@ngn I do have the basics of prototypes already done too, it's just that everywhere I'm making arrays with new Arr(items, shape) and I need to add a prototype set to that too..
@dzaima that's duplication of information; for non-empty arrays the structure of ⊃A determines the prototype - just replace everything recursively with 0s and spaces
for ngn/k I'm thinking of introducing a compromise between the APL way and what's rumoured to be in k6
typed empty arrays remain as they are, with their implicit prototypes; generic empty arrays lose their prototypes (it will be something fixed, doesn't matter much what)