So I have this bit of APL code: `{⍵, +/¯2↑⍵}0 1`, which I can tacitly rewrite to `(⊢,(+/¯2↑⊢))0 1`. They both produce the correct result of `0 1 1`
However, if I try to do the same in J: `{{ y, +/ _2{.y }} 0 1` --> `([,(+/_2{.[)) 0 1` I get completely different results between the two versions.
What am I doing wrong/misunderstanding here?