<\/span><\/h2>\n\n\n\nThere are many logic programming languages and some of them are used extensively in practical use. The following table will help you compare these.<\/p>\n\n\n\nLanguage <\/strong><\/td>Year <\/strong><\/td>Main Use <\/strong><\/td>Difficulty <\/strong><\/td><\/tr>Prolog <\/td> 1972 <\/td> AI, NLP, expert systems <\/td> Difficulty <\/td><\/tr> Datalog <\/td> 1980s <\/td> Databases, queries, analysis <\/td> Easy to medium <\/td><\/tr> Mercury <\/td> 1995 <\/td> Large, fast systems <\/td> Hard <\/td><\/tr> Answer Set Programming (Clingo) <\/td> 1990s <\/td> Puzzles, planning, scheduling <\/td> Medium <\/td><\/tr> Curry <\/td> 1990s <\/td> Mixing logic and functional code <\/td> Hard <\/td><\/tr> Oz <\/td> 1990s <\/td> Teaching, research <\/td> Hard <\/td><\/tr> G\u00f6del <\/td> 1990s <\/td> Research <\/td> Hard <\/td><\/tr> ECLiPSe <\/td> 1990s <\/td> Constraint solving <\/td> Medium <\/td><\/tr> Visual Prolog <\/td> 1980s <\/td> Windows desktop apps <\/td> Medium <\/td><\/tr> miniKanren <\/td> 2000s <\/td> Research, embedded in Scheme\/Clojure <\/td> Medium <\/td><\/tr> \u03bbProlog <\/td> 1980s <\/td> Theorem proving, higher-order logic <\/td> Hard <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<\/span>One of the Logic Programming Languages Is Prolog<\/strong><\/span><\/h2>\n\n\n\nOne of the logic programming languages is Prolog and if you choose to learn only one, this is it. It appeared in 1972 primarily due to Alain Colmerauer and Philippe Roussel in Marseille (France). There was also much influence from Robert Kowalski’s concepts of using logic to program. Their original goal was to make computers “understand” natural language, and the beginnings of Prolog were that.<\/p>\n\n\n\n
So how did it gain such popularity after 50+ years? A few reasons. The concepts are straightforward to grasp, and there are countless tutorials and books available, and for rule problems, it can still be as compact as ten lines in a language that takes a hundred. It has also been the primary language used for a great deal of AI and NLP research, hence a long history of use.<\/p>\n\n\n\n
If you still wish to try, then here are two popular versions:<\/p>\n\n\n\n
\nSWI-Prolog:<\/strong> Free, easy to install, and is very well documented. This one would be my first choice.<\/li>\n\n\n\nGNU Prolog:<\/strong> Smaller and fast, and can convert your code to a standalone program.<\/li>\n<\/ul>\n\n\n\n<\/span>Examples of Logic Programming Languages<\/strong><\/span><\/h2>\n\n\n\nIt’s easy to read about logic programming languages, but watching the code is much faster. So, let’s take a look at some examples of logic programming languages at work. I’ve made each one of them small on purpose.<\/p>\n\n\n\n
<\/span>Prolog: A Simple Family Tree<\/strong><\/span><\/h3>\n\n\n\nparent(tom, sam).The first two lines are true statements. Tom is Sam’s father and Sam is Lisa’s father.Tom is the father of Sam and Sam is the father of Lisa. The third line is a \u201crule\u201d and the :- means \u201cif.\u201d If X is a parent of Y and Y is a parent of Z, then X is a grandparent of Z. The last line is the question. Prolog answers Who = lisa. No one made it look nice, it just did.<\/p>\n\n\n\n
<\/span>Datalog: Querying Data<\/strong><\/span><\/h3>\n\n\n\nparent(tom, sam).This is very similar to Prolog, and that’s not a coincidence. The ancestor rule applies here, and thus, the chain continues to be followed. You would get sam and lisa back (twice). The big difference is that Datalog always terminates and provides all the answers, and for this reason people like it for databases.<\/p>\n\n\n\n
<\/span>Answer Set Programming: Graph Colouring<\/strong><\/span><\/h3>\n\n\n\ncolor(red). color(green). color(blue).This one is a bit special. The nodes, edges and colours are listed. Then you say that each node will have a single colour and no two node can have the same colour if they are connected. Then a solver such as Clingo can find colourings that satisfy those rules. Ideal for plotting out puzzles and planning tasks.<\/p>\n\n\n\n
