<P> A fifth - generation programming language (5GL) is a programming language based on solving using constraints given to the program, rather than using an algorithm written by a programmer . Most constraint - based and logic programming languages and some other declarative languages are fifth - generation languages . </P> <P> While fourth - generation programming languages are designed to build specific programs, fifth - generation languages are designed to make the computer solve a given problem without the programmer . This way, the user only needs to worry about what problems need to be solved and what conditions need to be met, without worrying about how to implement a routine or algorithm to solve them . Fifth - generation languages are used mainly in artificial intelligence research . Prolog, OPS5 and Mercury are examples of fifth - generation languages . </P> <P> These types of languages were also built upon Lisp, many originating on the Lisp machine, such as ICAD . Then, there are many frame languages, such as KL - ONE . </P> <P> In the 1980s, fifth - generation languages were considered to be the way of the future, and some predicted that they would replace all other languages for system development, with the exception of low - level languages . Most notably, from 1982 to 1993, Japan put much research and money into their fifth - generation computer systems project, hoping to design a massive computer network of machines using these tools . </P>

What are the unique features of fifth generation languages