toronto-lisp October 2010

toronto-lisp@common-lisp.net

12 participants
14 discussions

[toronto-lisp] Land of Lisp
by Brian Connoy 28 Oct '10

28 Oct '10

Conrad Barski's "Land of Lisp" is available now in eBook form (hardcopy soon to follow)! http://landoflisp.com/ I see in the acknowledgements the name "Christopher Brown". Perchance, is that our own Toronto-Lisp "Christopher Browne" !? BC

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[toronto-lisp] Lambda question
by Aleksandar Matijaca 19 Oct '10

19 Oct '10

Hi there, a quick question - I have a reasonably firm understanding of how lambda functions work, however, I cannot immediately see why you would want to use one, when you can write a perfectly good NAMED function instead... So under which circumstances would you absolutely want to use a lambda function and why, and under which circumstances would you absolutely NOT want to use a lambda function.. Thanks, Alex.

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[toronto-lisp] Mandelbrot set renderer, in memory of Benoit Mandelbrot
by Vish Singh 18 Oct '10

18 Oct '10

I wrote a quick Mandelbrot set renderer in Clojure, after hearing the sad news that the great mathematician Benoit Mandelbrot passed away this weekend. Watch his TED talk (http://www.ted.com/talks/benoit_mandelbrot_fractals_the_art_of_roughness.ht…) and you will find it hard to feel as if you didn't know him. It was simple and fun to write, as Clojure has support for complex numbers. It took me a while to figure out how to turn that support on, though. It takes less than a minute to run, and can surely be optimized. http://github.com/vishsingh/mandelbrot The output of the program looks like this: http://github.com/vishsingh/mandelbrot/raw/master/result.png It can surely be extended quite easily to zoom in to smaller parts of the set. Vish

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[toronto-lisp] Announcing SocialTechCampToronto Saturday Oct 23rd
by Ushnish Sengupta 17 Oct '10

17 Oct '10

Apologies for any duplicate postings, but would love to have some projects from Toronto Lisp Users Group presented. Event: SocialTechCampToronto Date: Saturday Oct 23rd Time: 9:00 am to 5:00 pm Location:OISE (Ontario Institute for Studies in Education) Building 252 Bloor Street West 7th Floor Toronto, Ontario M5S 1V6 (on top of St. George subway station) Format: Presentations 9 am-12:30 pm, Breakout groups 1:30 pm to 5:00 pm The Breakout groups will be formed in a BarCamp style "unconference" where the topics are determined by the people present. Description: There are a number of Social Technology projects underway in the Greater Toronto Area as well as a number of individuals who are working on international Social Technology projects. All of these projects have an Open Source component. In conjunction with Open Source Week Toronto, we will hold an event which will enable dialogue and collaboration between projects and individuals. For the unconference, we welcome any proposals on the following topics and related topics: 1) Providing computers to nonprofits 2) Setting up computer centres in low income apartment complexes 3) Providing Linux Ubuntu desktops and training to individuals 4) Public access hot spots in public spaces such as parks 5) Free wireless networks 6) International projects such as the World Computer Exchange, and One Laptop Per Child. 7) Design for people with disabilities Add your topics at: http://barcamp.org/w/page/SocialTechCampToronto Please register at: http://stcu.freegeektoronto.org/ This is a free event!

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[toronto-lisp] Scheme interpreter for iPhone
by Aleksandar Matijaca 17 Oct '10

17 Oct '10

I installed it and tried it. Great little thing just for testing small code snippets. Taken by a_matijaca http://www.flickr.com/photos/26563081@N00/5087485415 Sent from my iPhone

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[toronto-lisp] quicklisp
by Paul Tarvydas 16 Oct '10

16 Oct '10

FYI, as posted by Zach Beane: I recently released a beta version of my Quicklisp project. Quicklisp is a library manager for Common Lisp. It can download, install, and load any of over 300 libraries with a few simple commands. Quicklisp is easy to install and works with ABCL, Allegro CL, Clozure CL, CLISP, CMUCL, ECL, LispWorks, SBCL, and Scieneer CL, on Linux, Mac OS X, and Windows. For more info, see: http://quicklisp.org/beta/ Please give it a try and let me know what you think. Thanks, Zach

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[toronto-lisp] Found a development technique that works for me
by Aleksandar Matijaca 14 Oct '10

14 Oct '10

For LispWorks, instead of typing my code in repl, I type it in the editor, also compile there , and use repl for testing only. I have noticed that the editor has some very handy buffers and definitions menus. Exactly the stuff I was looking for. Sent from my iPhone

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[toronto-lisp] embedding Jython
by Aleksandar Matijaca 09 Oct '10

