Clolog is a small, experimental logic programming language implemented in Clojure. It aims to bring the declarative power of Prolog to Clojure, allowing developers to define facts and rules, and then query those facts and rules using logical inference. Clolog supports basic Prolog features such as unification, backtracking, and recursion, and integrates seamlessly with existing Clojure code and data structures. While it's not a full-fledged Prolog implementation, it provides a lightweight and accessible way to experiment with logic programming within the Clojure ecosystem.
Bob Schrag's "Clolog," hosted on GitHub, presents a novel approach to logic programming within the Clojure ecosystem. This project endeavors to provide a lightweight and embeddable logic engine, leveraging Clojure's inherent functional programming paradigms and data structures. Rather than relying on traditional Prolog syntax or execution models, Clolog defines a declarative mini-language implemented entirely within Clojure. This approach allows developers familiar with Clojure to seamlessly integrate logic programming techniques into their existing projects without a steep learning curve or the need for external dependencies beyond the Clojure standard library.
Clolog's functionality centers around defining logical relations using Clojure functions and subsequently querying these relations with a dedicated query function. The relations themselves are represented using Clojure vectors, mirroring the structure of facts and rules typically found in Prolog. These vectors are then interpreted by the Clolog engine to establish logical connections and infer new knowledge based on the provided rules and queries. The query function facilitates the retrieval of all possible solutions satisfying the given constraints, returning them as a sequence of Clojure maps, further enhancing integration with existing Clojure code.
While inspired by Prolog, Clolog distinguishes itself by prioritizing simplicity and integration with the Clojure environment. It aims to offer a practical tool for incorporating logical reasoning into Clojure applications without the complexities often associated with full-fledged Prolog implementations. The project's concise nature and reliance on core Clojure concepts makes it an accessible and potentially powerful addition to a Clojure developer's toolkit. It offers a distinct pathway for exploring logic programming within the familiar context of Clojure, potentially opening up new avenues for problem-solving and application development.
Summary of Comments ( 43 )
https://news.ycombinator.com/item?id=43695620
HN commenters generally expressed interest in Clolog, praising its simplicity and elegance. Some highlighted its potential as a pedagogical tool for introducing logic programming concepts. Others discussed its limitations, particularly around performance and the lack of certain features found in Prolog, like cut and negation. There was a short thread comparing it to miniKanren, with a commenter pointing out Clolog's more traditional Prolog-like syntax. A few users shared their experiences experimenting with the code, including porting it to other Lisps. Overall, the reception was positive, with many appreciating the project as a clean and understandable implementation of core logic programming ideas.
The Hacker News post titled "Clolog" (https://news.ycombinator.com/item?id=43695620) discussing the Clolog project (https://github.com/bobschrag/clolog) has several comments exploring various aspects of the project and its implications.
One commenter highlights the historical context of logic programming within Lisp, mentioning the development of the LOGLISP system in the early 1980s and its integration of logic programming paradigms into a Lisp environment. They also touch upon the challenges of efficiently implementing such systems, especially considering the performance limitations of hardware at the time.
Another commenter expresses their intrigue with the project, particularly the choice of Clojure as the implementation language. They appreciate the elegance of Clojure and suggest that it might provide a suitable foundation for a logic programming system. They also inquire about the project's performance characteristics and the author's motivations for choosing Clojure.
A subsequent comment raises the question of the project's practical applications and expresses curiosity about the types of problems it is designed to solve. They seem to be looking for concrete examples or use cases to better understand the scope and potential of Clolog.
Further down, a commenter delves deeper into the technical aspects of the project, specifically discussing the unification algorithm employed by Clolog. They inquire about the chosen approach and its implications for performance and expressiveness. This comment sparks a short discussion about different unification strategies and their trade-offs.
Another commenter brings up the topic of constraint logic programming and wonders if Clolog supports or plans to support constraints. They posit that constraint programming features could significantly enhance the project's applicability to a wider range of problems.
The discussion also touches upon the broader context of logic programming and its place in the current programming landscape. One commenter laments the relative decline in popularity of logic programming and expresses hope that projects like Clolog can help revitalize interest in this paradigm.
Overall, the comments reflect a mixture of curiosity, technical analysis, and historical perspective. They explore the project's design choices, potential applications, and its relationship to the broader field of logic programming. The commenters express interest in the project's performance, the chosen unification algorithm, and the possibility of adding constraint programming features.