================================================================= Logtalk - Object oriented extension to Prolog Release 2.17.1 Copyright (c) 1998-2004 Paulo Moura. All Rights Reserved. ================================================================= RELEASE NOTES ============= 2.17.1 - June 7, 2004 Added custom handling of specification of predicate exceptions in info/2 documenting directives when writing XML documenting files (declared as "exceptions is [Cond1-Term1, Cond2-Term2, ...]"; each pair (Condi, Termi) represents an error condition and its respective exception). Changed debugger command "e" to print exception terms instead of exiting Logtalk session. Corrected a compilation error with B-Prolog due to operator priorities. Corrected a possible problem with the redefinition of loaded entities that define (possibly at runtime) dynamic predicates. All clauses for an entity dynamic predicates are retracted before loading the new entity definition. Corrected a potential bug when pretty printing terms with variables in the debugger and in the created XML documenting files. Added four more DCGs examples ("walker movements", "iterative shell command parsing", "bill of materials", and "command language"). New "puzzles" and "metainterpreters" examples. Added a mode bundle for the SubEthaEdit 2.x (MacOS X) text editor providing syntax coloring for editing Logtalk source files. Optimized some of the regular expressions in the syntax coloring files for the Kate/Kwrite and Vim text editors. Removed predicate nth/3 from library entities listp, list, and difflist. Replaced by the predicates nth0/3 and nth1/3. Added new predicates nth1/4 and nth0/4. Updated the config file for Quintus Prolog to make use of the "files" library. Added experimental implementations for some Prolog compilers of the library portable protocol for operating system access (systemp.lgt). See the file library/experimental/NOTES for details. 2.17.0 - April 26, 2004 Added built-in debugging support implemented through the definition of a new pseudo-object named "debugger". Added "debug" compiler option. Renamed library entities "debuggerp" and "debugger" to, respectively, "event_dbgp" and "event_dbg". Improved installation instructions for multi-user environments. Added a shell script for installing Logtalk in Unix and Unix-like operating systems. Added a shell script for copying Logtalk xml, examples, and library directories to the user home directory. Added a logtalk.spec file for building Linux RPMs from sources. Added a set of shell scripts for easy integration of Logtalk with ECLiPSe, GNU Prolog, Qu-Prolog, SICStus Prolog, SWI-Prolog, and YAP. Corrected bug in the definition of the pseudo-object "user" that resulted in mixed up metapredicate and type predicate properties. Removed config files for outdated versions of Qu-Prolog, SWI-Prolog, ECLiPSe, K-Prolog, CIAO, YAP, Amzi! Prolog, LPA Win-Prolog, SICStus Prolog, and XSB. 2.16.2 - April 2, 2004 Corrected a bug in the library category monitor (file library/monitor.lgt) that prevents its compilation. Changed the possible values of the read-only flag startup_message (defined in the config files) to "flags" (print banner and flag values), "banner" (print only the banner), and "none" (do not print neither the banner nor the flag values). Default value is "flags". Updated the "errors" example to illustrate the error messages thrown when trying to redefine Logtalk built-in control constructs. Corrected a small problem with the Logtalk language specification file for Apple's Xcode IDE. Added preliminary support for syntax coloring using the Windows text editor Crimson Editor. 2.16.1 - March 23, 2004 The local built-in method parameter/2 can now be used inside categories (but please read the warnings about such practice on the user manual). Updated the Logtalk compiler to report an error when the user tries to redefine a message sending or external call control construct inside an object or category. Corrected a bug in the compilation of metacalls whose meta-arguments are variables. Removed references to file sax.jar from the scripts used to convert XML documenting files into (X)HTML. Updated scripts html.sh, htmlnt.cmd, and htmldos.bat to use XT 20020426a or later version. Improved syntax coloring accuracy of built-in predicates and methods for the SubEthaEdit text editor. Updated config file for Qu-Prolog 6.4. 