SWI-Prolog 7.1.16 Reference Manual: Section 5.14

## 5.14 Module properties

The following predicates can be used to query the module system for reflexive programming:

[nondet]current_module(?Module)
  True if Module is a currently defined module. This predicate enumerates all modules, whether loaded from a file or created dynamically. Note that modules cannot be destroyed in the current version of SWI-Prolog.
module_property(?Module, ?Property)
  True if Property is a property of Module. Defined properties are:
  class(-Class)
    True when Class is the class of the module. Defined classes are
    user
      Default for user-defined modules.
    system
      Module `system` and modules from `<home>/boot`.
    library
      Other modules from the system directories.
    test
      Modules that create tests.
    development
      Modules that only support the development environment.
  file(?File)
    True if Module was loaded from File.
  line_count(-Line)
    True if Module was loaded from the N-th line of file.
  exports(-ListOfPredicateIndicators)
    True if Module exports the given predicates. Predicate indicators are in canonical form (i.e., always using name/arity and never the DCG form name//arity). Future versions may also use the DCG form and include public operators. See also predicate_property/2.
  exported_operators(-ListOfOperators)
    True if Module exports the given operators. Each exported operator is represented as a term `op(Pri,Assoc,Name)`.
set_module(:Property)
  Modify properties of the module. Currently, the following properties may be modified:
  base(+Base)
    Set the default import module of the current module to Module. Typically, Module is one of `user` or `system`. See section 5.9.
  class(+Class)
    Set the class of the module. See module_property/2.