Gambit-C 4.0

Gambit-C 4.0 is available! It's still a beta release, but knowing Marc Feeley personally, it wouldn't be out if he wasn't really confident about the stability of the whole system.

This new version offers lots of improvements over the previous release (3.0). But there are two noteworthy new features in this release:

• very efficient threads (I already wrote about them here), and
  
• unusual use of ports to represent some data structures, like directories, server sockets, FIFOs, etc.
  

Let me give an example of the latter. In Gambit-C 4.0, server sockets are created using the open-tcp-server procedure. This procedure, when invoked on a TCP port number, returns an (input) server port. When one attempts to read from this port, it blocks until a client connects to the server. The value returned by read is a bidirectional port that allows the application to communicate with the client. More concretely, here is how one writes a client-server application in Gambit-C:

(define *server-port* 8080)



(define (run-server)

  (let ((server-port (open-tcp-server *server-port*)))

    (let loop ()

      (let ((connection (read server-port)))

        (process-connection connection)

        (loop)))))



(define (process-connection connection)

  (let ((request (read-line connection)))

    (process-request request connection)

    (close-port connection)))

In other words, ports are used as a generalized iteration mechanism. That's very cool.

Gambit-C has always been my favorite Scheme implementation, for a number of reasons (exceptional debugging support being the first). Now that it is released under the Apache license, it's more appealing than ever to use it in a commercial setting. I'm sure it will gain a new momentum in the Scheme community.