming language? 1) Because you feel like it and you don't need to have approval for anybody to do so. 2) Because you want to explore some particular syntax/semantics combination other languages don't offer. 3) As a training exercise. 4) To cover some very specific needs you have, and don't like how other languages do it. 5) To introduce some new ideas into PL design, which might or might not be adopted by users or by a more mainstream language.
  - eksemplar 8y ago
    C++ had a purpose though, to create object oriented C. A lot of these modern languages seem to be mainly made because someone could. With so many there is also a very low chance of any of them actually picking up because the useless ones drown out the C++es. I think people should do what they want though. If you want to make a programming language you should, just don’t expect everyone to view your endeavors as useful. As far as your fifth point goes, new languages aren’t a good way to influence programming in general. Stuff like lambdas weren’t born in some hipster language, they came from JavaScript. Because if you want to influence, you have to make sure people actually see your stuff. That being said. Making a PL language is a much better use of your time than whining on HN.
    - flohofwoe 8y ago
      Many of those new languages are created because C++ failed to improve C in the areas that really matter: http://esr.ibiblio.org/?p=7724 http://esr.ibiblio.org/?p=7724
      - pjmlp 8y ago
        Actually it improved, what C++ compilers cannot prevent is for people to write C code with a C++ compiler, beyond outlawing it as bad practice. Copy-paste compatibility with C is a burden on modern computing, but it was also what contributed to C++'s adoption during the early 90's.
- efficax 8y ago
  I also find the march of new languages a little exhausting. But I handle that by just taking a glance at them and moving on. Kit never has to trouble me again and I'll have already forgotten it by the time I hit reply here. And my life will go on.
- otabdeveloper1 8y ago
  > What is the primary reason to create a new programming language? The reason is that creating a new programming language is easier than learning C++. For this same reason none of these languages will ever amount to anything useful. If you have the patience and foresight to bring a new programming language to fruition, then you have the patience and foresight to learn C++. You grow up and start programming in a real language.
  - bendmorris 8y ago
    I, uh...I know a little C++ :) I like to think that when I'm writing Kit, I'm writing C, so I am writing in a "real language." Total interop, no real drawbacks.
- bendmorris 8y ago
  >Are people not skilled enough to propose or send commits to an existing or alternative programming language? I'll just comment on this part. I'm a contributor to Haxe (not so mainstream perhaps but more so than Kit.) Kit was a chance to try out some features that don't fit in well to Haxe (and in fact I did propose several of these features as additions to Haxe, and they were explicitly rejected.) Sometimes the answer really is to write a new language, because language simplicity is still important and one language can't be everything to everyone. And of course, Haxe wouldn't exist if its creator hadn't been unsatisfied with existing languages at the time...
- AndyKelley 8y ago
  > Oh shit everything is already made guess I'll watch Netflix while I wait to die have fun with that
annywhey 8y ago
This looks like it takes influences variously from Haxe, Rust, and Haskell, which are all great in my book. But the first thing that crossed my mind was, "could it compile to other languages besides C?" The reason being that I think the way to really move up the baseline is to take another page from Haxe and aim for cross-compatibility between different systems languages, becoming a "language that unites them all". So that could mean relatively new and hip ones like Rust, D or Zig, or older ones like Pascal(Delphi), Fortran, Cobol... And those are niches relative to C, but they're nearly unserved niches AFAIK.
- flohofwoe 8y ago
  AFAIK languages "compile to C" mainly because they use C as an intermediate representation and the C compiler as the last stage of the compile/link process, so kitlang itself doesn't need to support code generation for various CPUs, and also doesn't need to implement an LLVM frontend. Instead it uses the target platform's C compiler, which is a lot less work but has basically no downsides. Also the C IR code might make it easier to interop with other languages, since C is basically the 'lingua franca' that all other languages can talk to in some form.
  - kibwen 8y ago
