root/tags/lgt291/RELEASE_NOTES

=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.9.1

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


RELEASE NOTES
=============


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.