Lisp and Scheme

Grant Rettke gave this presentation at the TC Lispers Meeting in July 2009

Lisp and Scheme [tclispers] on Vimeo.

Presentation by Grant Rettke to the Twin Cities Lisp Users Group. The presentation is about Scheme for an audience more familiar with Common Lisp. 2009-07-14

Meet the Macro

Patrick Stein gave this presentation at the TC Lispers Meeting in July 2009

Meet the Macro on Vimeo.

Presentation by Patrick Stein to the Twin Cities Lisp Users Group. The presentation is an introduction to Lisp Macros. The original presentation was on 2009-07-14 but failed to record. The presentation was re-recorded on 2009-07-18.

Clojure Presentation at The Object Technology User Group Meeting

Tue, 2009-07-21 17:30 - 21:00
  • Speaker: Stuart Halloway, co-founder of Relevance, Inc
  • Date: Tuesday, July 21, 2009
  • Time: 5:30 - 9:00 PM
  • Location: University of Saint Thomas, St. Paul Campus
  • University of St. Thomas, St. Paul, MN
  • Room: TBD

This event is hosted by The Object Technology User Group.

Clojure is a Lisp dialect that runs in a Java Virtual Machine and has built-in Java interoperability. From the Clojure web page:

Clojure is a dynamic programming language that targets the Java Virtual Machine. It is designed to be a general-purpose language, combining the approachability and interactive development of a scripting language with an efficient and robust infrastructure for multithreaded programming. Clojure is a compiled language - it compiles directly to JVM bytecode, yet remains completely dynamic. Every feature supported by Clojure is supported at runtime. Clojure provides easy access to the Java frameworks, with optional type hints and type inference, to ensure that calls to Java can avoid reflection.

Clojure is a dialect of Lisp, and shares with Lisp the code-as-data philosophy and a powerful macro system. Clojure is predominantly a functional programming language, and features a rich set of immutable, persistent data structures. When mutable state is needed, Clojure offers a software transactional memory system and reactive Agent system that ensure clean, correct, multithreaded designs.

July Meeting

Tue, 2009-07-14 18:00 - 22:00
Event type: 

Schedule Updated

The next TC Lispers meeting will be Tuesday 14 July 2009. The meeting will be from 6:00pm to 8:00pm at the Common Roots Cafe on 26th St. and Lyndale Ave S. in Minneapolis. We have the room until 10:00pm, so there will be plenty of time for mingling.

The meeting topics are still being bandied about on the mailing list.  So far, we have the following four topics, each expected to run about 20 minutes:

  • "Meet the Macro" by Patrick Stein
  • "Lisp and Scheme" by Grant Rettke
  • "Hygienic Macros" by Grant Rettke
  • "SLIME introduction" by Anthony Juckel

[I have dropped my ASDF introduction for another time, since Grant is able to make it from Milwaukee this month.]

I'd like to suggest we do some business at the beginning of the meeting -- notably making any necessary arrangements for the August meeting.  Postponing business to the end seems, based on the first meeting, to be a bad tactic!  Please come with suggestions for talk topics, especially talk topics you'd like to give!

First TC Lispers Meeting A Success

Crossposted from

The first meeting of the TC Lispers group was a big success, IMO. I was figuring on an attendance near 20. My estimate is that it was really right around 40. That left us a little cramped in the meeting room at the Cafe, but we managed. We also lost the room before the presentation portion of the meeting was completely done, so there wasn’t much time for mingling. Actually, there was apparently a patio where people mingled afterward. I didn’t see this and took off too early. Mea culpa.

The presentation at this first meeting was on NST (not an abbreviation or acronym, but a sound effect /unsst/) which is a testing framework for Common Lisp. John Maraist did the presentation. He was a lively presenter, definitely had a good grasp on some dark corners of Lisp (like exactly what’s involved in the underbelly of MOP). Being a Haskell hacker though, he had some strange opinion that Lisp would be better if only it had strong typing. Well, what can you do? I mean, it’s not like he kicks puppies, I suppose. 8^)

It was great to see so many Lispers at so many levels there. About six or seven folks worked at Honeywell at some point in the past. Apparently, Honeywell had lots of Lisp development at one point. Who knew? About six or seven folks (overlapping a bit with the previous group) currently work at SIFT. There were some University students, a University teacher, some Ruby folks who wanted to see what Lisp was all about, some Lisp hobbyists, some independent consultants, some folks who can get Lisp in under the radar in their jobs, and on and on.

The next meeting is going to be 6pm on Tuesday, July 14th at the Common Roots cafe on 26th and Lyndale in Minneapolis. The topic is not quite set yet, but it seems like it might be a series of short talks on introductory aspects of Lisp.

There’s much discussion going on on the mailing list about finding a bigger venue for August and onward. There’s much discussion about exact topics for next month’s meeting. If you’re able to make it to the Twin Cities on a Tuesday evening, mark your calendars and come on out.

(assert (>= tclispers-meeting +fun+))

Twin Cities Lisp Group Inaugural Meeting

Tue, 2009-06-09 18:00 - 20:00
Event type: 

Copied from Bill Clementson's blog for the historical value.

TWIN CITIES LISP GROUP INAUGURAL MEETING 9 June 2009, 6:00 PM - 8:00 PM CDT Common Roots Cafe Corner of 26th and Lyndale, Minneapolis, MN Temporary web page:

There's a lisp renaissance out there, spurred by the availability of several high-quality open source Common Lisp implementations (SBCL, CMUCL, Clozure CL, and CLISP, at least). After attending the 2009 International Lisp Conference in Cambridge ( I was fired up to see if we could share in some of this renaissance here in the Twin Cities.

I was also inspired by visiting with the Vancouver Lisp group, Lispvan. They meet roughly monthly at some location offering coffee, beer, and wine, where they have a talk and some mingling.

In the interests of setting up something like this here, I've (well, Josh Hamell did all the real work) set up a mailman mailing list, tc-lispers (, and I've reserved the meeting room at Common Roots Cafe (, which offers the aforementioned coffee, beer, and wine (and tasty food --- vegetarian is available and there seem to be at least some vegan options).

At the first meeting John Maraist will talk about the NST unit testing framework for Common Lisp, which he has been developing at SIFT (abstract follows). Then we can plan a next meeting, chat, mingle, and swap stories. Share and learn the latest Lisp applications, techniques, packages, and implementations. Show off your lambda tattoos, evil hacks, and wigflip graphics.

Please come if you can and, whether you can or not, please sign up for the tc-lispers mailing list.

Robert Goldman


NST: A Unit Test Framework for Common Lisp

In this talk we will introduce the Lisp unit test framework NST. SIFT developed NST for internal use on a number of ongoing Lisp projects, and we believe that the system is now mature enough to release more broadly. In this talk we will review the notion of a unit test, and introduce the use of NST in Lisp project development. NST's implementation makes interesting use of a number of Lisp features --- macro expansion, compile-time execution, metaobject protocols --- and we will discuss its current implementation as well as the lessons we learned along the way.

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