Yeah, that's why I would consider a Makefile declarative even though it can contain bits saying how to do something. I can't consider a Dockerfile declarative simply because it is necessarily executed top to bottom.
An array can be declarative even if it has order. Think of the ordered list of statements in a Dockerfile as syntax sugar for a linked list of (previousLayerPointer, nextLayerDeclaration) tuples. I expanded on this in another comment.
