yap-6.3/Logtalk/RELEASE_NOTES

=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.8.4

Copyright (c) 1998-2001 Paulo Moura.  All Rights Reserved.
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RELEASE NOTES
=============


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.