You don't really get credit for being "both". There are maintainability and comprehensibility benefits to keeping anything imperative out of a language (you don't have to reason causally from one statement to the next), which is out the window when you introduce imperative elements. Also: in a Dockerfile, those imperative elements are the heart of the system.

`ENV` is a bad example because it's effect differs greatly from where it's placed in the Dockerfile. Eg: before a RUN statement consuming it's value or after.

`FROM` also has more use cases when using multi stage builds.

oh, you're right. I forgot that a key characteristic of anything being "declarative" is that order of statements should not matter.

Acutally, come to think of it, since `RUN` may depend on any other Dockerfile statement (even `EXPOSE` might make a difference in code), does this mean that even a single imperative statement that is introduced in some language, makes the language imperative?