1:- module(random_temporary, [random_temporary_module/1]).

 random_temporary_module(-M:atom) is nondet

Finds a module that does not exist. Makes it exist. The new module has a module class of temporary. Operates non-deterministically by continuously generating a newly unique temporary module. Surround with once/1 when generating just a single module.

Utilises the uuid/1 predicate which never fails; the implementation relies on that prerequisite. Nor does uuid/1 automatically generate a randomly unique identifier. The implementation repeats on failure to find a module that does not already exist. If the generation of a new unique module name always fails, the predicate will continue an infinite failure-driven loop running until interrupted within the calling thread.

The predicate allows for concurrency by operating a mutex across the clauses testing for an existing module and its creation. Succeeds only for mode (-).

   22random_temporary_module(M) :-
   23    var(M),
   24    repeat,
   25    uuid(M),
   26    with_mutex(random_temporary_module, unique_module(M)).
   27
   28unique_module(M) :-
   29    \+ current_module(M),
   30    set_module(M:class(temporary))