Yay! There is now pl/scheme, a PostgreSQL procedural language handler for the Scheme programming language, specifically GNU Guile .

This allows implementing database stored procedures in Scheme.

It's a bit underdocumented at this point; it is not clearly documented how database parameters are passed into the Scheme level. The examples don't use Scheme functions; they instead use let structures, which is definitely more interesting...

What is also unclear is what the interaction between the database engine and the Guile interpreter is; open questions would include:

• Does it spawn a separate instance for each backend?
• Where does shared code reside, if anywhere?

It points me to wanting to get a PL/CLISP going...