2.16.0 - March 3, 2004 Logtalk is now distributed under the Artistic License 2.0. Operators declared inside an entity are now local to the entity, not affecting the global operator table (complying with the Logtalk language specification). Input and output of terms from inside objects and categories now work as expected in the presence of local operator declarations. Added a new example named "operators". Updated built-in method predicate_property/2 for returning metapredicate/1 properties for both Logtalk and Prolog metapredicates. Added support for calls to non-ISO Prolog standard built-in metapredicates inside objects and categories. Added support for the declaration of non-ISO Prolog standard metapredicates in the config files. Small change to the way the Logtalk compiler reports the compilation of entities. Small optimizations to the compilation of Logtalk source files. Corrected a bug where calls to Logtalk built-in predicates would be reported as non-portable when the value of compiler option portability is set to warning. New config file for Qu-Prolog 6.4 (see the configs/NOTES file for details). Corrected a problem with the syntax coloring of quoted atoms and strings in the SubEthaEdit text editor. Added more accurate syntax highlight for built-in methods and built-in predicates. Updated the syntax coloring configuration files for all supported text editors to recognize the file extension used by the config files. 2.15.6 - February 9, 2004 Added "xmlspec" compiler option in order to specify the extension (dtd or xsd) of the file describing the XML documenting files specification. Renamed compiler option "named_anonymous_vars" to the more appropriated name "underscore_vars". Changed possible option values to "dont_care" and "singletons" (default). Added XSLT file for converting XML documenting files to XHTML 1.0 Strict files. Set the default encoding of all XSLT files to UTF-8. Added syntax coloring support for the KDE Kate and Kwrite text editors. Improved syntax coloring configuration files for VIM, jEdit, NEdit, SubEthaEdit, and Emacs text editors. Removed outdated support for MacOS X Project Builder and added support for the new MacOS X Xcode developer tool. Corrected bug in the built-in predicate current_logtalk_flag/2 that prevented some flag values from being returned after using the built-in predicate set_logtalk_flag/2. Corrected bug in the shapes example (wrong placement of the declaration of the predicate side/1). 2.15.5 - December 30, 2003 Make operator ^^/1 right-associative for consistency with remaining operator declarations. Added file BIBLIOGRAPHY containing a list of Logtalk publications in BibTeX format. Added a font-lock file for Emacs providing syntax coloring for editing Logtalk source files. Added an implementation of the Smalltalk dependent mechanism to the standard Logtalk library. Updated the config file for ECLiPSe 5.4~5.7 with missing ISO Prolog predicate definitions needed for successful compilation of all entities in the Logtalk standard library. Updated manual pages to comply with XHTML 1.0 Strict and to provide better navigation. 2.15.4 - July 9, 2003 Corrected a spurious backtracking bug in the DCG rule translator. Added two more examples of DCGs. New config file for XSB 2.6. Updated Logtalk compiler to compile cleanly under XSB after applying the patch described in configs/NOTES. Updated SWI-Prolog config file to hide compiled entity predicates (requires SWI-Prolog 5.2.3 or later version). New optional file configs/swihook.pl contains hook code that allows Logtalk entities to be compiled and loaded using SWI-Prolog load_files/2 and consult/1 predicates. Syntax definition file for the Hydra 1.1 (MacOS X) text editor providing syntax coloring for editing Logtalk source files. Updated syntax coloring files for jEdit, NEdit, Vim, and TextPad in order to recognize character code constants (0'x) and the DCG operator -->/2. 2.15.3 - June 27, 2003 Updated experimental support for DCG rules to prevent over-simplification of unification goals in the compilation of rules to clauses. Push-back lists can now be used on rule heads. The compilation mode of an entity (static/dynamic) is now stored in the corresponding entity table (implying recompilation of all entities). Updated GNU Prolog config file to hide compiled entity predicates. Updated SWI-Prolog config file for better integration of Logtalk with this compiler. 2.15.2 - April 2, 2003 Experimental support for DCG rules inside categories and objects. Added built-in methods phrase/2 and phrase/3. Updated GNU Prolog config file to not hide compiled entity predicates in order to avoid incompatibilities with dynamic entities. 