It is an excellent book and one of the canonical texts on the subject. My only suggestion for the "Lox" language would be to include an implementation of arrays, and preferably also hash/dict arrays. Other than that, the book contains everything you need to know about implementing a programming language.
I understand. I wasn't a Java person when I read that book, yet I still prefer Java over more esoteric options. If Golang is easier for you to understand (no OOP), then I can recommend this one:
Wren, the topic of the post, is positioned as a descendant of Smalltalk, the most OOP language of them all. The author clearly finds the OOP paradigm important.
This is awesome. Thank you for sharing. I have been working on a small interpreted language for shell scripts with lots of help from Claude Code. The main idea is to automatically generate the cli interface for the scripts based on function definitions. However, I'm far from a programming languages expert, so I've been a bit hesitant to share my work. Going to give this book a read this week to see how far I am. Thank you!
I was working on a custom runtime for minimal wasm apps recently. I didn't want to have to write all apps in C or Rust, so I went looking for tiny scripting languages. Lua is pretty small, but I wasn't able to get it to compile to wasm IIRC due to POSIX dependencies. This turned out to be quite easy with Wren[0].
That's unusual that you struggled to build Lua. Lua is primarily C89, and used on non-POSIX microcontrollers for example. There are some optional bits of the standard library you would have to leave out - module loading uses dlopen(). This is done simply by defining the right feature macros for your target environment: https://www.lua.org/source/5.4/luaconf.h.html
Wow, I really went into a rabbithole after opening up your hackernews profile seeing indiebits and remembering my time scouring your github awesome tunneling page and then I went to discourse forum and somehow found new resources about self hosting and saw yunohost and others as well all in matter of minutes.
Thank you for your service in self-hosting. I had so much fun trying to break nats with awesome tunneling projects and I even created my own but it actually requires a custom patch of ssh with pinggy to work without nat (let me know if you are interested, as I had discovered this a year ago but I just am a little lazy haha)
I have created only one issue on the awesome tunneling but let me tell you some of them don't work in nat's/broke
Just created the bearblog post, not sure why the name but just wanted to say thank you and wanted to share any knowledge I have in the process as well to strengthen the hacking/tinkering community. Thanks once again
Also its just a bit of a coincidence that we are talking on a wren page as I was literally reading about wren once again and playing with it just yesterday and joined their discord server yesterday or day before that to tinker with it. Wren is really elegant and I feel like I want to write more software which integrates it instead of lua as a thought experiment as well and wasm seems a cool idea too in that regards.
This seems like a nice alternative to Lua. I've always liked embedding Lua in other software, but I confess I have never really liked Lua as a language.
Yeah, Lua's implementation is fantastic - but the language is "quirky" at best.
Wren looks a bit more orthodox, although it's heavily built around class-based OOP - you can't even define and call a top-level function without extra syntax to (1) turn it into an object, and (2) call one of that object's methods:
var sayHello = Fn.new { System.print("hello") }
sayHello.call() //> hello
I really like the sound of Wren, but you may also want to look into Squirrel, it's basically Lua re-imagined/reimplemented but without all the Lua quirks and with C-style syntax (but it still has optional lua-style prototypes, which means it ends up very similar to Javascript). Its embedding API is largely a copy of Lua's. There is also an active fork called Quirrel that makes the language more like Python.
There are loads of scripting languages but very few of them have an embedding API as powerful as Lua or Squirrel's. (My benchmarks: what's the overhead of a userdata pointer? Is there a proper debug API? Can you suspend a co-routine from inside a called C function? Very few languages even have coroutines.) Last I looked at it years ago, Wren was one of the best.
Of course, the most featureful embedding API of all belongs to LuaJIT.
This looks super cool up until I got to the point where it says inherited classes don’t share the same metatable. Meaning if you want to provide the same method on your inherited classes, you have to write the same thing and do a super.method() which means a lot of work if you’re into OO design so I’m not sure if classes is the right construct here. Am I wrong or did I miss something from the documentation? Other than that it looks like fun to use as an embedded scripting engine.
you probably meant metaclass and according to the doc classes inheritance don't have surprising behaviors. And about the metaclass not being inherited here are the implication:
...In more prosaic terms, this means that static methods are not inherited.
