Amzi! 4.1 Release

This file documents the changes introduced in the 4.1 Amzi! release. The **'d items may require source code changes.

New Features

Delphi 3.0 Support - The Delphi Component has been upgraded to work in a package for version 3.0 and the extended predicate support has been modified to support version 3.0. All the Delphi samples have been upgraded to 3.0, and the Prolog Expert System (ProXS) and Sports Scheduler (SSched) have been added.

Borland C++ Builder Support - The Amzi! Logic Server now supports Borland's new C++ Builder. See the new hello program in \AMZI4\SAMPLES\CPP\HELLO\BORLAND C++ BUILDER.

Visual Basic 5.0 and Extended Predicate Support - The VB module now supports extended predicates so that Amzi! Prolog modules can call functions written in VB 5.0. A sample demonstrating this has been added, and the remaining VB samples have been upgraded to 5.0.

Multifile and Discontiguous Support - It is no longer required to have all of the clauses for a compiled predicate to be either discontiguous or in the same file. This applies both to consulted source files and loaded compiled files. However, the directive 'multifile' must be added to the top of the file for clause that will be defined in multiple files, and/or 'discontiguous' for discontiguous clauses in the same file.

PLM Unload - It is now possible to unload all the clauses previously loaded from a PLM file by using unload/1. This feature, along with the multifile feature, makes it possible to create applications that dynamically load and unload .PLM files containing definitions of the same predicates. For example, a technical support expert system might have a predicate called rule/3 which is defined in separate files for printer problems and video monitor problems. The system can dynamically load the correct .plm file and unload it when done, waiting for the next problem.

Removed Support for WinCGI ** - The CGI interface has been greatly simplified by removing support for the Windows CGI quasi-standard in favor of the widely support Standard CGI interface.

Projects Use Relative Pathnames - Prolog projects now use relative pathnames for files located in or below the project directory. This makes them much each to move to other computers.

ODBC Supports Floats/Doubles and Sample Demonstrates Dates/Times - The ODBC LSX has been enhanced to support floating point and double fields (type specifiers f and g). A new sample, Events, illustrates the use of date and time fields.

cSTR and cATOM are Set Properly for ASCII and Unicode - When using the LSAPI constants cSTR and cATOM, theywill be automatically mapped to cASTR and cAATOM. for ASCII implementations and cWSTR and cWATOM for Unicode (wide) implementation.

Strings and Atoms Unify with Each Other - A term containing strings that have the same values as atoms in another term will unify. This makes it easier to interface with databases using ODBC.

New Predicate curdir/1 - curdir/1 returns the current directory as a string and is included in A4WIN.LSX which must be loaded before curdir/1 can be used.

New Predicate chdir/1 - chdir/1 succeeds if it can change to the directory specified by the string, atom or character list passed to it. This predicate is included in A4WIN.LSX, which must be loaded before the chdir/1 can be used.

Bug Fixes

Visual Basic Functions Return True/False and Types Have Changed**

Visual Basic Declarations Modified from Integers to Longs - Most of the LSAPI functions that passed integers have been changed to longs to match the parameter types properly. In general, programs will work under the IDE with the old definitions, but not as stand-alone EXEs.

Operator Precedences Conform to ISO Standard - The precedences of Prolog operators in Amzi! now match the ISO standard. This affects the following operators: - ** @ : \.

IDE Save As Defaults to .PRO - The File/Save As command in the Windows IDE now automatically adds a 'pro' suffix if none is specified.

Fixed findfiles/3 - Under Windows 95, findfiles stopped working. Under NT it was returning incorrect file dates/times. Both problems have been fixed.

Known Limitations

Field Order in ODBC matters

New Features

Java 1.1 Support

The Amzi! Java Interface has been rewritten to use the Java Development Kit (JDK) 1.1 Java Native Interface (JNI). The 1.1 JNI is a much improved, much cleaner API for integrating Java code with non-Java applications, but the change is internal and does not greatly affect the external specification of the Amzi! Java Logic Server class. The full source code for the interface, including both the Java source and the interface DLL source, is available in the amzi4\source\java11 directory.

(Note: Microsoft's Java does not, at this writing, support the 1.1 JNI, however, Java still supports the old-style Java native methods used in the Amzi! 1.0 Java interface. For this reason, and to continue support for JDK 1.0 applications, Amzi! will continue to distribute its 1.0 Java interface as well.)

There are some external improvements in the Amzi! Java Interface as well:

Support for extended predicates - You can now create extensions to Prolog written in Java, letting you write Prolog code that can access any of the capabilities of Java. See the documenation on AddPred and the various parameter handling Logic Server API functions.
Improved exception handling - The methods for getting detailed information about Logic Server exceptions are now part of the LSException class, rather than the LogicServer class. The number of error handling methods has been increased as well, to provide information about read errors and the Prolog call stack.

Extended Predicates for Visual Basic 5.0

The VB module now supports extended predicates so that Amzi! Prolog modules can call functions written in VB 5.0. The VB module now includes functions for definining and implementing extended predicates. A simple example is given in SAMPLES/VB/EXTPRED.

Multifile and Discontiguous Support

The ISO standard defines two directives that can be used to let the compiler know that the clauses of a predicate are discontiguous in the same file and/or that the clauses of a predicate might be defined in multiple files. The directives are discontiguous and multifile. As far as the Amzi! compiler is concerned, it does the same work for either directive, so the two may be used interchangably, and it is not necessary to use both for predicates whose clauses are both discontiguous and multifile. However, both directives are supported for compatibility with the ISO standard and other Prolog that support both.

For example, if the clauses of the predicate duck/1 are discontiguous within a file, then add the directive:

:- discontiguous duck/1.

If you want to define the duck/1 predicate in other files, then each file should have the directive:

:- multifile duck/1.

This feature is especially useful for those situations where you might have multiple source files defining the same predicate for different situations. These can be separately compiled and the PLM files loaded on demand by the main application.

PLM Unload

A new predicate unload/1 has been added to remove all clauses from a previously loaded PLM file. The filename passed to unload/1 must be the same as the filename specified in load/1.

Removed Support for WinCGI

The CGI interface has been greatly simplified by removing support for the Windows CGI quasi-standard in favor of the widely support Standard CGI interface. Also, the Standard CGI variable names have been adopted. This means all Prolog scripts that reference those variables will need to be updated, or you can #define WINCGI_NAMES in AMZICGI.C to use the same Windows CGI variables names that were used previously.

Bug Fixes

Visual Basic Functions Return True/False and Types Have Changed

Functions that return the special VB value 'True' or 'False' are now declared as booleans instead of integers. If your code follows these conventions, no changes will be needed. If you use '1' and '0' instead, those values will need to be changed to 'True' and 'False'.

Some Visual Basic programs ran differently under the Developer Studio as compared with a stand-alone program. These problems were caused by some type mismatches between AMZI4.BAS and AMZI4.DLL. As a result, bINT and bSHORT are now defined the same; as 16-bit values. Functions that used to return integers now return longs, and arities are now bytes.