2.15.1 - March 8, 2003 New example, msglog, of using events and monitors to record, replay, and print user messages. Corrected a typo on the jEdit templates that resulted in syntax errors. Corrected wrong year format in info/1 directive in all entity templates. Added missing version info key to jEdit prototype template. Corrected documentation of built-in local methods self/1 and sender/1. Updated documentation of built-in local methods parameter/2 and this/1. 2.15.0 - February 5, 2003 Changed "authors" key in info/1 directive to "author". Corrected documentation of built-in local method this/1. New geometric shapes example implemented in two versions, one prototype-based and the other one class-based. Improved support for jEdit text editor by adding a set of programming templates for use with the editor Templates plug-in. Added basic support for syntax highlighting and programming templates for MacOS X Project builder. 2.14.7 - January 10, 2003 Corrected a bug in the built-in methods asserta/1 and assertz/1 when asserting predicate rules. The built-in predicates logtalk_compile/1-2 and logtalk_load/1-2 now accept both an entity (an atom) or a list of entities (a list of atoms). Optimized the code generated when compiling or asserting clauses for dynamic predicates. Optimized protected inheritance performance on some Prolog compilers. 2.14.6 - December 31, 2002 Corrected a bug where the opening directive of an object that, simultaneously, implements a protocol, imports a categoty, instantiates a class, and specializes a superclass, will not be recognized. 2.14.5 - December 20, 2002 Simplified dynamic table of predicate declarations by removing two redundant arguments. Corrected a bug where sending messages such as true/0 or !/0 to an unknown object succeeded instead of throwing the correct exception. Simplified the code used to generate links in the lgtpdfa4.xsl and lgtpdfus.xsl XSLT files. 2.14.4 - November 5, 2002 Removed definition of depracated built-in predicate logtalk_version/3. Show flag names when printing at startup the default flag values. Small change to messages printed on console with smart compilation of source files turned on. Updated YAP 4.3.x config file to use the YAP "system" library to access the operating system for time, date, and file properties (enabling smart source code compilation). Updated the lgtpdfa4.xsl and lgtpdfus.xsl XSLT files to workaround a bug in the PassiveTeX 1.21 XSL:FO processor. 2.14.3 - Sptember 16, 2002 New compiler option, doctype, to set the doctype reference (if any) in the XML documenting files. Default value is "local" for backward compatibility. Updated the user manual section on compiler options. The Logtalk built-in predicate logtalk_version/3 should be considered deprecated (use current_logtalk_flag/3 instead). All references to this predicate have been removed from the manuals. Updated the jEdit syntax coloring config file for the new jEdit 4.1 version. Updated the lgtpdfa4.xsl and lgtpdfus.xsl XSLT files for compatibility with the XSL:FO processors Apache FOP 0.20.4, PassiveTeX, and RenderX and with the XSL W3C Recommendation of October 15, 2001. Updated the pdf.bat and pdf.sh scripts to reference the latest version of the Apache FOP processor (0.20.4). Changed the shell scripts html.sh and pdf.sh for compatibility with the sh, bash, and zsh shells. 2.14.2 - August 26, 2002 Calls to built-in method parameter/2 are now compiled inline, improving call performance. Updated Logtalk compiler to clean temporary compilation predicates after compiling an entity instead of only before compilation. Updated YAP 4.3.x config file for better Logtalk integration by hiding all internal compiler, runtime, and compiled entities static predicates. Updated GNU Prolog config file for better Logtalk integration by hiding all internal compiler, runtime, and compiled entities predicates. Updated the XSLT conversion scripts lgtxml.xsl and lgthtml.xsl to correct some HTML conformance errors in the generated pages. Corrected some XHTML conformance errors in the manual pages. 2.14.1 - July 31, 2002 New Windows NT script and updated Unix shell script for batch converting XML documenting files to HTML. Both scripts also generate an index.html file containing links to all converted XML documenting files. Corrected wrong XHTML DOCTYPE declaration in manual pages. 