The principles behind the module system of SWI-Prolog differ in a number of aspects from the Quintus Prolog module system.
The meta_predicate/1 declaration causes the compiler to tag arguments
that pass module sensitive information with the module using the
:/2 operator. This approach has some disadvantages:
Unfortunately the transparent predicate approach also has some
disadvantages. If a predicate A passes module sensitive information
to a predicate B, passing the same information to a module
sensitive system predicate both A and B should be declared
transparent. Using the Quintus approach only A needs to be
treated special (i.e. declared with meta_predicate/1)
.
A second problem arises if the body of a transparent predicate uses
module sensitive predicates for which it wants to refer to its own
module. Suppose we want to define findall/3 using assert/1 and
retract/1
.
The example in figure 
gives the solution.
The Quintus meta_predicate/1 directive can in many cases be replaced by
the transparent declaration. Figure gives a definition
of meta_predicate/1 as available from the `quintus' library package.
Figure: Definition of meta_predicate/1
The discussion above about the problems with the transparent mechanism
