@export directive

I was reading through the documentation and I found a few mentions of the @export directive.

I can see how you can easily create a custom directive. My plan of action would be to add the variable when the directive is resolved, but I don't know where to hook it up so you don't hit the Variable $xxx is used by anonymous query but not declared error. (I also don't know if the query is done top to bottom, so if I would add the @export directive on top and then use it later, if that would work.

Having very little experience with the source code of this gem, I was wondering if you deem it feasible to implement an @export directive with the current hooks. Any pointers in a specific direction would also be super helpful 😄.

(running the resolve and changing the variable is also not very clean at the moment in my proof of concept)
I'm doing

context.query.variables.instance_eval("@storage")[arguments[:as]]

Which obviously goes deep in the internals of the implementation. But I don't know if there's a cleaner way for this?

Start by tracing custom directive resolution, variable validation around the “Variable $xxx is used by anonymous query but not declared” error, and the behavior of context.query.variables. Determine whether directive order supports exporting a value for later use and identify a public hook that avoids direct access to @storage; done means @export works without that internal workaround.