What are the advantages of using Prolog over other languages?

Question

Every language that is being used is being used for its advantages, generally.

What are the advantages of Prolog?

What are the general situations/ category of problems where one can use Prolog more efficiently than any other language?

Answer 1

Any other language is illogical captain.

Answer 2

Compared to what exactly? Prolog is really just the pre-eminent implementation of logic programming so if your question is really about a comparison of programming paradigms well that's really very broad indeed and you should look here.

If your question is more specifically about prolog vs the more commonly seen OO languages I would argue that you're really comparing apples to oranges - the "advantage" (such as it is) is just a different way of thinking about the world, and sometimes changing the way you ask a question provides a better tool for solving a problem.

Answer 3

Basically, if your program can be stated easily as declaritive formal logic statements, Prolog (or another language in that family) will give the fastest development time. If you use a good Prolog compiler, it will also give the best performance and reliability, because the engine will have had a lot of design and development effort.

Trying to implement this kind of thing in another language tends to be a mess. The cleanest and most general solution probably involves implementing your own unification engine. Even naive implementations aren't exactly trivial, the Warren Abstract Machine has a book or two written about it, and doing better will at the very least involve a fair bit of research, reading some headache-inducing papers.

Of course in the real world, key parts of your program may benefit from Prolog, but a lot of other stuff is better handled using another language. That's why a lot of Prolog compilers can interface with, e.g., C.

Answer 4

I'd say prolog works well for problems where a knowledge base forms an important part of the solution. Especially when the knowledge structure is suited to be encoded as logical rules.

For example, writing a natural language interpreter for a particular problem domain would require a lot of knowledge in that domain. Expert systems also fall within this knowledge driven category.

It's also a nice language to explore solutions to logical puzzles ;-)

Answer 5

One of the best times to use Prolog is when you have a problem suited to solving with backtracking. And that is when you have lots of possible solutions to a problem, and perhaps you want to order them to include/exclude depending on some context. This suggests a lot of ambiguity... as in natural language processing.

It sure would be a lot tidier to write all the potential answers as Prolog clauses. With a imperative language all I think you can really do is write a giant (really giant) CASE statement, which is not too fun.