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Dynamic predicates

Author(s): The CLIP Group.

Version: 1.10#6 (2004/8/7, 21:46:39 CEST)

Version of last change: 1.9#197 (2003/12/19, 17:4:32 CET)

This module implements the assert/retract family of predicates to manipulate dynamic predicates.

The predicates defined in this module allow modification of the program as it is actually running. Clauses can be added to the program (asserted) or removed from the program (retracted). For these predicates, the argument which corresponds to the clause head must be instantiated to an atom or a compound term. The argument corresponding to the clause must be instantiated either to a term Head :- Body or, if the body part is empty, to Head. An empty body part is represented as true. Note that using this library is very detrimental to global analysis, and that for most uses the predicates listed in section Fast/concurrent update of facts suffice.

Usage and interface (dynamic)

Documentation on exports (dynamic)

PREDICATE: asserta/1:

Meta-predicate with arguments: asserta(clause).

Usage: asserta(+Clause) * ISO *

PREDICATE: asserta/2:

Meta-predicate with arguments: asserta(clause,?).

Usage: asserta(+Clause, -Ref)

PREDICATE: assertz/1:

Meta-predicate with arguments: assertz(clause).

Usage: assertz(+Clause) * ISO *

PREDICATE: assertz/2:

Meta-predicate with arguments: assertz(clause,?).

Usage: assertz(+Clause, -Ref)

PREDICATE: assert/1:

Meta-predicate with arguments: assert(clause).

Usage: assert(+Clause)

PREDICATE: assert/2:

Meta-predicate with arguments: assert(clause,?).

Usage: assert(+Clause, -Ref)

PREDICATE: retract/1:

Meta-predicate with arguments: retract(clause).

Usage: retract(+Clause) * ISO *

PREDICATE: retractall/1:

Meta-predicate with arguments: retractall(fact).

Usage: retractall(+Head)

PREDICATE: abolish/1:

Meta-predicate with arguments: abolish(spec).

Usage: abolish(+Spec) * ISO *

PREDICATE: clause/2:

Meta-predicate with arguments: clause(fact,?).

Usage: clause(+Head, ?Body) * ISO *

PREDICATE: clause/3:

clause(Head, Body, Ref)

Like clause(Head,Body), plus the clause is uniquely identified by Ref.

Meta-predicate with arguments: clause(fact,?,?).

Usage 1: clause(+Head, ?Body, ?Ref)

Usage 2: clause(?Head, ?Body, +Ref)

PREDICATE: current_predicate/1:

Usage: current_predicate(?Spec) * ISO *

PREDICATE: current_predicate/2:

Usage: current_predicate(?Spec, ?Module)

PREDICATE: dynamic/1:

dynamic Spec

Spec is of the form F/A. The predicate named F with arity A is made dynamic in the current module at runtime (useful for predicate names generated on-the-fly). If the predicate functor name F is uninstatiated, a new, unique, predicate name is generated at runtime.

PREDICATE: data/1:

data Spec

Spec is of the form F/A. The predicate named F with arity A is made data in the current module at runtime (useful for predicate names generated on-the-fly). If the predicate functor name F is uninstatiated, a new, unique, predicate name is generated at runtime.

PREDICATE: wellformed_body/3:

wellformed_body(BodyIn, Env, BodyOut)

BodyIn is a well-formed clause body. BodyOut is its counterpart with no single-variable meta-goals (i.e., with call(X) for X). Env denotes if global cuts are admissible in BodyIn (+ if they are, - if they are not).

Documentation on multifiles (dynamic)

PREDICATE: do_on_abolish/1:

do_on_abolish(Head)

A hook predicate which will be called when the definition of the predicate of Head is abolished.

The predicate is multifile.


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