rogersm.net » lisp

Understanding lisp conditions

rogersm — Fri, 24 Jul 2009 09:06:50 +0000

If you ever have trouble understanding lisp conditions (what other languages call exceptions) or you have no experience with lisp and want to discover an exception system where you can jump from program code to the exception handling code and back (restart) read the following articles:

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

When CL-Interpol is too big for your needs…

rogersm — Wed, 18 Feb 2009 13:35:34 +0000

…you can use this port of Perl’s qq to 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.

Qitab is the first ITA project

rogersm — Mon, 12 Jan 2009 09:45:16 +0000

As a follow up of my previous post:

Qitab is the final name of the project ITA will use to publish its lisp code.

The first project in Qitab is POIU a replacement for ASDF that will compile each of your ASDF systems in parallel.

Also, ITA published XCVB, a compillation tool for SBCL. Zach wrote a post about it in May.

ITA Software will release code

rogersm — Wed, 07 Jan 2009 13:17:52 +0000

ITA Software, Inc, will start distributing code the the Free Software world. They created a project in common-lisp.net site to start adding projects during 2009.

ITA is known in lisp world for being a proud user of lisp in software development world, and contributing to existing lisp projects (from SBCL to slime). They’re also vocal about lisp use in today’s most complex problems (low fare search engine is one of their business) so they’re widely respected.

They will be publishing generally purpose libraries and utilities. No Airline Industry code will be published.

Additional information will be found in the devel and announce mailing lists.

Update: ITA has changed the project name, more information in the following post.

Two libraries for multi-threaded lisp programming

rogersm — Thu, 30 Oct 2008 14:18:59 +0000

Pcall

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.