Does applying the Rank operator to a dyadic function preserve its argument order in Dyalog APL?
0 reputation · 15 Jul 2025, 20:46 UTC
When using the Rank operator (⍤) to apply a dyadic primitive such as − to a specific axis of a higher‑dimensional array, the goal is to determine whether the function receives its left and right arguments in the same order as when the function is used without Rank.
APL’s right‑to‑left evaluation order and the way Rank reshapes the argument arrays raise uncertainty about whether the operator might swap the arguments or otherwise alter their binding.
Does the Rank operator preserve the original argument order for dyadic functions? If it does not, under what conditions does the order change? How can one verify the actual argument ordering in a Dyalog APL session?