Visual Prolog

Visual Prolog is a strongly typed, object oriented extension of the Prolog logic programming language, supporting logical, functional, object oriented, imperative, declarative, generic and concurrent programming within a single language. It originated as Turbo Prolog, first released by Borland with version 1.0 in 1986 and version 2.0 in 1988, before development passed to the Danish company PDC, which renamed the product Visual Prolog and has continued developing and marketing it since. Unlike standard Prolog implementations, Visual Prolog uses static, strong typing with type inference, which lets the compiler catch many classes of programming errors at compile time rather than leaving them to appear only when a program runs, while still preserving Prolog's underlying logic programming model of facts, rules and unification based queries. The language's compiler generates native x86 and x86-64 machine code, and Visual Prolog runs on Windows, where it is used to build graphical user interface applications, console programs, dynamic link libraries and CGI programs. Visual Prolog remains proprietary, commercially licensed software, with its most recent stable release, version 11 build 1105, published in January 2024, reflecting continued active maintenance of the language and its development environment by PDC.