2.14.0 - July 26, 2002 Renamed all compiler and runtime internal predicates and all auxiliary predicates in the config files to start with a "$" character. New compiler option, code_prefix, to set a prefix for all Prolog code functors generated by Logtalk when compiling entities. Default is ''. New compiler option, named_anonymous_vars, that instructs the compiler to interpret variables that start with an underscore as anonymous variables (and to not report them as singleton variables). Default value is "off". Directive info/2 was wrongly declared as a entity directive instead of a predicate directive. Converted all manual pages to XHTML 1.0 format. Corrected a wrong link in the reference manual. Replaced GIF images by PNG versions. Updated BProlog 6.x config file to workaround the new 6.2 built-in predicate ::/2 that conflicts with the same named Logtalk message sending operator. Removed call to the obsolete built-in predicate nodbgcomp/0 from all ECLiPSe config files. 2.13.0 - June 15, 2002 Logtalk now outputs Prolog code using write_canonical/2 instead of write_term/3. Goals are better portability of the generated Prolog files and avoid issues with clauses with long bodies for Prolog compilers that use a term print depth limit to prevent problems with cyclic terms. Added report of default flag values at Logtalk startup. Logtalk now prints a warning when redefining parametric objects. Removed need of an abort/0 predicate from the Logtalk debugger example. Removed any definition of this predicate from the config files. Added missing definitions for some ISO built-in predicates to the Amzi! Prolog 6.2.2 config file. 2.12.0 - May 25, 2002 New read-only Logtalk flag "version". Corrected exception term generated when trying to modify a read-only flag using the set_logtalk_flag/2 built-in predicate. Updated config file for OpenProlog 1.1b5. New config file for ECLiPSe 5.4. Renamed config files for CIAO 1.7 (beta of 1.8) to "ciao_aux18.config" and "ciao18.config". Updated config file for Amzi! Prolog 6.2.2. New example of using some of the built-in database handling methods (dynpred). Syntax configuration files for jEdit 4.0, VIM 6.1, NEdit 5.2, and TextPad 4.5 text editors providing syntax highlighting for editing Logtalk source files. 2.11.0 - April 22, 2002 Added a "smart compilation" feature to the Logtalk compiler, controlled by a "smart_compilation" flag. Only available in Prolog compilers that provide access to file modification dates. Added a "startup_message" flag to control printing of the Logtalk banner at startup. Reworked Logtalk pre-processor compilation and loading reports. Compiler option "report" now togles between normal reporting (as specified by the other flags) and silent compilation/loading of source files. 2.10.0 - April 5, 2002 Scope of object asserted predicates for which there is no declaration is now a function of the context instead of always being declared public. Asserting in this, the predicate is declared private, asserting in self, the predicate is declared protected, otherwise the predicate is declared public. Throw an error if a category contains clauses for dynamic predicates. Updated documentation on categories and built-in methods for database handling. Retracting all clauses for a dynamic predicate from an object now allows an inherited definition to be called when sending the corresponding message. In previous versions the message just failed. Added missing entries for the built-in predicates current_logtalk_flag/2 and set_logtalk_flag/2 to the Logtalk compiler built-in predicates table. Updated config file for Amzi! Prolog 6.1.74. Updated notes on patching XSB to work with Logtalk. 2.9.3 - February 9, 2002 New current_logtalk_flag/2 and set_logtalk_flag/2 built-in predicates. Updated documentation on new built-in predicates. Renamed SWI-Prolog config file swi330.config to swi.config. Renamed config file predicate lgt_default_compiler_option/2 to lgt_flag/2. New XSL stylesheets and shell scripts to convert Logtalk XML entity documenting files to PDF format using XSL Formating Objects. 2.9.2 - January 4, 2002 The Logtalk compiler can now print a warning when compiling source files that use non-ISO defined built-in predicates using a new portability/1 compiler option. Updated the relevant sections of the user manual and the errors example. Corrected a compiler bug where the entity relation tables only recorded the last entry per entity relation type. Updated config file for CIAO 1.7#162. 2.9.1 - December 5, 2001 Logtalk compiler now prints a warning when redefining or replacing an existing entity. Corrected a compiler bug in the error checking code for the info/1 and info/2 directives. Changed the order of object loading in the "mi" example to avoid suporious warning messages. Added a new problem ("bridge") to the "searching" example. Improved "performance" monitor to give correct reports on alternative solutions. Corrected a bug in the "water jug" state space example. 