Helper like ability to inject some logic based on resource attributes?

Hi there!
Looking for some input on how to implement ruby based method to do some logic based on resource attributes.

output "test" {
  value       = "<%= some_helper( %>"

Believe it’s not possible as the helper methods are called at compile-time vs apply-time. See: How Terraspace Works

At ERB compile-time, the is not yet resolved and known by terraform. The logic would need to be done with vanilla terraform constructs instead of terraspace helper methods.