Why hasn't logic programming caught on?

Jason Baker picture Jason Baker · Mar 10, 2009 · Viewed 8.9k times · Source

As time goes by, it appears more and more like functional programming is having more of an effect on other programming languages. We're starting on Prolog in my AI class, and it seems like there are some things there that would make programming in non-AI fields easier. My question is this: why hasn't logic programming caught on in the same way?

In this topic, it seems that a general consensus was reached that logic programming is useful but must be proven as such. Is there a reason why it's not seen as useful?

Update: Perhaps I should be a bit more clear. I'm not really asking about Prolog. I can see why it wouldn't be a good idea to choose Prolog for most real-world applications.

To give an example of more what I'm talking about, consider list comprehensions/map/filter in Python. These are clearly influenced by functional languages. Why is it that languages such as Python haven't also picked up on these kinds of things from logic programming languages like they have functional languages?

Answer

Laurent picture Laurent · Mar 10, 2009

When you learn about logic-programming in Computer Science classes using Prolog, the main point is not to make you a proficient Prolog programmer, but rather to open up your mind to alternate forms of programming techniques (data-structures/algorithms) that you'd not have considered before.

To illustrate my point when I started studying Computer Science my engineering school used to require all students to write their software programs in Pascal, but since I graduated I've never used Pascal even once. But the skills I learned by picking the right data-structures and algorithms I am still using every single day.

Pascal is not showing up on my resume as a language I know, but it has been instrumental in my training as a software engineer. Its usefulness cannot only be measured by the number of line of Pascal code currently in production.

When you'll develop software you'll realize that, even though you are not writing a single line of Prolog code, you are at times re-using techniques that you may have first learned in these "useless" Prolog or AI classes you attended.

Evaluating the usefulness of a technology (specific programming language, specific software tool/application) is not simply a matter of evaluating its actual level of use, but rather its influence.

If you look at the influence logic-programming has had in the field of expert systems, computer games AI, air traffic control, and probably quite a number of other fields (suggestions anybody?) I don't think it can be said logic-programming has not caught on...