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I'd say both.

Some is declarative, e.g. `FROM`, `ENV`, `EXPOSE`. While on the other hand `RUN`, `CMD`, etc. is fully imperative.

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?

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