    > Instead it uses the target platform's C compiler, which is a lot less work but has basically no downsides. The downsides of leveraging a platform's given C compiler as your backend is that now you'll be spending a large chunk of time learning the hard way about all the various incompatibilities in C compilers, and adding workarounds in your frontend for the otherwise-unpatchable behavior encountered in every old version of every major compiler on every platform you wish to support. Conversely, the advantage of using a single known backend is that you can automatically know what code your users are running when they submit a bug report, and you can fork and ship the patch yourself rather than trying to convince an upstream C compiler to accept the patch, then convince the upstream distro to ship the new version of the compiler, then convincing all your users to update their platform C compiler. Walter Bright concurs: https://news.ycombinator.com/item?id=16195031 https://news.ycombinator.com/item?id=16195031 Kit may have an easier time of it if it's intended only for games, since that narrows down its supported target platforms substantially. The harsh truth is that most game devs only care about one platform (Windows) and one toolchain (MSVC), so at least it can tailor its output to appease MSVC specifically.
bitmadness 8y ago
This looks amazing! Does it support parallel/multicore programming?
xtrapolate 8y ago
> "Memory management in Kit is manual (no automatic garbage collection), with some convenience features to make this easier." I was curious, but there aren't any examples of this on https://www.kitlang.org/examples.html https://www.kitlang.org/examples.html
dvfjsdhgfv 8y ago
Anyone is actually using it? If so, could you compare it to Nim that also compiles to C?
rishav_sharan 8y ago
I am far more interested in the comparison between kit and Zig.
- forgotpwd16 8y ago
  Also Myrddin and C2 seem to target a similar niche.
  - earenndil 8y ago
    I've written about c2 before. It has some things that might be nice to have in c (header files, remove ->), and some things that make Zero sense to have in a language that aspires to be c (dynamic arrays as a language feature). Ultimately, it doesn't provide anything nearly compelling enough to leave the wide support of the c world.
- brodo 8y ago
  Or kit and nim.
  - protomikron 8y ago
    Levenshtein would argue they differ the same way.
    - bendmorris 8y ago
      I feel like there's a gold rush on three-letter language names. It's going okay so far, but Nit and Zit and Nag had better have some nice features.
      - julia_lang 8y ago
        Apart from Nag, I second.
      - vesche 8y ago
        And I'm just still sittin' here waiting for Jai: https://inductive.no/jai/ https://inductive.no/jai/ Aw snap, the gold rush is real..
sproketboy 8y ago
Cheap Kotlin copy and Kotlin is shit too.
tauk 8y ago
Any examples of games that were created using Kit lang?
- forgotpwd16 8y ago
  It seems it is a very new language, started only few months ago so probably there is nothing created with it yet.
forgotpwd16 8y ago
>designed with game development in mind What design decision and features were made according to that? Basically, what "designed for game development" means? Also checking the commit history, first commit [1] says that it is after a rewrite in Haskell. What was the original language and why made the change? [1]: https://github.com/kitlang/kit/commit/4d3de98f218f2427529ac4af098d8398434ebbef https://github.com/kitlang/kit/commit/4d3de98f218f2427529ac4...
- bendmorris 8y ago
  Hi, creator here. >Basically, what "designed for game development" means? I've been doing a lot of work in Haxe, but have struggled with performance issues due to GC and memory churn. I wanted a lower level language with more control, but without sacrificing the ergonomics and abstractions I'm used to. Term rewriting and implicits are examples of features that let me layer abstractions onto a language but still maintain complete control. >What was the original language and why made the change? It's not up on GitHub, but the prototype was begun in Rust. Ultimately I found I'm much more productive in Haskell and made the switch.
sullyj3 8y ago
This seems to be competing in a similar space to Zig, and especially Jai. How does it compare to them?
- bendmorris 8y ago
  I commented on Zig elsewhere in this thread. Since Jai is unreleased I don't know a lot about it, but their AoS/SoA convertibility was an interesting feature (you can do this in user space in Kit via term rewriting) and I wanted to make it similarly ergonomic to pass around custom allocators.
openbasic 8y ago
I like how clean the lexer is: https://github.com/kitlang/kit/blob/master/src/Kit/Parser/Lexer.x https://github.com/kitlang/kit/blob/master/src/Kit/Parser/Le...
cptwunderlich 8y ago
