Type Programming language Website www.visual-prolog.com | License Proprietary | |
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Developer(s) Prolog Development Center Stable release 7.5, Build 7502 / November 5, 2015; 16 months ago (2015-11-05) Operating system | ||
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.
Contents
- Brief Release History
- Hanoi Example
- Reception
- Visual Prolog Video Tutorials
- Books about Visual Prolog
- References
Logic languages are traditionally interpreted, but Visual Prolog is compiled. 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 7.5 contains http server and LALR(1) parser generator (see also New Features in Visual Prolog 7.5).
Version 7.4 can generate 64 bit windows code (see also New Features in Visual Prolog 7.4).
Version 7.3 introduced generic classes and interfaces (see Generic programming), guarded monitors (see also New Features in Visual Prolog 7.3).
Version 7.2 introduced anonymous predicates (a logical pendant to anonymous functions) and namespaces (see also New Features in Visual Prolog 7.2).
Version 7.0 introduced parametric polymorphism.
Since version 6.0 the language has been fully object-oriented.
Hanoi Example
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.
Reception
BYTE in 1989 listed Turbo Prolog 2.0 as among the "Distinction" winners of the BYTE Awards, approving of how Borland had "developed a system for real-world applications programming".