• Condition style guide by Nikodemus Siivola
• Beyond Exception Handling: Conditions and Restarts from the always great Practical Common Lisp

(defun |#q-reader| (stream sub-char numarg)
  (declare (ignore sub-char numarg))
  (let ((terminator (read-char stream)))
    (loop for ch = (read-char stream)
          until (eql ch terminator)
          collect ch into chars
          finally (return (coerce chars 'string)))))
 
(set-dispatch-macro-character
    #\# #\q #'|#q-reader|)

More information in Space Station Lambda.

You can find CL-INTERPOL in Edi Weitz’s website.

Software should be able to apply per user customization properties between common members of users’ groups. These communities should be discovered by the application using existing relationships among the users. The relationship should be an integral part of the application, set by the users (via internal application messaging, internal address book, subscription to mailing lists/interest groups…) or the application administrators (hierarchical definitions, ACLs…). From the set of communities the application should extract  customization properties and recommend the common ones to the rest of the community.

Two documents have been useful:

1. Social networks that matter: Twitter under the microscope
   is an introductory paper about choosing the right metric for identifying communities in Twitter, but easily applicable to other social networks.  Conclusion for Twitter: Number of followers is not a good metric, @friends are.

2. Discovering Communities in Linear Time: a Physics Approach is a much more interesting paper. It proposes using Kirchhoff’s laws to find communities in linear time (without the need of edge cutting). The algorithm has some drawbacks (Usha Nandini Raghavan, Reka Albert, Soundar Kumara propose an alternative), but the approach is interesting because allows to identify communities without identifying hierarchical structures.

For more social network papers, HP Labs has an interesting set of them.

Oh! I also work for an HP company, but I have no relationship to the HP Labs papers.

Just in case you read Gary Brecher’s War Nerd articles:

Exiled Online does not have a dedicated RSS feed for Gary Brecher’s articles. So, if you don’t like to go back weekly to Exile Online site or scan their whole news feed, you can use this War Nerd only RSS feed I created with Yahoo Pipes.

PCall, or parallel call, is a Common Lisp library intended to simplify ‘result-oriented’ parallelism. It uses a thread pool to concurrently run small computations without spawning a new thread. This makes it possible to exploit multiple cores without much extra fuss.

CL-STM

CL-STM is an extension of Common Lisp to support composable Software Transactional Memory. STM makes concurrent programming qualitatively better. Instead of traditional lock-based programming, you program with atomic transactions. Atomic transactions can be composed together to make larger atomic transactions. Finally, it just so happens that transactions run in parallel, and are rolled back if there are conflicts.

STM gives us freedom from deadlock, automatic roll-back on failure, and it resolves the tension between granularity and concurrency.