Interesting language! I saw a "throw" in an example, but I don't see exeptions mentioned anywhere? Woulb be interesting to know why a language with performance focus has exceptions (or are they implemented differently?).
- bendmorris 8y ago
  Good "catch" ;) "throw" in Kit is vestigial; there's no error handling mechanism implemented yet, and I've gone back to the design phase to consider some alternatives.
ionforce 8y ago
Ben, would you cite Scala at all as a source for inspiration?
- bendmorris 8y ago
  Certainly. I don't used Scala much but the inspiration is probably easy to see.
ndh2 8y ago
Ben, could you go a little into detail on what you had in mind with the term rewriting system? The sin/cos example seems a little underwhelming, since these should be evaluated at compile-time in the first place. They seem like a variant on C macros, but without the restriction on function syntax. Maybe one could implement Python's with statement in userland, which is very nice. It also seems to me that you could replace C++ templates, yet you do have generics. How come? What's the difference? My intuition is that ambiguities are at least possible, so what about precedence, which AST term is evaluated first? I'm thinking of some situation where two subtrees match the rule, but you end up with different results depending on which is transformed first. E. g. if you were to define a cross product rule, and apply it to a × b × c. What about infinite loops in rule sets? What about recursion? What about a situation where multiple rules could be applied? Is there any way to debug the transformations? Is that what the `using` scopes are for? If the compiler was to detect ambiguities, that seems pretty expensive, because it would need to match every rule to every subtree, right? This thing seems very, very powerful, I just find it a bit hard to grasp what you can do with it in practice, and what the limitations are. I would be very interested to hear what you ran into so far.
- bendmorris 8y ago
  I think this thread captures a more interesting application of term rewriting: https://twitter.com/bendmorris/status/1041130408463687681 https://twitter.com/bendmorris/status/1041130408463687681 >My intuition is that ambiguities are at least possible, so what about precedence, which AST term is evaluated first? I'm thinking of some situation where two subtrees match the rule, but you end up with different results depending on which is transformed first. E. g. if you were to define a cross product rule, and apply it to a × b × c. This is absolutely a potential issue, and the examples I have up now are quite bad. This is why it's important for rules to be strictly scoped. The only rules that can affect an expression are the ones you've explicitly brought in with a "using" block, or those that are defined for the types you're directly working with. Given the scoping, I think overlapping rule applications will be uncommon in practice. >What about infinite loops in rule sets? What about recursion? There's a sanity limit on the number of times an expression can be rewritten, and it'll show an error in that case which displays the transformations that triggered the limit (including the first, last, and any non-repeating transformations going backward from the last - so it should be very clear.) >Is there any way to debug the transformations? This is definitely an area for improvement. I'm planning to (1) add enforced "rewrite this" metadata that will fail to compile if the expression isn't rewritten, and (2) enable dumping not only the final AST but also all of the transformations that occurred.
rafaelvasco 8y ago
Well designed language! I particularly like that you took great features from Haxe such as Abstracts. So far i didn't see any WTF!?'s in the language syntax, which is rare these days. People these days can get too inventive when designing new languages. I like that you kept things readable (looking at you Rust :) . Nice work!
CyberDildonics 8y ago
How is this better than Clay, other than the fact it is being maintained? http://claylabs.com/clay/ http://claylabs.com/clay/ https://github.com/jckarter/clay/wiki/Avoiding-generic-programming-pitfalls https://github.com/jckarter/clay/wiki/Avoiding-generic-progr...
grok2 8y ago
If it is truly embeddable in a C program (there was some note about using this as a library in a C program), then this would be a fantastic way to augment development of software in C -- it seems to improve on the C programming language. I like the support for generics and type inference and have always wished C had that. The C interop story looks very good too.
dvh 8y ago
This is the first language posted on HN I like. Really nice. How is utf8 supported. What about graphical apps? Android? Web server? How's the performance?
kakashi19 8y ago
Kit looks interesting. But i am going to stick with Haskell.

