Retracted: Use the path github.com/open-policy-agent/opa (lower-case), not github.com/open-policy-agent/OPA.
Before 0.15.0 OPA was not using go modules and the correct import path was not enforced.
Base returns the list of base data documents that the given AST element depends on.
The returned refs are always constant and are truncated at any point where they become
dynamic. That is, a ref like data.a.b[x] will be truncated to data.a.b.
Minimal returns the list of data ast.Refs that the given AST element depends on.
If an AST element depends on a ast.Ref that is a prefix of another dependency, the
ast.Ref that is the prefix of the other will be the only one in the returned list.
As an example, if an element depends on data.x and data.x.y, only data.x will
be in the returned list.
Virtual returns the list of virtual data documents that the given AST element depends
on.
The returned refs are always constant and are truncated at any point where they become
dynamic. That is, a ref like data.a.b[x] will be truncated to data.a.b.