Filed predicates (runtime)

Usage:asserta_fact(Fact)

Version of data_facts:asserta_fact/1 for filed predicates. The current instance of Fact is interpreted as a fact and is added at the beginning of the definition of the corresponding predicate. Therefore, before all the facts filed in the DB file for the predicate. The predicate concerned must be declared as facts; if it is not, then data_facts:asserta_fact/1 is used.

• The following properties should hold at call time:
  (basic_props:callable/1)Fact is a term which represents a goal, i.e., an atom or a structure.

Usage:assertz_fact(Fact)

Version of data_facts:assertz_fact/1 for filed predicates. The current instance of Fact is interpreted as a fact and is added at the end of the definition of the corresponding predicate. Therefore, after all the facts filed in the DB file for the predicate. The predicate concerned must be declared as facts; if it is not, then data_facts:assertz_fact/1 is used.

• The following properties should hold at call time:
  (basic_props:callable/1)Fact is a term which represents a goal, i.e., an atom or a structure.

Usage:call(Fact)

Same as current_fact/1 if the predicate concerned is declared as facts. If it is not, an exception is raised.

• The following properties should hold at call time:
  (basic_props:callable/1)Fact is a term which represents a goal, i.e., an atom or a structure.

Usage:current_fact(Fact)

Version of data_facts:current_fact/1 for filed predicates. The current instance of Fact is interpreted as a fact and is unified with an actual fact in the current definition of the corresponding predicate. Therefore, with a fact previously asserted or filed in the DB file for the predicate, if it has not been retracted. The predicate concerned must be declared as facts; if it is not, then data_facts:current_fact/1 is used.

• The following properties should hold at call time:
  (basic_props:callable/1)Fact is a term which represents a goal, i.e., an atom or a structure.

Usage:retract_fact(Fact)

Version of data_facts:retract_fact/1 for filed predicates. The current instance of Fact is interpreted as a fact and is unified with an actual fact in the current definition of the corresponding predicate; such a fact is deleted from the predicate definition. This is true even for the facts filed in the DB file for the predicate; but these are NOT deleted from the file (unless the predicate is persistent). The predicate concerned must be declared as facts; if it is not, then data_facts:retract_fact/1 is used.

• The following properties should hold at call time:
  (basic_props:callable/1)Fact is a term which represents a goal, i.e., an atom or a structure.

Predicate Spec is filed within database Key. Programmers should not define this predicate directly in the program. The predicate is multifile.

Usage::- facts(PredDesc,Keyword).

Declares the predicate PredDesc as filed. Keyword is the identifier of a location where the file DB for the predicate is kept. The location Keyword is described in the file_alias predicate, which must contain a fact in which the first argument unifies with Keyword.

• The following properties should hold upon exit:
  (basic_props:predname/1)PredDesc is a Name/Arity structure denoting a predicate name:

  predname(P/A) :-
          atm(P),
          nnegint(A).
  

  
  (persdb_cache:keyword/1)Keyword is an atom corresponding to a directory identifier.