115 points by BerislavLopac 8y ago

Another programming language. God! I have no idea - what's happening to the world? Are people not skilled enough to propose or send commits to an existing or alternative programming language? There is Rust, Go, Julia, Clojure, and many other... What is the primary reason to create a new programming language?

annywhey 8y ago
Another "too many programming languages" comment. God! I have no idea - what's happening to the world? Are people not skilled enough to evaluate new languages? There are new type systems and static checks, integrated build systems and package managers, backwards-compatibility features, debugging tools... What is the primary reason to complain about new programming languages?
flohofwoe 8y ago
Rust, Go, Swift, etc... are like super-tankers compared to those small "better-C" languages. IMHO, having a number of small languages that can be learned in an afternoon is much better than yet another super-tanker designed by huge consensus-driven committees/communities that try to do everything for everybody.
- carlmr 8y ago
  Rust has safety and zero-cost abstractions at it's core, they provide a by now quite stable interface. You can't just move fast and break things. You need to stabilize at some point or it's impossible to use it in real world projects that are also commitments of a certain kind. And for that stability you need some kind of consensus of what to work on and what not to do. I think the primary value of these new toy languages is they can explore aspects freely that can't just be explored in a more mature language. Sometimes after a concept has proven useful a mature language might be willing to incorporate it. But I wouldn't use them on a serious project, because there will probably be few libraries and maybe no long term support for it.
  - bendmorris 8y ago
    These are valid concerns, particularly stability and long term support. Availability of libraries applies less to Kit or Zig thanks to first-class interoperability with C. I think this is the way forward for small new languages; you can avoid the challenge of creating an entire ecosystem for your language, and just fit it into an existing one.
- eriktate 8y ago
  I'm surprised that you would lump Go in as a "super-tanker" language. I find it incredibly small and simplistic when compared to something like Rust. I think it actually has fewer keywords than C.
  - renox 8y ago
    Go the language OK but Go rely on a GC which required lots of work..
tragomaskhalos 8y ago
Suspect that in the majority of cases it's a bit like people inventing their own (human) constructed language - it's an interesting intellectual exercise in its own right and allows the inventor to indulge in a bit of wish fulfilment by emphasising features that they personally value. As in the human conlang case, it would be alarming or bizarre if the inventor genuinely expected others to start coding in their language, especially if it has no compelling features that are not found elsewhere: although Perl, C++, Rust and others came primarily from motivated individuals "scratching an itch", those langs were able to flourish because they fill(ed) an empty evolutionary niche. What I do find peculiar is other people then piling in with all sorts of suggestions for enhancements and tweaks that imply that the particular hobby language in question does have a legit future out in the field.
coldtea 8y ago
>Are people not skilled enough to propose or send commits to an existing or alternative programming language? How would those "alternative programming languages" you propose have been created if people followed your "advice"? We'd still be sending patches to C and C++ or perhaps Algol? >What is the primary reason to create a new programming language? 1) Because you feel like it and you don't need to have approval for anybody to do so. 2) Because you want to explore some particular syntax/semantics combination other languages don't offer. 3) As a training exercise. 4) To cover some very specific needs you have, and don't like how other languages do it. 5) To introduce some new ideas into PL design, which might or might not be adopted by users or by a more mainstream language.
- eksemplar 8y ago
  C++ had a purpose though, to create object oriented C. A lot of these modern languages seem to be mainly made because someone could. With so many there is also a very low chance of any of them actually picking up because the useless ones drown out the C++es. I think people should do what they want though. If you want to make a programming language you should, just don’t expect everyone to view your endeavors as useful. As far as your fifth point goes, new languages aren’t a good way to influence programming in general. Stuff like lambdas weren’t born in some hipster language, they came from JavaScript. Because if you want to influence, you have to make sure people actually see your stuff. That being said. Making a PL language is a much better use of your time than whining on HN.
  - flohofwoe 8y ago
    Many of those new languages are created because C++ failed to improve C in the areas that really matter: http://esr.ibiblio.org/?p=7724 http://esr.ibiblio.org/?p=7724
    - pjmlp 8y ago
      Actually it improved, what C++ compilers cannot prevent is for people to write C code with a C++ compiler, beyond outlawing it as bad practice. Copy-paste compatibility with C is a burden on modern computing, but it was also what contributed to C++'s adoption during the early 90's.
efficax 8y ago
I also find the march of new languages a little exhausting. But I handle that by just taking a glance at them and moving on. Kit never has to trouble me again and I'll have already forgotten it by the time I hit reply here. And my life will go on.
otabdeveloper1 8y ago
> What is the primary reason to create a new programming language? The reason is that creating a new programming language is easier than learning C++. For this same reason none of these languages will ever amount to anything useful. If you have the patience and foresight to bring a new programming language to fruition, then you have the patience and foresight to learn C++. You grow up and start programming in a real language.
- bendmorris 8y ago
  I, uh...I know a little C++ :) I like to think that when I'm writing Kit, I'm writing C, so I am writing in a "real language." Total interop, no real drawbacks.
bendmorris 8y ago
>Are people not skilled enough to propose or send commits to an existing or alternative programming language? I'll just comment on this part. I'm a contributor to Haxe (not so mainstream perhaps but more so than Kit.) Kit was a chance to try out some features that don't fit in well to Haxe (and in fact I did propose several of these features as additions to Haxe, and they were explicitly rejected.) Sometimes the answer really is to write a new language, because language simplicity is still important and one language can't be everything to everyone. And of course, Haxe wouldn't exist if its creator hadn't been unsatisfied with existing languages at the time...
AndyKelley 8y ago
> Oh shit everything is already made guess I'll watch Netflix while I wait to die have fun with that

annywhey 8y ago

This looks like it takes influences variously from Haxe, Rust, and Haskell, which are all great in my book. But the first thing that crossed my mind was, "could it compile to other languages besides C?" The reason being that I think the way to really move up the baseline is to take another page from Haxe and aim for cross-compatibility between different systems languages, becoming a "language that unites them all". So that could mean relatively new and hip ones like Rust, D or Zig, or older ones like Pascal(Delphi), Fortran, Cobol... And those are niches relative to C, but they're nearly unserved niches AFAIK.

