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.
- temporary
- Module is temporary.
- 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. See also predicate_property/2.
Succeeds with an empty list if the module exports no predicates.
- exported_operators(-ListOfOperators)
- True if Module exports the given operators. Each exported
operator is represented as a term
op(Pri,Assoc,Name).
Succeeds with an empty list if the module exports no operators.
- size(-Bytes)
- Total size in bytes used to represent the module. This includes the
module itself, its (hash) tables and the summed size of all predicates
defined in this module. See also the
size(Bytes) property
in predicate_property/2.
- program_size(-Bytes)
- Memory (in bytes) used for storing the predicates of this module. This
figure includes the predicate header and clauses.
- program_space(-Bytes)
- If present, this number limits the
program_size. See
set_module/1.
- last_modified_generation(-Generation)
- Integer expression the last database generation where a clause was added
or removed from a predicate that is implemented in this module. See also predicate_property/2.
- 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 6.10.
- class(+Class)
- Set the class of the module. See module_property/2.
- program_space(+Bytes)
- Maximum amount of memory used to store the predicates defined inside the
module. Raises a permission error if the current usage is above the
requested limit. Setting the limit to 0 (zero) removes the limit. An
attempt to assert clauses that causes the limit to be exceeded causes a
resource_error(program_space) exception. See assertz/1
and
module_property/2.
