> If you remove the ability to solve it in your build system the complexity will move to other systems.
Adding to this: I think one of the main limitations of purely declarative (e.g. YAML-based) configurations is that a declarative DSL (as opposed to an imperative DSL) means you (only) get to use config options the inventors of the config language have thought of and implemented (i.e. "defined"). You cannot put into words things that require vocabulary that doesn't exist in your language.
Meanwhile, an imperative language gives you the ability to define on your own what you would like the machine to do.
As an example, consider Gitlab CI configs (YAML-based) or Ansible playbooks. In both cases, once you hit the boundaries of the DSL spec (which, in my experience, typically happens on day one) you can't do anything other than 1) give up or 2) leave the realms of the DSL and as you say,
Well thought and I can imagine this can be further differentiated. E.g. what is considered boundaries or limits in a declarative way also work as guardrails. So while it could be possible to hit actual limits on day one, there is often more than only two options to go on. Declarative for me often appears easier to find the correct one or to correctly know that that system is not designed to do that.
The other differentiation I think is worth on the following part, also which I'd liked a lot btw:
> move [the complexity] to other systems
which stemmed from:
> If you remove the ability to solve it in your build system the complexity will move to other systems.
I think it is even _more_ beneficial to consider that this does not start at the build system:
If you don't have and don't add the ability at development (make it a property of the project), the complexity will continue to _increase_ each time you move it into other systems after it (build, version control, CI, ... etc.).
Glad someone else brought up this topic and phrased it way better than I ever could have!
This other comment further down puts it very well, too: https://hackertimes.com/item?id=34892724
> If you remove the ability to solve it in your build system the complexity will move to other systems.
Adding to this: I think one of the main limitations of purely declarative (e.g. YAML-based) configurations is that a declarative DSL (as opposed to an imperative DSL) means you (only) get to use config options the inventors of the config language have thought of and implemented (i.e. "defined"). You cannot put into words things that require vocabulary that doesn't exist in your language.
Meanwhile, an imperative language gives you the ability to define on your own what you would like the machine to do.
As an example, consider Gitlab CI configs (YAML-based) or Ansible playbooks. In both cases, once you hit the boundaries of the DSL spec (which, in my experience, typically happens on day one) you can't do anything other than 1) give up or 2) leave the realms of the DSL and as you say,
> move [the complexity] to other systems