2.9.0 - October 22, 2001 Added config files for CIAO Prolog 1.7p115 and B-Prolog 6.0. Compiling and loading an entity that contains references to unknown entities (by default) prints a warning. Updated user and reference manuals. Rewrited all the compiler warning/error code and output messages. Changed compiled code functors postfixes from "_sdcl" and "_sdef" to "_idcl" and "_idef" (implies recompilation of all objects, protocols, and categories). Changed all occurrences and references to the term "entity_scope" to "scope". Removed some redundant productions from the Logtalk grammar. Updated documentation on the xml directory. Renamed some of the .xsl files. Added sample scripts to batch convert .xml files to .html files. Added a new loader utility file, all.loader, to load all library files loaded by the other loader files. Started work on documenting the Logtalk pre-processor/compiler source file. New "errors" example. Updated the "inheritance" example. 2.8.4 - March 9, 2001 Updated config files for BinProlog 8.0, K-Prolog 5.01, XSB 2.3, and Amzi! Prolog 4.103~5.0. New config file for Amzi! Prolog 6.1 beta. Corrected an incomplete entity definition in the Logtalk XML DTD. Rewrite the Logtalk XSLT files for improved compatibility with XSLT processors regarding handling of whitespace. A first cut of a XML Schema for the Logtalk XML documentation files (file xml/logtalk.xsd). Small improvements to the documentation. 2.8.3 - November 21, 2000 Corrected a bug where sending a message for a built-in method to an unknown object fails instead of generating the expected exception. Put some ocorrences of atoms public, mode, and type between ()'s to avoid compilation errors in BinProlog 8.0 and other Prolog compilers that declare these atoms as operators. Corrected the definition of the state space of the "Missionaires and Cannibals" problem in the "searching" example that resulted in some wrong solutions. 2.8.2 - November 5, 2000 New .xsl file to convert .xml files to TeXML files. Fixed a problem with explicit compilation options being correctly parsed but not processed. Corrected a bug regarding default init options definition for the points, polygons, and bricks examples. Updated category initialization in roots example. 2.8.1 - October 28, 2000 New config file for K-Prolog 5.0. Improved compiler error detection and reporting of invalid directives and clauses. Corrected a problem with some Prolog compilers where compiling a file containing syntax errors may not close the file after the errors are reported. Many small improvements to all documentation. Small improvements to the .xsl files and to the output of .xml files. 2.8.0 - October 1, 2000 I have found just a few days ago that I have uploaded to the Logtalk web server a development version of Logtalk 2.7.0 instead of the final one! To avoid confusions I decided to release a new version. Changed implementation of the logtalk_compile/1-2 and logtalk_load/1-2 predicates to only accept a list of entities instead of either an entity or a list of entities, simplifying and improving the performance of these predicates. Improved error reporting for the logtalk_compile/1 and logtalk_load/1 predicates. Updated relevant sessions in the user and reference manuals. Simplified the implementation of the following predicates, by sharing the error checking code with the corresponding extended versions: implements_protocol/2, imports_category/2, instantiates_class/2, specializes_class/2, extends_protocol/2, and extends_object/2. Completed some missing library file dependencies documentation in some examples. New version of the QUICK_START help file. Updated tutorial. 2.7.0 - August 24, 2000 First release of the Logtalk standard library of objects, protocols and categories. Rewritten all examples to use the new Logtalk standard library. New logtalk_load/2 and logtalk_compile/2 Logtalk built-in predicates, accepting a list of compiler options. See the User and Reference Manuals for details. New XSLT file for viewing .xml files in Microsoft Internet Explorer 5.5 for Windows after installing the latest Microsoft XML Parser Preview Release. Small improvements in all XSLT files. Starting with this version all config files need to provide a definition for the compare/3 predicate if it is not built-in in the corresponding Prolog compiler. Also, default Logtalk compiler options are now also set in the config files using the lgt_default_compiler_option/2 predicate. Updated config file for CIAO 1.6p1. See the configs/NOTES file for details. 