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The Monkey Programming Language

monkeylang.org

160 pointsazhenley34 comments

This is remarkably similar to the Lox language and the book Crafting Interpreters[1] by Bob Nystrom, which I only just read about on HN like two days ago. (Edit: one major difference is, Nystrom's book is free.)

[1] http://www.craftinginterpreters.com

I had the same thought while reading through this site! I've started working through Crafting Interpreters a few weeks ago. I have been loving it. I'll generally read a chapter one evening, and then write the code from it the next day and re-read bits of the chapter to clarify the code. It's been really enjoyable.

One thing I want to do next is to try and implement the tree-walking interpreter again in another language (probably F# in my case) and maybe share it if I finished it up. This site is basically a concrete version of that small thought in my head.

Funny how things work out!

One is Java/recusrive descent, the other is Go/Pratt -- in the Go interpreter book, Thorsten explicity mentions Bob's Pratt parser tutorial as the go-to resource for explaining how Pratt parsers work. Both books are very good as practical guides to language implementation -- if Bob ever charged for Crafting Interpreters I'd gladly pay.

Bit of bait-and-switch here: thought I was learning about a new programming language when it's more a pitch for books about making programming languages. Creative advertising on the part of the author though!

A little bit = but personally happy to see a website for the language - there are a lot of implementations out there now ,so its good to have a source point.

If you have not read the books they are a really good practical introductions to building interpreters and compilers.

Thorsten Ball very recently gave an interview on Software Engineering Radio [1] where he discusses the books and the language and his thinking on each.

[1] https://www.se-radio.net/2019/05/365-thorsten-ball-on-buildi...

I thought this was Mark Sibly's Monkey language.

[1] http://monkeycoder.co.nz/

I initially thought it was about the Monkey C language: https://developer.garmin.com/connect-iq/monkey-c/

As a Monkey C developer, I'd say Monkey C is a better example of how not to design a programming language.

Making it OO on a system with so little memory available to apps was an especially weird basic decision, I thought. There were cases where memory use was unavoidably bloated for no good reason, and meanwhile there wasn't enough space to actually do any architecture-astronaut OO stuff.

I wished the whole time they'd just given me a somewhat locked-down C, and I'm only a C-dabbler so that's not a preference I'd have due to great familiarity or anything.

It was overall somewhat more unpleasant, but less weird, than writing code for Roku. Most of the Roku weirdness was just because they had some new very-much-halfassed XML programming system you had to use for new apps at the time, which forced you to define public interfaces for objects in XML for no good reason while doing the actual work in Brightscript, which isn't gonna win any language design awards ever but is at least usable. Plus it's obscure so figuring all that out was tons of fun.

currently working my way through this book, and implementing it in C++ - very good book! I'm really enjoying it.

I was looking for this and didn't realize it. I'm designing a fantasy console and wanted to include a modern-syntax, small, interpreted language that has many independent implementations - a new BASIC or Pascal. Lua comes close to this but attention is really centered around the PUC-Rio and LuaJIT implementations and not on being easily reimplemented, and every "classic" option one might think of(including Lisps and Forths) falls a bit outside today's mainstream.

I may be getting the book soon...

I would argue for a Lisp. If you’re asking the user to use a language they’re not familiar with, it might as well be one that will expand their horizons, despite the potentially offputting syntax. It would be really cool if you added a key that switched from s-expressions to Sweet expressions[0] (and vice-versa). Forth is painful to use for anything more than a toy and no matter what language you choose it would be awesome to see a live-updating (graphical?) REPL.

[0] https://readable.sourceforge.io

Expanding PL horizons is not a goal for this project. The goal for this specific usercode layer(of which there are four: WASM bytecode, the I/O memory map, the lower level operating system language, and the higher level interpreted language) is to achieve a mix of sustainability and familiarity. A language defined by a book explaining its implementation, while also being in the "looks-like-an-Algol" ballpark, falls very close to that mark.

If you want a Lisp, it's possible, just rewrite the OS layer.

Also consider looking at SOM - nine implementations http://som-st.github.io.

Have you seen Wren?

https://github.com/wren-lang/wren

Wren is small, and the language is aesthetically appealing, but it's small in the specific way of its C implementation being a small SLOC while implementing nifty features, not "anyone could study this codebase and port it to a new environment". It relies extensively on the preprocessor.

(I speak from experience.)

Racket has an embedded shell language, Rash

https://docs.racket-lang.org/rash/index.html

Much more thought needs to be given to the AST and the public API(s). See here: https://github.com/chrismsimpson/Meta.

If it's going to be 'the final system' there really has to be legion compelling reason to switch. I just don't see it.

Also, and I honestly mean no offence, but do we really want to call it Monkey? It's a tad childish. We're going to be asking Governments, Banks, public services etc. to being using this thing.

You're telling me you wouldn't use NSSM? Its awesome.

No. For the non tech literate, this will become a fundamental issue of safety.

Non tech literate shouldn't be making these choices. This is why they'll miss out on Cockroach DB, eh?

Umm.. says who? You?

This is another language whose syntax is similar to Rust's. I wonder why the author chose it, in spite of its Go heritage.

Also yet another language called 'Monkey'.

There's already Monkey C used to develop for Garmin devices, and the Monkey/MonkeyX/Monkey2 family by Mark Sibly (of Amiga Blitz Basic fame).

I originally thought this post was related to Mark Sibly's trans-compiler, which I used in the past and enjoyed quite a bit: http://monkeycoder.co.nz/

I'd say it's more similar to Javascript. In fact all of the examples are valid JS if you replace `fn` with `function`. (Although JS doesn't have implicit returns.)

At a guess, the author chose the syntax because it's familiar and easy to parse. Go's syntax is... eccentric where it differs from typical C-style languages.

Author here. Yes, that's exactly right. I wanted to show how to write a parser/interpreter for something that you encounter every day. JavaScript-like syntax, with curly braces and `if`/`else` is just that.

Seems very similar to ES6

It seems every new C-like has Rust's expressive if/else and implicit returns. And why not? They're strict improvements on the syntax. Makes me wonder why they didn't become prevalent many years ago.

Both of these things were invented by Lisp. The reason C didn't include them was because C and its ancestors was designed to be easy to write a parser for (well, "relatively" anyway, it's not exactly as barebones as sexps) and to be usable with a preprocessor macro system, so you end up with a language designed with a lot of syntactic cruft (braces, semicolons, ternaries, etc.) meant as aids to compiler authors.

> you end up with a language designed with a lot of syntactic cruft (braces, semicolons, ternaries, etc.) meant as aids to compiler authors.

Many of those are not just for the easiness of implementation but also for the quality of partial parsing, frequently required for today's compilers. I do agree that they are not intentionally designed in that way.

Yes yes, Lisp invented everything, I know. I was talking about the fact that (to the best of my knowledge) Rust introduced them to the C-like syntax world.

Clojure version, any?

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