Interesting. I've never heard of D-list nomenclature before.

With the A-list method you typically need to write a "zipper" function, that recursively conses the heads of two lists to generate the A-list. Makes "apply" an expensive operation with needless allocations.

What's great about D-lists is that the "make-env" method is just a single cons operation. Clearly superior. I'm surprised its not more well known.