2.6.2 - July 4, 2000 Improved performance and error checking for the built-in predicates create_object/4, create_protocol/3 and create_category/4. Updated config file for BinProlog 7.83. Many small updates to all documentation. New PDF versions of the documentation formated for printing (with page numbers, table of contents and index)are now available in both A4 and US letter formats. 2.6.1 - May 5, 2000 Modified the structure of the automatically generated XML documenting files to improve XSL translation performance. Added a new, more standard compliant, XSL file to generate HTML files and renamed the old one to ie5.xsl. See the xml/NOTES file for details. Corrected an error in the logtalk.css CSS file. Modified the definitions of predicates lgt_file_extension/2 and lgt_file_name/2 in all config files. Updated all the user manual sessions related to automatic documentation. Updated all HTML documentation for future XHTML 1.0 conformance. Start adding documenting directives to most examples. 2.6.0 - April 27, 2000 Added support for documentation of objects, protocols, and categories, using automatic generation of XML files. Added info/1 and info/2 directives for documenting objects, protocols, categories, and predicates. Added definition of documentation file name extension and default file names for the DTD and XSL files to the config files. Improved error checking for the built-in predicates create_object/4, create_protocol/3 and create_category/4 to also detect invalid entity identifiers. Updated the user and reference manuals to describe the new automatic documenting features. Updated all HTML documentation to conform to HTML 4.01 strict standard. Corrected some wrong cross-reference links and titles in the reference and user manuals HTML pages. PDF versions of the manuals and tutorial are now available in both A4 and US letter formats. Corrected two errors in the searching example, one in the definition of the farmer problem state space and the other when backtracking over performance reports. 2.5.2 - March 7, 2000 Updated manuals to clarify some limitations of declaring and defining dynamic predicates inside categories and documented a way of using the built-in local method this/1 to access object parameters. Removed references to parametric categories from the Logtalk documentation (at runtime we can only access object parameters, not category parameters). Corrected two wrong declarations of built-in methods (forall/2 and retractall/1) in the Logtalk pre-processor. Corrected bug where predicates declared in dynamic entities may have a "static" instead of a "dynamic" property. Corrected a bug in category compilation that prevented a dynamic category from being abolished. Speedup predicate definition lookups for categories. 2.5.1 - February 18, 2000 Two new examples: birds, a bird identification expert system adopted (with permission) from an Amzi example, and viewpoints, a set of prototypes showing how to do property sharing and value sharing in Logtalk. Renamed config file yap421.config to yap430.config to match the name of the new YAP 4.3.0 public release (named 4.2.1 while on beta testing). Partial config file for Trinc Prolog R3. 2.5.0 - December 29, 1999 The Logtalk pre-processor now accepts arbitrary clauses and directives to appear in a file before an opening entity directive. The clauses and directives are added unchanged to the compiled file. Improved performance for all kinds of message sending. Two new examples: reflection, showing how to implement a simple class-based reflective system, and symdiff, showing how to use parametric objects to implement symbolic expression differentiation and simplification. Updated config file for the beta 8 release of SWI-Prolog 3.3.0. 2.4.0 - December 1, 1999 Logtalk is now an Open Source project, available under Perl's Artistic license. Two new examples: instmethods, ilustrating the use of instance defined methods, and classvars, showing how to implement class variables. Updated Logtalk grammar to explicitly allow for user-defined types in mode/2 directives. New config files for SWI-Prolog 3.3.0, SICStus Prolog 3.8 and CIAO Prolog 1.4p0 (incomplete). Updated config file for B-Prolog 4.0. Updated config file for GNU Prolog to use the new call_with_args() built-in predicate added in version 1.1.0. Updated config file for YAP Prolog to use the new call_with_args() built-in predicate added in version 4.2.1. 