Query

We start the evaluation process by putting a query to a concrete module of an application. This process will end up by answering with the value obtained for that query. An example of query to the module sponges can be Query(sponges, taxon).

Assume that the query is q. There are two possible cases to consider:

1. is a path: If the fact is a path to a submodule sm of the current module, and if that submodule is visible (see Section 7), it makes a query to that submodule , otherwise it raises an error.
2. q is a fact: If q belongs to the export interface of m it starts Eval(q) in that module returning the value of fact q; otherwise it raises an error.