There are currently two active BQN implementations: the self-hosted one in this repository, and the independent dzaima/BQN. Neither is entirely complete but they are quite capable for pure programming tasks (say, implementing a compiler). For scripting, only dzaima/BQN has the required I/O such as file functions. I tend to develop parts of applications in the online REPL and move to dzaima/BQN scripts in order to run them.
The online REPL is here. The file docs/bqn.js is zero-dependency Javascript, and can be loaded from HTML or Node.js. It can also be called directly from the command line (using Node); in this case each argument is evaluated as BQN code and the result is printed. This notebook shows how to run it in an Observable notebook.
The version of BQN in this repository is implemented mainly in BQN itself—the compiler is entirely self-hosted, while the runtime is built from a small number of starting functions using preprocessed BQN. It completely supports the core language except for block headers and multiple body syntax, and a few cases of structural Under (⌾). The Javascript-based compiler is also slow, taking about 0.05 seconds plus 1 second per kilobyte of source (this is purely due to the slow runtime, as dzaima+reference achieves 1ms/kB with the same compiler once warmed up).
Because self-hosted BQN requires only a simple virtual machine to run, it is fairly easy to embed it in another programming language by implementing this virtual machine. The way data is represented is part of the VM implementation: it can use native arrays or a custom data structure, depending on what the language supports. An initial implementation will be very slow, but can be improved by replacing functions from the BQN-based runtime with native code. As the VM system can be hard to work with if you're not familiar with it, I advise you to contact me to discuss this option it you are interested.
In progress VMs are CBQN in C, and ebqn in Erlang. Although both of these work (can compile and run code; only missing some fill support in CBQN), neither is considered useful for any purpose yet. CBQN is likely to become the main high-performance BQN implementation but is currently only a few times faster than Javascript and has an interface that's only useful for testing. ebqn is extremely slow—hours to compile.
dzaima/BQN is an implementation in Java created by modifying the existing dzaima/APL. It should be easy to run on desktop Linux and Android. It is still in development and has almost complete syntax support but incomplete primitive support: major missing functionality is dyadic Depth (⚇), Windows (↕), and many cases of set functions (⊐⊒∊⍷, mostly with rank >1).
In this repository and elsewhere, dzaima/BQN scripts are called with #! /usr/bin/env dbqn. This requires an executable file dbqn somewhere in your path with the following contents:
#! /bin/bash java -jar /path/to/dzaima/BQN/BQN.jar "$@"
If compiled with Native Image, nBQN can be used directly instead.
This repository contains a dzaima/BQN script dzref that fills in gaps in primitive support with BQN implementations. dzaima/BQN has good enough primitive support that I now almost never use this, but it's still needed for the website generator md.bqn. The command-line arguments are a script to run and followed by the •args to supply to it.
BQN2NGN is a prototype implementation in Javascript build to experiment with the langauge, which is now abandoned.