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This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2023 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

dif

The dif object provides a portable abstraction over how the dif/2 predicate is made available by the supported backend Prolog systems that implement it (B-Prolog, ECLiPSe, XVM, SICStus Prolog, SWI-Prolog, Trealla Prolog, XSB, and YAP).

Calls to the library predicates are inlined when compiled with the optimize flag turned on. In this case, there is no overhead compared with calling the abstracted predicate directly.

See also the coroutining library.

API documentation

Open the [../../docs/library_index.html#dif](../../docs/library_index.html#dif) link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

| ?- logtalk_load(dif(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(dif(tester)).

Usage

Load this library from your application loader file. To call the dif/1-2 predicates using implicit message-sending, add the following directive to any object or category calling the predicates:

:- uses(dif, [
        dif/2, dif/1
]).