OPS5

OPS5 is a rule-based programming language designed in the early 1970s by Charles Forgy while working on his PhD at Carnegie Mellon University. It is widely considered to be the first production rule system, and inspired a number of later rule-based languages such as CLIPS, JESS, and Drools. OPS5 was designed to be a more user-friendly and powerful alternative to the then-popular Lisp programming language. It was intended to allow programmers to easily write and maintain programs that could make decisions based on a set of rules. Forgy based the syntax of OPS5 on that of Lisp, but made a number of important changes. Most notably, he replaced Lisp's S-expression syntax with a more traditional infix notation. This made OPS5 programs much easier to read and write, and also allowed for the use of standard arithmetic operators. OPS5 programs are composed of a set of rules. Each rule has a condition and an action. When the condition of a rule is met, the action is executed. This allows for programs to make decisions and take actions based on a set of conditions. OPS5 is a powerful and expressive language that is well suited for a wide variety of applications. It is particularly well suited for artificial intelligence and expert systems.