flohofwoe 8y ago
AFAIK languages "compile to C" mainly because they use C as an intermediate representation and the C compiler as the last stage of the compile/link process, so kitlang itself doesn't need to support code generation for various CPUs, and also doesn't need to implement an LLVM frontend. Instead it uses the target platform's C compiler, which is a lot less work but has basically no downsides. Also the C IR code might make it easier to interop with other languages, since C is basically the 'lingua franca' that all other languages can talk to in some form.
- kibwen 8y ago
  > Instead it uses the target platform's C compiler, which is a lot less work but has basically no downsides. The downsides of leveraging a platform's given C compiler as your backend is that now you'll be spending a large chunk of time learning the hard way about all the various incompatibilities in C compilers, and adding workarounds in your frontend for the otherwise-unpatchable behavior encountered in every old version of every major compiler on every platform you wish to support. Conversely, the advantage of using a single known backend is that you can automatically know what code your users are running when they submit a bug report, and you can fork and ship the patch yourself rather than trying to convince an upstream C compiler to accept the patch, then convince the upstream distro to ship the new version of the compiler, then convincing all your users to update their platform C compiler. Walter Bright concurs: https://news.ycombinator.com/item?id=16195031 https://news.ycombinator.com/item?id=16195031 Kit may have an easier time of it if it's intended only for games, since that narrows down its supported target platforms substantially. The harsh truth is that most game devs only care about one platform (Windows) and one toolchain (MSVC), so at least it can tailor its output to appease MSVC specifically.

bitmadness 8y ago

This looks amazing! Does it support parallel/multicore programming?

xtrapolate 8y ago

> "Memory management in Kit is manual (no automatic garbage collection), with some convenience features to make this easier." I was curious, but there aren't any examples of this on https://www.kitlang.org/examples.html https://www.kitlang.org/examples.html

dvfjsdhgfv 8y ago

Anyone is actually using it? If so, could you compare it to Nim that also compiles to C?

rishav_sharan 8y ago

I am far more interested in the comparison between kit and Zig.

forgotpwd16 8y ago
Also Myrddin and C2 seem to target a similar niche.
- earenndil 8y ago
  I've written about c2 before. It has some things that might be nice to have in c (header files, remove ->), and some things that make Zero sense to have in a language that aspires to be c (dynamic arrays as a language feature). Ultimately, it doesn't provide anything nearly compelling enough to leave the wide support of the c world.
brodo 8y ago
Or kit and nim.
- protomikron 8y ago
  Levenshtein would argue they differ the same way.
  - bendmorris 8y ago
    I feel like there's a gold rush on three-letter language names. It's going okay so far, but Nit and Zit and Nag had better have some nice features.
    - julia_lang 8y ago
      Apart from Nag, I second.
    - vesche 8y ago
      And I'm just still sittin' here waiting for Jai: https://inductive.no/jai/ https://inductive.no/jai/ Aw snap, the gold rush is real..

sproketboy 8y ago

Cheap Kotlin copy and Kotlin is shit too.

tauk 8y ago

Any examples of games that were created using Kit lang?

forgotpwd16 8y ago
It seems it is a very new language, started only few months ago so probably there is nothing created with it yet.

forgotpwd16 8y ago

>designed with game development in mind What design decision and features were made according to that? Basically, what "designed for game development" means? Also checking the commit history, first commit [1] says that it is after a rewrite in Haskell. What was the original language and why made the change? [1]: https://github.com/kitlang/kit/commit/4d3de98f218f2427529ac4af098d8398434ebbef https://github.com/kitlang/kit/commit/4d3de98f218f2427529ac4...

bendmorris 8y ago
Hi, creator here. >Basically, what "designed for game development" means? I've been doing a lot of work in Haxe, but have struggled with performance issues due to GC and memory churn. I wanted a lower level language with more control, but without sacrificing the ergonomics and abstractions I'm used to. Term rewriting and implicits are examples of features that let me layer abstractions onto a language but still maintain complete control. >What was the original language and why made the change? It's not up on GitHub, but the prototype was begun in Rust. Ultimately I found I'm much more productive in Haskell and made the switch.

sullyj3 8y ago

This seems to be competing in a similar space to Zig, and especially Jai. How does it compare to them?

