[embedding-shape]

Imperative: Tell the computer how to do something, by instructing it what to do.

Declarative: Tell the computer what you want the result to be like, and the computer figures out how to do it.

for_each in Terraform is very much declarative, just like modules. Compare how you'd do the same thing with JS or any other (imperative) language you know, and I think it must be clear what the difference between the two is.

[zaphar]

Those boundaries are pretty fuzzy. The complexity of the logic with conditionals and loops in a module means that you have pretty much stopped describing what it should like and instead described how to make it look the way you want it.

I have read terraform modules where I had to execute the logic to know what got produced which moves it from your imperative description to the declarative description as far as I'm concerned.