[btbytes]

Not surprisingly, it is J [1], an APL dialect.

[1] https://www.jsoftware.com/

[eimrine]

I knew it without the reading. But having each system call in 2 versions not even closely related to each other (monadic/diadic) requires me to have a hard time doing learning. I very appreciate this language for shortness but this kind of shortness might annoy.