/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 1985-2011, University of Amsterdam VU University Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(swi_system_utilities, [ lock_predicate/1, unlock_predicate/1, system_mode/1, system_module/0 ]). :- autoload(library(error),[must_be/2]). /** System utilities This module provides some tools to deal with system predicates. System predicates cannot be traced or redefined. @deprecated Use :- set_prolog_flag(generate_debug_info, false) to hide predicate internals from the tracer. @tbd Move this functionality to prolog flags. */ %! system_mode(+Boolean) is det. % % Switch the system into system or user mode. When in system mode, % system predicates loose most of their special properties, so it % becomes possible to trace and even redefine them. % % @deprecated New code should use the prolog flag =access_level=. system_mode(Val) :- must_be(boolean, Val), ( Val == true -> set_prolog_flag(access_level, system) ; set_prolog_flag(access_level, user) ). %! system_module % % Any predicate defined after this declaraction uptil the end of % the file will become a system predicate. Normally invoked by a % directive immediately following the module declaration. system_module :- set_prolog_flag(generate_debug_info, false). :- meta_predicate lock_predicate(:), unlock_predicate(:). %! lock_predicate(+PredInd) % % Transform a predicate into a system predicate. lock_predicate(PredInd) :- '$set_predicate_attribute'(PredInd, system, true). %! unlock_predicate(+PredInd) % % Transform a system predicate into a normal system predicate. unlock_predicate(PredInd) :- '$set_predicate_attribute'(PredInd, system, false).