2.3.1 - September 22, 1999 Logtalk pre-processor updated to only report one warning per redefined Logtalk or Prolog built-in predicate. Changed some occurrences of atom "public" to "(public)" in compiler/logtalk.pl file to avoid syntax errors in Prolog compilers (like BinProlog) that define "public" as an operator. Also put some terms between ()'s to avoid syntax errors with ALS Prolog 3.1 Update config file for ALS Prolog to work with version 3.1. Updated configs/NOTES file include a workaround to use Logtalk with XSB 2.0, some guidelines on how to write loader utility files for BinProlog 7.50, and a bug in ALS Prolog 3.1 that affects Logtalk. 2.3.0 - September 12, 1999 Metapredicate information is now stored with the other predicate properties, instead of being discarded after compiling the clauses of a metapredicate. Added predicate property metapredicate/1. It is now possible to assert clauses for dynamic metapredicates. Corrected a bug in the processing of metacalls in pseudo-object user. Corrected a bug in the implementation of private inheritance. Improved performance of protected inheritance. Corrected failure of processing initialization/1 and op/3 directives in create_object/4, create_category/4 and create_protocol/3 built-in predicates. Corrected a bug when calling private static category predicates from importing objects. Simplified code generated for categories. Rewrite code for the built-in method current_predicate/1 to avoid duplicated or wrong results when overriding predicate declarations and to ensure that all possible argument type errors are detected. Changed compilation of classes that do not instantiate any (meta)class in order to throw the correct exception when a message is sent to them. Changed compilation of root objects (that do not instantiate, specialize or extend other objects) so that calls to "super" (^^/1) fail (as they should) instead of generating a "predicate does not exist" error message. Changed implementation of "super" calls (^^/1) to avoid a potential endless loop problem when using these calls from the inheritance root object of a reflexive class-based systems. Pre-processor now checks for callable and object identifier errors. Runtime now checks for non-instantiated messages. Added new example (inheritance) about public, protected and private inheritance. Updated metapredicates, lo, kernel, and types examples. Most of the code in the last two examples is being updated to form the basis of an upcoming Logtalk standard library. Small changes in the pre-processor/runtime code for compatibility with ECLiPSe 4.2.2. Updated config files for this Prolog compiler. Rewrite some predicates in the config files for SWI-Prolog and LPA Mac & WIN Prologs for improved performance. New tutorial session about events and monitors. Updated documentation to match the changes made in this version. 2.2.0 - July 10, 1999 Implemented public, protected and private object inheritance, protocol implementation and category importation. New Logtalk built-in predicates instantiates_class/3, extends_object/3, extends_protocol/3, specializes_class/3, imports_category/3 and implements_protocol/3. The third argument returns the relation scope. Pre-processor now checks most directive errors. Changed ^^/1 (super call) implementation to only allow the use of a single predicate call for argument and to retain the original sender of the message (see the updated sicstus example). Fixed bug that prevented directives with a variable number of arguments (like dynamic(), public(), uses(), ...) being recognized. Changed definition of predicate read_term/3 in the configs files of Amzi!, Aquarius, Arity, Eclipse, IC, K, LPA Mac&WIN, Master and XSB to always instantiates the singleton variables list to the empty list. Needed to prevent backtracking problems in logtalk_load/1 and logtalk_compile/1 predicates. Removed choice-point in processing metacalls in predicate definitions. A banner with the Logtalk version is printed after loading the runtime/ pre-processor. Removed variables example. The category attributes is now part of the kernel example. Corrected some warmless syntax errors in directives in kernel/attributes.lgt, kernel/monitor.lgt and miscellaneous/queens.lgt. Changed name of blocks example to bricks and object "block" to "brick" in order to avoid problems with some Prolog compilers that use the atom "block" for operators or built-in predicates. 2.1.0 - May 11, 1999 Fixed some bugs in the definition of the pseudo-object user when sending the message predicate_property/2. Renamed config file for Calypso to GNU Prolog. New config file for LPA WinProlog 4.0. Corrected the omission in the documentation of the Logtalk grammar of the built_in entity property. New tutorial pages about building reflective class-based systems. Modified pre-processor to compile throw/1 as a control structure to ensure compatibility with the GNU-Prolog compiler. Modified pre-processor to ensure compatibility with Prolog compilers that use immediate update semantics instead of the ISO logical database update. Improved simplification of compiled object and category clauses. Rewrite and clean up pre-processor code for better compiler performance. Several updates to the examples files. Changed all example loader files to wrap the call to logtalk_load/1 inside an initialization/1 directive for ISO standard compliance. 