09 Oct '10

At our last meeting, I mentioned my use of python as a utility to make a Java application "programmable". There seemed to be some interest in this technique. I used this technique in a web app I built for one of my clients. They needed to change formulas for calculating aluminium window frame sizes without having me involved. Sometime the calculating formula would change by 0.25 of an inch… So, here is a technique where python interpreter is embedded in Java code, the Java then for the sake of this demo, sets a object in Python called X - does a little bit of manipulation of it on the Python interpreter, and then, sets a variable of the executing class SimpleEmbedded via "this" - and then execute a callback from Python back into Java… This very cool feature alone, makes the Jython interpreter very versatile (and potentially dangerous)… PyObject shown below is the most primitive Object that can be easily cast if need be into other objects… Python also does have an eval() function which can lead to other very interesting and convoluted possibilities... References: *http://www.jython.org/* <http://www.jython.org/> Embedding Python in Lisp (maybe somebody really well versed in lisp can try it??) *http://common-lisp.net/project/python-on-lisp/*<http://common-lisp.net/project/python-on-lisp/> ============================================== Sample running code… ============================== File: SimpleEmbedded.java import org.python.util.PythonInterpreter; import org.python.core.*; public class SimpleEmbedded { // this method below will be called back by the Python interpreter public void nasty(Object PyObject) { System.out.println(" python sez - "+PyObject); } public SimpleEmbedded() { PythonInterpreter interp = new PythonInterpreter(); interp.exec("import sys"); interp.exec("print sys"); interp.set("a", new PyInteger(42)); interp.exec("print a"); interp.exec("x = 2+2"); PyObject x = interp.get("x"); System.out.println("x: "+x); interp.set("myjavaclass", this); //YEAH BABY... very cool here.. set Python object myjavaclass the "address" of this object - a callback of sorts interp.execfile("c:/test.py"); } public static void main(String []args) throws PyException { SimpleEmbedded se = new SimpleEmbedded(); } } ============================== Test.py ### Variable x has been set by the Java program to the inerpreter.. ## just a little simple math for the sake of the demo num = x*4 ## Calling BACK the Java method nasty -- the ability to do this gives ## us the ability to build very very complex 5gen type very high level ## utilities that analysts and other non-programmers can use.. myjavaclass.nasty(num) ============================== Output on console... below <module 'sys' (built-in)> 42 x: 4 python sez - 16 ============================================================== I did not want to include this code into the git-hub at this point, and if you think it's of itnerest, I will put it into the git-hub... Regards, Alex.

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[toronto-lisp] October meeting minutes
by Vish Singh 09 Oct '10

09 Oct '10

attendees: Paul Tarvydas Vish Singh Aleksandar Matijaca Leo Zovic Doug Hoyte discussion topics: - Doug talked about the state machine compiler he's using (I think it was http://www.complang.org/ragel/) - compiles to C code - he uses it to build state machines for parsing HTTP streams - Let Over Lambda did something similar, with finding a substring within a chunked stream - easy to make mistakes in such code, so better to use a DSL - does Clojure make full use of all CPU cores? I think so, but there was some debate here. - some discussion on JIT compilation - Alex described how shared-memory concurrency can be implemented using in-memory databases - Antiweb uses Berkeley DB in a similar way - Y2K problem, fixing it using automated tools - more programming war stories (fascinating for me, definitely helps in appreciating modern technology) - discussion of articles: "Crash-Only Software" and "A Benchmark for Multi-Core Machines" - using Clojure within Java projects - obstacles to the use of Lisp professionally in Toronto? - jaded attitudes towards the language due to many people's experiences with early Lisps (interpreted, slow) - fixation on the idea that it's an AI language, even though nowadays you can do just about anything with it - (my own attitude: Lisp needs better branding.. Clojure is helping us in that respect) - Land of Lisp book, game programming

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[toronto-lisp] Fwd: Development helpers
by Aleksandar Matijaca 09 Oct '10

09 Oct '10

Hi there, first of all Paul and Dave, thanks for replying!! The question can perhaps be best explained with an example: repl=> (defun doit-3 (x) (* 3 x)) repl=> '(some more cool stuff) repl=>'(and more and more) i keep testing and playing around with functions more and more I can certainly run my doit-3 function repl=>(doit-3 4) 12 repl=> and now, I say to myself, - how the heck did I write that doit-3, I forgot, because, I wrote it 20 minutes ago, it obviously exists inside REPL because I can execute it... So, how do I view [dump??] the contents of doit-3 to the screen, or to a file on the disk, so I can invoke an editor and modify doit-3 and then reload it?? I am just interested in learning how to be more productive in a standard software development cycle. Thanks, Alex. On Wed, Oct 6, 2010 at 4:59 PM, Paul Tarvydas < tarvydas(a)visualframeworksinc.com> wrote: > > Hi there, > > > > A bit of a noob question - let's say that I have an interactive Repl > > session that has been going on for about an hour or so, and all of a > > sudden I wish to modify a defun I wrote a while ago. What is the > > easiest way first to show that code on the console, modify it, and > > load it back into Repl ? > > > > I am just trying to come up with a comfortable development environment > > for myself. > > There is something called "(dribble)" which records a transcript of your > session. I've never used it. > > With LW, I typically use the editor to type into a file (buffer) and > compile-load the buffer, or ^E one form or defun. Undo can get you back to > an earlier state. I find that if I'm experimenting, I do it a function at a > time, until I'm happy with it, so I never have to go back a full hour. > > I take it that most free lisp users use emacs+slime. You split the emacs > window into two, one half shows your edit buffer, the other shows a lisp > interaction. A keystroke sends your current form to the interaction and you > see the result in the interaction buffer. > > pt > > _______________________________________________ > toronto-lisp mailing list > toronto-lisp(a)common-lisp.net > http://common-lisp.net/cgi-bin/mailman/listinfo/toronto-lisp >

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toronto-lisp October 2010