<\/span>Mercury: Prolog\u2019s Stricter Cousin<\/strong><\/span><\/h3>\n\n\n\n:- pred grandparent(person::in, person::out) is nondet.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nMercury is similar to Prolog, except that types must be declared and the input and output arguments must be specified. In the beginning, it is an additional task, but it is not. The trade off is that the compiler will find errors early, and the resulting code will execute much faster, which is why it’s good for larger systems.<\/p>\n\n\n\n
<\/span>Best Logic Programming Languages in 2026<\/strong><\/span><\/h2>\n\n\n\nChoosing the optimal logic programming language is very much dependent on the application that you’re trying to construct. The same language that works well with a student project may not be suitable for a large production system. So here are 7 to know with a brief word on who they are for.<\/p>\n\n\n\n
<\/span>1. Prolog (SWI-Prolog)<\/strong><\/span><\/h3>\n\n\n\nIt is the classic and, again, the easiest place to start, which is Prolog. You fill in the facts and rules, then ask questions and it will hunt down the answers. Most people use the version referred to as SWI-Prolog, which is free, friendly, and well documented.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nReadily understandable syntax that is easy to learn.<\/li>\n\n\n\n A large library of tutorials, books and community assistance.<\/li>\n\n\n\n Expert systems, AI, NLP are strong abilities.<\/li>\n<\/ul>\n\n\n\nBest for:<\/strong> Beginners and rule-based AI projects.<\/p>\n\n\n\n<\/span>2. Datalog<\/strong><\/span><\/h3>\n\n\n\nDatalog is a stripped down Prolog, tailored for data. Less flexible, which is the goal! Queries are guaranteed to terminate and recursive queries such as \u201cwho are all the ancestors?\u201d work quite nicely. It is used as the basis for many modern analysis tools.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nAny query always receives complete answers.<\/li>\n\n\n\n Great at recursive data relationships<\/li>\n\n\n\n Easy to understand even by people who do not know SQL.<\/li>\n<\/ul>\n\n\n\nBest for:<\/strong> Databases, program analysis, and knowledge graphs.<\/p>\n\n\n\n<\/span>3. Mercury<\/strong><\/span><\/h3>\n\n\n\nProlog adds strict types and modes to Mercury’s ideas. Yes, it’s harder to write, but the compiler can catch many of the bugs before you run anything. The code also is much faster than most Prolog programs.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nRobust static typing and typing modes checking.<\/li>\n\n\n\n Fast compiled code<\/li>\n\n\n\n Designed to support large and long-lived systems<\/li>\n<\/ul>\n\n\n\nBest for:<\/strong> Performance-heavy and large-scale projects.<\/p>\n\n\n\n<\/span>4. Answer Set Programming (Clingo)<\/strong><\/span><\/h3>\n\n\n\nASP is slightly different to Prolog. You state the problem’s rules and restrictions, and a solver such as Clingo will search for all solutions that conform to them. Excellent at problems involving hard puzzles where one might otherwise code a lot of searches.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nOne, many or the best solution(s) are discovered by solvers.<\/li>\n\n\n\n Solves difficult combinatorial problems<\/li>\n\n\n\n Concise problem statements.<\/li>\n<\/ul>\n\n\n\nBest for:<\/strong> Scheduling, planning, and puzzles.<\/p>\n\n\n\n<\/span>5. ECLiPSe<\/strong><\/span><\/h3>\n\n\n\nECLiPSe is a hybrid of Prolog and constraint programming. You don’t have to try them all, you just define some constraints, such as \u201cthese two tasks may not overlap\u201d, and it quickly whittles them down. It’s not as well known but very useful for optimisation tasks.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nBuilt-in constraint solvers<\/li>\n\n\n\n Good for optimization problems<\/li>\n\n\n\n Prolog-style syntax, so it is familiar.<\/li>\n<\/ul>\n\n\n\nBest for:<\/strong> Resource allocation and logistics.<\/p>\n\n\n\n<\/span>6. miniKanren<\/strong><\/span><\/h3>\n\n\n\nminiKanren is a very small logic language that is embedded in other languages, primarily Scheme and Clojure. Programs can be \u201cbackwards,\u201d which may sound strange, but actually is quite fun! It is a favorite with those who like to research and try out new things.<\/p>\n\n\n\n
Key features:<\/strong><\/p>\n\n\n\n\nIncorporates words into foreign languages that you are familiar with<\/li>\n\n\n\n Very small and easy to understand<\/li>\n\n\n\n Provides two-way relations.<\/li>\n<\/ul>\n\n\n\n