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Predicate abolish/1
Availability:built-in
[ISO]abolish(:PredicateIndicator)
Removes all clauses of a predicate with functor Functor and arity Arity from the database. All predicate attributes (dynamic, multifile, index, etc.) are reset to their defaults. Abolishing an imported predicate only removes the import link; the predicate will keep its old definition in its definition module.

According to the ISO standard, abolish/1 can only be applied to dynamic procedures. This is odd, as for dealing with dynamic procedures there is already retract/1 and retractall/1. The abolish/1 predicate was introduced in DEC-10 Prolog precisely for dealing with static procedures. In SWI-Prolog, abolish/1 works on static procedures, unless the Prolog flag iso is set to true.

It is advised to use retractall/1 for erasing all clauses of a dynamic predicate.

Examples

retractall/1 or abolish/1?

retractall/1 or abolish/1?

The retractall/1 predicate removes all clauses whose head matches the argument from a dynamic predicate. The abolish/1 predicate takes a predicate indicator to remove all clauses and all properties.

:- dynamic p/1.

?- assertz(p(a)).
?- assertz(p(b)).
?- retractall(p(b)).
?- p(a).
true.
?- p(b).
false.
?- retractall(p(_)).
?- p(X).
false.
?- assertz(p(a)).
?- assertz(p(b)).
?- abolish(p/1).
?- p(X).
ERROR: Unknown procedure: p/1 (DWIM could not correct goal)
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LogicalCaptain said (2020-10-01T19:54:22):0 upvotes 0 0 downvotes
Picture of user LogicalCaptain.

We read:

"all clauses of a predicate with functor Functor and arity Arity"

However,

The "functor" is the tuple (predicate name, arity). That tuple can be given as a predicate indicator which is a program element that looks like this: Name/Arity.

So the text should say:

"all clauses of the predicate designated by given predicate indicator Name/Arity"

Also

"This is odd" is a nice way of saying "the standard is wrong". That the standard can be wrong is hardly surprising...