2.0 GM - February 9, 1999 Removed some redundant choice-points that are being created when compiling Logtalk entities. Small compilation speed optimizations. Logtalk compiled files now contain the declarations for the message sending operators to ensure compatibility with some Prolog compilers. Changed the way Logtalk pre-processor writes directives to ensure compatibility with some Prolog compilers. Corrected a bug in the processing of the op/3 directive. Updated PrologII+ config file for version 4.5. Changed the definitions of catch/3 and throw/1 in the config files for LPA Prolog compilers. New config file for MasterProlog 4.1; removed config file for the old BIM Prolog 4.0. Corrected an error in the config file for OpenProlog in the definiton of the write_term/3 predicate. Added a safer definition for write_term/3 predicate in the config files for Amzi, Aquarius, Arity, Eclipse, IC, K, LPA Mac, LPA Win, and XSB Prolog compilers. Added a QUICK_START file. 2.0 Beta 3 - February 1, 1999 Closed some encapsulation holes in the implementation of super calls. Changed Logtalk pre-processor to use write_term/3 instead of write/2 and writeq/2 to workaround some compatibility problems with some Prolog compilers. Changed mode operators priority and type to be compatible with the ISO standard. Modified definition of predicate read_term/3 in the config file for Amzi compiler to return the atom end_of_file instead of '!EOF' at the end of a file (this prevented Logtalk to complete compilation any file under this compiler). Improved detection of built-in predicates while compiling. Removed config file for wamcc. This compiler have been replaced by Calypso (developed by the same author). Updated K-Prolog config file for version 4.50. Improved documentation of template config file. Added SCRIPT files to the kernel and types examples. Updated Tutorial and User and Reference Manuals. New end user license. 2.0 Beta 2 - November 16, 1998 Built-ins logtalk_compile/1 and logtalk_load/1 updated to match the documentation regarding thrown errors and to accept a list of entities to compile/load. Modified the examples loader utility files to make only a call to logtalk_load/1 by using a list of entities. This should make it easy to modify these files for compilers that don't support arbritrary queries in a file. Logtalk runtime no longer tries to catch some of the errors thrown by ::/2. Added to all config files a Logtalk predicate to check if a file exists in the current working directory (used by the logtalk_load/1 and logtalk_compile/1 Logtalk built-in predicates). New configs files for the K-Prolog 4.14 and Calypso 1.0b6 Prolog compilers. Completed the config file for Open Prolog 1.03d38 (with the exception of lgt_current_date/3 that still have a dummy definition). Added a missing definition for Logtalk predicate forall/2 to the config file for Prolog II+ 4.4. Modified Logtalk pre-processor/runtime to avoid syntax errors when running on Open Prolog or Calypso and to remove some redundant choice-points that are being created when compiling categories and protocols. Modified some examples that use operators to avoid syntax errors in some Prolog compilers. Modified the implementation of the built-in method predicate_property/2 to avoid duplicate answers and to throw an instantiation error if the first argument is not bound. Modified definition of the pseudo-object user to hide Logtalk pre- processor predicates from the current_predicate/1 built-in method and to ensure that the predicate_property/2 built-in method returns Logtalk defined predicate properties for built-in Logtalk and Prolog predicates. Modified Prolog code generated by the pre-processor to further minimize possible conflicts with user defined predicates. Added a lgt_predicate_property/2 predicate to the config files to improve Logtalk portability. Updated Tutorial and User and Reference Manuals. 2.0 Beta 1 - October 18, 1998 Added basic support for implementation multi-inheritance. Logtalk pre-processor updated to try to detect misspelt local predicate calls. First public beta. 2.0 Alpha 1 - July, 1998 First release for registered users.