Oh, I get it. No, this is not something you can do with macrology because there is no room for a macro in your desired syntax (where you just want the list itself and the index values). As you say, if you'll make room for another token it can just be a function (which would be fun to generalize to N dimensions). As for making ((list (list 42)) 0 0) return 42, I think you need to is suggest it as a (very reasonable) enhancement to Arc.