I think I read that Wren's creator deliberately avoided "the metaclass hierarchy matches the class hierarchy" (as used in Smalltalk and taken to an extreme in Ruby) because the authors of Smalltalk have come to regret that design?
I'd be interested to hear more details about the issues with that approach. I've not had any problems with it, and occasionally found it useful. For example, in one situation I needed a hierarchy of static constructors that matched the hierarchy of instance constructors.
Edit: Here's the quote I was remembering:
> My hunch is that we don't want metaclass inheritance. From talking to a few old Smalltalkers, they generally consider it a mistake there. Also, Java, C++, C#, etc. have semantics more similar to not allowing metaclass inheritance (in other words, static methods aren't inherited), and it seems to work well there.
I would love to replace JS as the scripting language in one of my native macOS apps and I wonder if Wren would be suitable.
The two biggest questions I’d have are:
1) how easy it would be to bridge Obj-C objects to Wren-space and vice versa (a big win of using JavascriptCore)
2) how easy would it be to implement script debugging? This is not exactly a strength of Javascript core but it is at least possible by connecting the Safari web inspector.
There’s lots I don’t like about JS and JSCore but i’ve yet to find a better alternative.
Reminder the creator of Wren wrote the awesome Crafting Interpreters book [0].
[0] https://craftinginterpreters.com/
It is an excellent book and one of the canonical texts on the subject. My only suggestion for the "Lox" language would be to include an implementation of arrays, and preferably also hash/dict arrays. Other than that, the book contains everything you need to know about implementing a programming language.
I wish he would have used C for everything. You need to buyin into Java's whole OOP thing, which I am not a fan of.
I understand. I wasn't a Java person when I read that book, yet I still prefer Java over more esoteric options. If Golang is easier for you to understand (no OOP), then I can recommend this one:
https://interpreterbook.com/
BTW, I'm not the author of either of those books, but I have read both of them.
Wren, the topic of the post, is positioned as a descendant of Smalltalk, the most OOP language of them all. The author clearly finds the OOP paradigm important.
and he wrote Game Programming Patterns [0]
[0] https://gameprogrammingpatterns.com/
Knowing this is the author makes me 1000% more interested in Wren. What a great book!
This is awesome. Thank you for sharing. I have been working on a small interpreted language for shell scripts with lots of help from Claude Code. The main idea is to automatically generate the cli interface for the scripts based on function definitions. However, I'm far from a programming languages expert, so I've been a bit hesitant to share my work. Going to give this book a read this week to see how far I am. Thank you!
Take a look at how Nushell does this, it's quite neat: https://www.nushell.sh/book/custom_commands.html#documenting...
That's excellent. Somewhat similar to the syntax I went with, but most likely much better implemented. I'm going to give it a go. Thank you!
Is Bob still involved (in Wren)?
I thought his focus was Dart these days given being employed by Google.
I was working on a custom runtime for minimal wasm apps recently. I didn't want to have to write all apps in C or Rust, so I went looking for tiny scripting languages. Lua is pretty small, but I wasn't able to get it to compile to wasm IIRC due to POSIX dependencies. This turned out to be quite easy with Wren[0].
[0]: https://github.com/wren-lang/wren/issues/1199
That's unusual that you struggled to build Lua. Lua is primarily C89, and used on non-POSIX microcontrollers for example. There are some optional bits of the standard library you would have to leave out - module loading uses dlopen(). This is done simply by defining the right feature macros for your target environment: https://www.lua.org/source/5.4/luaconf.h.html
You may also be interested in this project: https://github.com/fengari-lua/fengari
I've used fengari and it's a great option for lua in the browser, but it is quite slow.
Wow, I really went into a rabbithole after opening up your hackernews profile seeing indiebits and remembering my time scouring your github awesome tunneling page and then I went to discourse forum and somehow found new resources about self hosting and saw yunohost and others as well all in matter of minutes.
