J: From C to C++20

⚠️⚠️⚠️ THIS PROJECT IS ON PAUSE AT THE MOMENT ⚠️⚠️⚠️

J is an array programming language created by Ken Iverson and Roger Hui (see image below).

This is a fork of jsoftware/jsource and we will be porting it to C++20.

Motivation

The motivation for this is to learn about how Ken Iverson / Roger Hui implemented the J language (and similarly APL as J is the successor to APL). The end goal is to learn as much as possible.

Try J

If you would like to try J without building from source, check out this site: http://tryj.freeddns.org/

Goals

• Reduce complexity of build options
• Compile with GCC 10+
• Compile with Clang 11+
• Remove all (most) of the macros
• Clang-format the code base
• Clang-tidy the code base
• Set up CI (Buildkite)
• Set up Code Coverage
• Set up badges
• Get both build / tests running in parallel
  • Parallel build (for free off of zhihaoy branch)
  • Parallel tests
• Monitor compile & run time perf while refactoring

Non-Codebase Goals

• Learn to not use mouse

Comparison of Languages

Calculating the first 10 odd numbers:

Language	Code	Runnable Link
J	1+2*i.10	j playground
APL	¯1+2×⍳10	TryAPL
R	-1+2*seq(10)
Python	[1 + 2 * i for i in range(10)]	Godbolt
Haskell	map (1+) $ map (2*) [0..9]	OneCompiler
Haskell	map ((+1) . (*2)) [0..9]	OneCompiler
Haskell	take 10 [1,3..]	OneCompiler
C++	transform(iota(0, 10), [](auto e) { return e * 2 + 1; })	Godbolt
C#	Enumerable.Range(0, 10).Select((int i) => { return i * 2 + 1; })
Java	IntStream.range(0, 10).map(x -> x * 2 + 1).toArray();
Ruby	(0..9).map { |i| i * 2 + 1 }	Try It Online

Getting started & Building:

For building this repository, please see CONTRIBUTING.md.

Image of Ken Iverson and Roger Hui