||This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (June 2013)|
|Developer(s)||Prolog Development Center|
|Stable release||7.5, Build 7500 / July 23, 2014|
|Operating system||MS Windows Vista/Windows 7/Windows 8|
Visual Prolog, also formerly known as PDC Prolog and Turbo Prolog, is a strongly typed object-oriented extension of Prolog. As Turbo Prolog it was marketed by Borland, but it is now developed and marketed by the Danish firm Prolog Development Center (PDC) that originally developed it. Visual Prolog can build Microsoft Windows GUI-applications, console applications, DLLs (dynamic link libraries), and CGI-programs. It can also link to COM components and to databases by means of ODBC.
Visual Prolog is compiled rather than interpreted, as is traditional for logic languages. This provides the important improvement of converting traditional Prolog-typical run-time errors to compiler warnings, which ensures a better robustness of the finished applications.
The core of Visual Prolog are Horn clauses, algebraic datatypes, pattern matching and controlled non-determinism like in traditional Prolog, but unlike traditional Prolog, Visual Prolog has always been strongly and statically typed.
Brief Release History
Version 7.4 can generate 64 bit windows code (see also New Features in Visual Prolog 7.4).
Version 7.0 introduced parametric polymorphism.
Since version 6.0 the language has been fully object-oriented.
In the 'Towers of Hanoi' example, the Prolog inference engine figures out how to move a stack of any number of progressively smaller disks, one at a time, from the left ('left') pole to the right pole ('right') in the described way, by means of a center ('center') pole as transit, so that there's never a bigger disk on top of a smaller disk. The predicate 'hanoi' takes an integer = the number of disks, as an initial argument. In real-life, Visual Prolog is especially suited for intricate problems, such as resource planning, etc. As the example shows, Visual Prolog can be used for quick 'programming in the small,' but it is mostly employed for industrial-strength large applications.
class hanoi predicates hanoi : (unsigned N). end class hanoi implement hanoi domains pole = string. clauses hanoi(N) :- move(N, "left", "centre", "right"). class predicates move : (unsigned N, pole A, pole B, pole C). clauses move(0, _, _, _) :- !. move(N, A, B, C) :- move(N-1, A, C, B), stdio::writef("move a disc from % pole to the % pole\n", A, C), move(N-1, B, A, C). end implement hanoi goal console::init(), hanoi::hanoi(4).
Visual Prolog Video Tutorials
- Hello World! | Visual Prolog | Video Tutorial demonstrates basic IDE features while creating a "Hello World!" program.
- Form Demo | Visual Prolog | Video Tutorial demonstrates how to create a form and link it to a menu item.
- IntelliSpeed | Visual Prolog | Video Tutorial demonstrates the autocompletion facility in the IDE.
Books about Visual Prolog
- Thomas W. de Boer, A Beginners Guide to Visual Prolog
- Eduardo Costa, Visual Prolog for Tyros
- Giovanni Torrero, VISUAL PROLOG PER PRINCIPIANTI Italian 113 pages (pdf)
- Logic programming
- Logtalk, object-oriented
- Mercury (programming language), static and strong typing
- Object-oriented programming