Thank you for your service in self-hosting. I had so much fun trying to break nats with awesome tunneling projects and I even created my own but it actually requires a custom patch of ssh with pinggy to work without nat (let me know if you are interested, as I had discovered this a year ago but I just am a little lazy haha)
I have created only one issue on the awesome tunneling but let me tell you some of them don't work in nat's/broke
https://freedomhascost.bearblog.dev/
Just created the bearblog post, not sure why the name but just wanted to say thank you and wanted to share any knowledge I have in the process as well to strengthen the hacking/tinkering community. Thanks once again
Also its just a bit of a coincidence that we are talking on a wren page as I was literally reading about wren once again and playing with it just yesterday and joined their discord server yesterday or day before that to tinker with it. Wren is really elegant and I feel like I want to write more software which integrates it instead of lua as a thought experiment as well and wasm seems a cool idea too in that regards.
This seems like a nice alternative to Lua. I've always liked embedding Lua in other software, but I confess I have never really liked Lua as a language.
Yeah, Lua's implementation is fantastic - but the language is "quirky" at best.
Wren looks a bit more orthodox, although it's heavily built around class-based OOP - you can't even define and call a top-level function without extra syntax to (1) turn it into an object, and (2) call one of that object's methods:
I really like the sound of Wren, but you may also want to look into Squirrel, it's basically Lua re-imagined/reimplemented but without all the Lua quirks and with C-style syntax (but it still has optional lua-style prototypes, which means it ends up very similar to Javascript). Its embedding API is largely a copy of Lua's. There is also an active fork called Quirrel that makes the language more like Python.
There are loads of scripting languages but very few of them have an embedding API as powerful as Lua or Squirrel's. (My benchmarks: what's the overhead of a userdata pointer? Is there a proper debug API? Can you suspend a co-routine from inside a called C function? Very few languages even have coroutines.) Last I looked at it years ago, Wren was one of the best. Of course, the most featureful embedding API of all belongs to LuaJIT.
Popular in 2022 (301 points, 130 comments) https://news.ycombinator.com/item?id=32631553
2020 (122 points, 54 comments) https://news.ycombinator.com/item?id=23660464
Wren ties with Phix for most tasks done on Rosetta Code [1].
[1] https://rosettacode.org/wiki/Rosetta_Code/Rank_languages_by_...
Wow that’s an interesting list. Sorta of surprising with Raku beating out Perl. Nim is also in the top 10, nice!
Wren is the primary scripting language for the Luxe engine, currently in development: https://luxeengine.com/
This looks super cool up until I got to the point where it says inherited classes don’t share the same metatable. Meaning if you want to provide the same method on your inherited classes, you have to write the same thing and do a super.method() which means a lot of work if you’re into OO design so I’m not sure if classes is the right construct here. Am I wrong or did I miss something from the documentation? Other than that it looks like fun to use as an embedded scripting engine.
you probably meant metaclass and according to the doc classes inheritance don't have surprising behaviors. And about the metaclass not being inherited here are the implication:
I think I read that Wren's creator deliberately avoided "the metaclass hierarchy matches the class hierarchy" (as used in Smalltalk and taken to an extreme in Ruby) because the authors of Smalltalk have come to regret that design?
I'd be interested to hear more details about the issues with that approach. I've not had any problems with it, and occasionally found it useful. For example, in one situation I needed a hierarchy of static constructors that matched the hierarchy of instance constructors.
Edit: Here's the quote I was remembering:
> My hunch is that we don't want metaclass inheritance. From talking to a few old Smalltalkers, they generally consider it a mistake there. Also, Java, C++, C#, etc. have semantics more similar to not allowing metaclass inheritance (in other words, static methods aren't inherited), and it seems to work well there.
https://groups.google.com/g/wren-lang/c/LkKg51fEUg4/m/0GOK0P...
I would love to replace JS as the scripting language in one of my native macOS apps and I wonder if Wren would be suitable.
The two biggest questions I’d have are:
1) how easy it would be to bridge Obj-C objects to Wren-space and vice versa (a big win of using JavascriptCore) 2) how easy would it be to implement script debugging? This is not exactly a strength of Javascript core but it is at least possible by connecting the Safari web inspector.
There’s lots I don’t like about JS and JSCore but i’ve yet to find a better alternative.
Looks very nice! Erlang's concurrency isn't 'cooperative' though - it has a scheduler, so even a runaway process won't bog down the whole system.
2016