[llasram]

I've recently been learning J to try something different, and have worked through the first 60-odd Project Euler problems using it.

My current assessment is that J combines the powerful computational primitives of a language designed by a brilliant applied mathematician with the FFI & I/O interfaces of a language designed by a brilliant applied mathematician. Writing purely algorithmic code feels like writing executable math in ASCII. Writing code which needs to interact with the outside system feels like programming an 80’s 8-bit microcomputer in BASIC.

I have not yet learned APL or K, so I cannot yet compare and contrast.

* Edited to add: most useful for me so far has been the book J for C Programmers bundled with the official documentation. It mostly takes the tack of expecting that you already know how to program and want to know how to do certain things you can do in other languages in J. Additionally the final section on "tacit programming" includes some details on the implementation which made some of the more obscure behaviors of the language more clear.