retract/1

Description

retract(Clause)
retract((Head:-Body))

Retracts a dynamic clause from an object.

Template and modes

retract(+clause)

Errors

Head is a variable:

instantiation_error

Head is neither a variable nor a callable term:

type_error(callable, Head)

The predicate indicator of Head is that of a private predicate:

permission_error(modify, private_predicate, Head)

The predicate indicator of Head is that of a protected predicate:

permission_error(modify, protected_predicate, Head)

The predicate indicator of Head is that of a static predicate:

permission_error(modify, static_predicate, Head)

The predicate indicator of Head is not declared:

existence_error(predicate_declaration, Head)

Examples

To retract a matching clause of any dynamic predicate in this:

retract(Clause)

To retract a matching clause of a public or protected dynamic predicate in self:

::retract(Clause)

To retract a matching clause of a public dynamic predicate in an object:

Object::retract(Clause)