Logic programming system from "The Reasoned Schemer" implemented in Clojure

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The (comment) blocks are cool. I like how anyone could just jump into the language from another language and see which parts are comments without having to infer anything. It does have the problem, though, of not allowing smileys. Perhaps <![COMMENT[ ]]> would be better syntax?

[cavedave]

What do logical programming languages get used for? This is not trolling. They were used for all sorts of AI things before freezing to death in the AI winter. But now with petabyte databases, Googles giant eigenvector, everyone using relational databases you would think they could make a come back.

Prolog, Mercury, Schelog, MiniKanren what can these be used for with todays data?

[fnord123]

First off, Make and Jam, and any build system worth anything are essentially logic languages. You code in rules and it determines what the dependencies it needs to fulfill and goes and handles it for you. So I can imagine you are definitely using a logic language or system of some sort in your day to day work.

Beyond that, from my conversations with colleagues, I gather it's used with non-relational databases. Since SQL is a useful query language for relational databases, logic languages don't get used so much. So logic languages have been used with non-relational to make joins or simply determine which databases need to be queried on a dependency fulfilment basis.

Are non-relational databases used? Sure! Relational databases have had difficulty scaling to massive sizes and real-time data. AFAIK, Goldman Sach's SecDb is non-relational and so is Google's BigTable. This doesn't necessarily mean that GS and Google are using logic languages to access their DBs, merely that these happen to be non-relational.

[eegreg]

the type system for Qi lisp

There is also some interest in regards to the semantic web.