Dittos on the $$r{k} looking wrong; reads more clearly to me written as $r->{k} (or if you insist on not using -> then make the dereferencing visually explicit with ${ $r }{ k }).

Edit: Appeal to authority, but quoth PBP chapter 11 "Wherever possible, dereference with arrows."; I just skimmed the modern PBP videos and didn't find anything explicitly contradicting this so . . .