bendmorris 8y ago
I commented on Zig elsewhere in this thread. Since Jai is unreleased I don't know a lot about it, but their AoS/SoA convertibility was an interesting feature (you can do this in user space in Kit via term rewriting) and I wanted to make it similarly ergonomic to pass around custom allocators.

openbasic 8y ago

I like how clean the lexer is: https://github.com/kitlang/kit/blob/master/src/Kit/Parser/Lexer.x https://github.com/kitlang/kit/blob/master/src/Kit/Parser/Le...

cptwunderlich 8y ago

Interesting language! I saw a "throw" in an example, but I don't see exeptions mentioned anywhere? Woulb be interesting to know why a language with performance focus has exceptions (or are they implemented differently?).

bendmorris 8y ago
Good "catch" ;) "throw" in Kit is vestigial; there's no error handling mechanism implemented yet, and I've gone back to the design phase to consider some alternatives.

ionforce 8y ago

Ben, would you cite Scala at all as a source for inspiration?

bendmorris 8y ago
Certainly. I don't used Scala much but the inspiration is probably easy to see.

ndh2 8y ago

Ben, could you go a little into detail on what you had in mind with the term rewriting system? The sin/cos example seems a little underwhelming, since these should be evaluated at compile-time in the first place. They seem like a variant on C macros, but without the restriction on function syntax. Maybe one could implement Python's with statement in userland, which is very nice. It also seems to me that you could replace C++ templates, yet you do have generics. How come? What's the difference? My intuition is that ambiguities are at least possible, so what about precedence, which AST term is evaluated first? I'm thinking of some situation where two subtrees match the rule, but you end up with different results depending on which is transformed first. E. g. if you were to define a cross product rule, and apply it to a × b × c. What about infinite loops in rule sets? What about recursion? What about a situation where multiple rules could be applied? Is there any way to debug the transformations? Is that what the `using` scopes are for? If the compiler was to detect ambiguities, that seems pretty expensive, because it would need to match every rule to every subtree, right? This thing seems very, very powerful, I just find it a bit hard to grasp what you can do with it in practice, and what the limitations are. I would be very interested to hear what you ran into so far.

bendmorris 8y ago
I think this thread captures a more interesting application of term rewriting: https://twitter.com/bendmorris/status/1041130408463687681 https://twitter.com/bendmorris/status/1041130408463687681 >My intuition is that ambiguities are at least possible, so what about precedence, which AST term is evaluated first? I'm thinking of some situation where two subtrees match the rule, but you end up with different results depending on which is transformed first. E. g. if you were to define a cross product rule, and apply it to a × b × c. This is absolutely a potential issue, and the examples I have up now are quite bad. This is why it's important for rules to be strictly scoped. The only rules that can affect an expression are the ones you've explicitly brought in with a "using" block, or those that are defined for the types you're directly working with. Given the scoping, I think overlapping rule applications will be uncommon in practice. >What about infinite loops in rule sets? What about recursion? There's a sanity limit on the number of times an expression can be rewritten, and it'll show an error in that case which displays the transformations that triggered the limit (including the first, last, and any non-repeating transformations going backward from the last - so it should be very clear.) >Is there any way to debug the transformations? This is definitely an area for improvement. I'm planning to (1) add enforced "rewrite this" metadata that will fail to compile if the expression isn't rewritten, and (2) enable dumping not only the final AST but also all of the transformations that occurred.

rafaelvasco 8y ago

Well designed language! I particularly like that you took great features from Haxe such as Abstracts. So far i didn't see any WTF!?'s in the language syntax, which is rare these days. People these days can get too inventive when designing new languages. I like that you kept things readable (looking at you Rust :) . Nice work!

CyberDildonics 8y ago

How is this better than Clay, other than the fact it is being maintained? http://claylabs.com/clay/ http://claylabs.com/clay/ https://github.com/jckarter/clay/wiki/Avoiding-generic-programming-pitfalls https://github.com/jckarter/clay/wiki/Avoiding-generic-progr...

grok2 8y ago

If it is truly embeddable in a C program (there was some note about using this as a library in a C program), then this would be a fantastic way to augment development of software in C -- it seems to improve on the C programming language. I like the support for generics and type inference and have always wished C had that. The C interop story looks very good too.

dvh 8y ago

This is the first language posted on HN I like. Really nice. How is utf8 supported. What about graphical apps? Android? Web server? How's the performance?

kakashi19 8y ago

Kit looks interesting. But i am going to stick with Haskell.