Arity/Prolog

A Prolog development system from USA based Arity Corporation initially supplied in 1985 for DOS with a version for 16 bit OS/2 following a few years after.

History
These 16 bit systems were sold on a modular basis, you could start out by buying an interpreter, then add a compiler, SQL Server, expert system and so on. The Arity/Prolog system differed somewhat from their competitors offerings in that while it offered an interpreter it was primarily sold as a compiler allowing you to write and debug your applications in the interpreter and then deliver a compiled executable. Arity/Prolog also had a built in database system, this is not uncommon (and Prolog itself can be viewed as a database of sorts) but the Arity version had a slightly stronger version than usual and the company actually sold a SQL front-end to their database. But a database is also often used on PC Prolog compilers since this helps with compilation, instead of doing backtracking the compiler cheats by looking the value up in a database. Unlike competitor Prolog Development Center, Arity choose not to change the language to facilitate easier compilation but rather provided a Clocksin and Mellish superset. This meant that while their compilers created faster programs than interpreted Prolog, it never managed to reach the speed of Visual Prolog but had a much higher compatibility with traditional Prolog software. However it was not fully compatible with "standard" Prolog and failed some Prolog compatibility and speed tests. This may have been one of the factors why the compiler module was re-written from the ground up for 32 bit mode.

Note also that there are 2 different versions of "Windows modules" that were sold for the 16 bit versions of Arity/Prolog. The more common one was an add-on module/library that allowed DOS and OS/2 text mode programs to have their own windowing systems not unlike what products like Turbo Pascal offered, and on the other hand Arity made a deal with Microsoft to deliver a version of their toolkit for version 1 of Windows: It does appears that a Windows compatible interpreter was delivered and later updated to support Windows 2.x and 3.x, but it seems to have only limited if any predicate support for Windows development proper, being more of an alternative to a text window.

Versions

 * 6.0.39 (1991) - for 16 bit OS/2 and DOS

Links

 * GitHub page - Mostly empty when this was written


 * Articles
 * A review of Arity/Prolog for DOS from 1986 - By PC Magazine