Not key value dictionaries, just pointers are needed. A closure with no behaviour is just a pointer to the enclosed variable. A closure with 2 pointers is a p

Not key value dictionaries, just pointers are needed. A closure with no behaviour is just a pointer to the enclosed variable. A closure with 2 pointers is a pair, which you can get the car and cdr. The runtime needs to make the pointee available outside its definition, so escape analysis, garbage collection, etc. But no dictionary is needed.