[rscho]

> `1 + 1` is not an addition of two scalars, but instead of two arrays of length 1

I think that's true of (Dyalog) APL, but not of J [1]. APL follows the nested array model (that you describe), while J follows the flat array model that does have true scalars.

[1] https://aplwiki.com/wiki/Array_model#Flat_array_theory

[dzaima]

AFAIK, J considers `1` to be an array - `L. 1` and `L. 1 2` both give 0 (`L. (1;2)` gives 1).

APL's simple scalar numbers are much more like regular numbers in non-array languages.