================================================================= Logtalk - Object oriented extension to Prolog Release 2.27.0 Copyright (c) 1998-2006 Paulo Moura. All Rights Reserved. ================================================================= This folder contains several examples of Logtalk programs. A brief description of each example is included below. Each example folder contains a NOTES file and a loader helper file which may be used to load all the example entities. In addition, most examples contain a SCRIPT file with instructions on how to load the example and sample queries for your to try. Most of these examples need objects, protocols, and categories which are defined in the Logtalk standard library or in other examples. See the NOTES files inside the library folder, plus the NOTES and SCRIPT files inside each example folder. Some examples may redefine objects already loaded from other examples. You may want to restart Logtalk after trying each example. Some of the examples code have been adopted from public available Prolog code or from known Prolog text books and are copyrighted by the respective authors. These are programming examples, meaning that you should study the source files to fully understand them. All examples are formatted using four spaces tabs. By default, compiling an example generates a .xml documenting file for each compiled entity (object, category, or protocol). See the "xml" folder for instructions on how to browse the .xml files for on-line reading or how to convert the files to a print-ready format such as PDF. Here is a short description of each included example: aliases example of using the alias/3 predicate directive to provide alternative names to inherited predicates in order to improve readability or to solve multi-inheritance conflicts assignvars example of using assignable variables in the context of parametric objects benchmarks simple benchmarks for helping measuring performance of Logtalk message sending between Prolog compilers and for comparing performance of message sending calls with predicate calls in plain Prolog birds bird identification expert system (example adopted from the Adventure in Prolog Amzi! book) bricks example of representation and handling of relations using events classvars example of implementation of class variables (as found in Smalltalk; i.e. shared instance variables) dcgs examples of using DCG rules inside objects and categories diamonds examples of problems and solutions for the "diamond problem" (multi-inheritance conflicts and ambiguities) dynpred example of using some of the built-in database handling methods encodings very simple example of using the new, experimental encoding/1 directive (requires Logtalk to be run with the SWI-Prolog compiler) engines example of category composition (importation of categories by other categories) using car engines errors example showing the Logtalk compiler warning and error reporting for common programming errors hello_world the unavoidable "hello world" programming example hooks simple example of using compiler hook predicates inheritance examples of public, protected, and private inheritance using both prototypes and classes/instances instmethods example of instance defined methods lo examples adopted from the Francis G. McCabe L&O system logic example of a translator of first-order predicate logic propositions to conjunctive normal form and to clausal form lpa examples adopted from the LPA Prolog++ system metapredicates example of using metapredicates in Logtalk objects metainterpreters some examples of simple metainterpreters mi multi-inheritance examples miscellaneous unsorted examples modules simple example of compiling Prolog module files as objects msglog example of using events and monitors for recording, replaying, and printing user messages operators example of using operators local to objects and categories parametric simple example of parametric objects poem examples adopted from the Ben Staveley-Taylor POEM system points example adopted from SICStus Objects documentation polygons example of representation and handling of relations using events profiling examples of using of events and monitors to implement profilers puzzles several examples of logical puzzles reflection example of a simple class-based reflective system relations objects implementing predicates for dealing with relations and constrained relations between objects roots objects, protocols, and categories needed by most of the other examples; searching state-space searching framework (example adopted from Ivan Bratko's "Prolog Programming for Artificial Intelligence" book) shapes geometric shapes implemented as both a prototype hierarchy and a class hierarchy sicstus examples adopted from SICStus Objects documentation symdiff example of using parametric objects to implement symbolic expression differentiation and simplification viewpoints example on how to implement property and value sharing with prototypes