LISP & Scheme User Community

Tips for hosting in Europe?

2008-07-09T01:39:52Z

Does anybody here have any experience with hosting SBCL on real or virtual servers in Europe?

I've discovered the hard way that Xen is the only virtual server system that plays well with SBCL. Budget Dedicated have been doing a reasonable job with Xen so far, but the website's responsiveness just ain't there. I'm getting the itch to move to dedicated hardware (just as everybody's going the other way); anybody have any tips?

I refuse to use USA-based hosting, because "adult" content is involved, and I don't need politically-motivated trouble from there, any more than I need it from here in Australia. At worst, I'll hire a server here until/unless I get actual problems, but I really don't need to scramble in response to a take-down notice.

So... any tips? A quick initial search has turned up EasySpeedy, which looks promising.

[Edit: FlexiScale also looks good. Might just test their offering and report back.]

Flamewar? What flamewar?

2008-02-15T04:55:28Z

Everybody agrees, at least in principle, that the right tool should be used for the job. It just so happens that for many people, their favourite tool is the right one for all jobs.

An old saying about only having a hammer comes to mind.

Given Lisp's famously protean ability to be adapted to the job at hand, even if command-line scripting is a bit awkward, I offer the following answer to Perl's nickname:

Lisp - the Swiss-Army hammer of programming languages!

Warning: tongue may need surgical extraction from cheek after use

pop langs website ranking

2008-02-11T00:55:53Z

while doing my website's traffic report, i did some research on major computer lang or tech website ranking. Here's the result ranked by alexa.com (some non-lang tech sites are given just for comparison):

Php.net             550  (largely due to online doc and forum)
sun.com             900  (java doc and forum)
java.com           1122
slashdot.com       1223  (forum)
Mysql.com          1296  (online doc, forum)
gnu.org            7328  (massive docs, mailing list archives)
wolfram.com        9065  (online doc, mathworld etc)
Python.org         9410  (python doc and prob forums)
Perl.org          26067  (perl doc, forum)
paulgraham.com    48153  (lisp bigwig, but huh?)
Perl.com          49104
haskell.org      118703
novig.com        130568  (lisp bigwig)
franz.com        292598
lispworks.com    377906   (common lisp doc)
Gigamonkeys.com  529551   (pop common lisp book)
schemers.org     880284

The list is not that surprising.

Many top ones are due to the popularity of the lang, but also because their site hosts the lang's documentation and discussion forum (or wiki,blogs). Hosting a web forum are likely to increase traffic some 10 or 100 fold.

Questions:

• paulgraham.com is unusually high. What's up with that?

• python.org at 9k seems also unusally high, compare that perl.org with online doc and forum is only 26k. Python.org has mailing list archives... maybe blogs too but am not sure it has forums... still the gab seems surprising. Even perl is not much talked about these days, but i'm guessing its market share is at least still 10 or 100 times of python...

If any one so wishes, add entries to the above list.

lisp @ 2008-02-07T04:11:00

2008-02-07T12:12:11Z

just discovered today:

http://en.wikipedia.org/wiki/NewLisp

http://newlisp.org/

http://newlisp.org/index.cgi?page=Features

Returning nothing explicitly

2008-02-02T16:45:50Z

It seems that in R5RS scheme it is possible to write a function that, in some circumstances, does not return anything. A short example:

(define foo
 (lambda args
  (if (null? args) 'mumble)))

will return nothing if passed at least one argument.

Is there a built-in way of doing this explicitly? Something like:

(define arc-if
 (lambda args
  (cond
   ((null? args) #nothing)
   ((= (length args) 1) (car args))
   ((car args) (cadr args))
   (else (apply arc-if (cddr args))))))

EDIT: On further research, it seems the appropriate mechanism is (values).

Arc is out

2008-01-30T19:09:17Z

Paul Graham's new language, inspired by Lisp. Read more here..

some lisp logos

2007-12-24T05:20:16Z

A few lisp logos:

LISP Logo
http://xahlee.org/emacs/lisp_logo.html

Qi Language Logo
http://xahlee.org/emacs/qi_logo.html

and on tangent recently wrote:
The Purpose of Logos and Principles of Logo Design
http://xahlee.org/UnixResource_dir/logo_design.html

the strengths of the academic enterprise

2007-12-24T05:16:22Z

The strengths of the academic enterprise

Xah Lee, 2007-12

The following is some notes after reading one of the essay from a influential computer scientist, and is posted to comp.lang.scheme in 2007 Dec.

Recently, i ran into a essay by by Edsger W Dijkstra, titled “The strengths of the academic enterprise”. (1994)

I think it is fitting in particular of the recent r6rs fiasco.

HTML version here:
http://xahlee.org/Periodic_dosage_dir/industry_and_university.html

The full essay is here: http://www.cs.utexas.edu/users/EWD/transcriptions/EWD11xx/EWD1175.html

Below are some excerpts:

...

My third remark introduces you to the Buxton Index ... The Buxton Index of an entity, i.e. person or organization, is defined as the length of the period, measured in years, over which the entity makes its plans. For the little grocery shop around the corner it is about 1/2,for the true Christian it is infinity, and for most other entities it is in between: about 4 for the average politician who aims at his re-election, slightly more for most industries, but much less for the managers who have to write quarterly reports. The Buxton Index is an important concept because close co-operation between entities with very different Buxton Indices invariably fails and leads to moral complaints about the partner. The party with the smaller Buxton Index is accused of being superficial and short-sighted, while the party with the larger Buxton Index is accused of neglect of duty, of backing out of its responsibility, of freewheeling, etc.. In addition, each party accuses the other one of being stupid. The great advantage of the Buxton Index is that, as a simple numerical notion, it is morally neutral and lifts the difference above the plane of moral concerns. The Buxton Index is important to bear in mind when considering academic/industrial co-operation.

... Just for being different and doing things the uneducated cannot understand, the academics are hated and feared, vide Socrates, executed in 399 BC, Archimedes, killed in 212 BC, and, more recently, Hypatia, AD 415 barbarously murdered by a Christian mob. The original Oxford Colleges were buildings fortified in order to protect the students against the rabble, and if you think that that is old hat, I refer you to the DDR or the People's Republic of China of only 25 years ago. It is a miracle whenever, these days, the academic world is tolerated at all; personally I am convinced that what tolerance there is would completely disappear, were the academic world to become secretive.

President Reagan did not seem to see it that way, but even regimes of modest insight seem to understand that, as a corrective measure, the gadfly's sting is indispensable. The university has therefore the task to nurture the authority of the sting, both for its own protection and as a service to mankind. Aforementioned openness and honesty, though essential, are not enough; we should add a ruthless striving for perfection, ruthless in the sense that, on campus, there is no academically valid excuse for compromises.

The sting also defines the social responsibility of the universities. The question is: do we offer what society asks for, or do we offer what society needs? If the two coincide, there is no problem, but often they don't, and in computing such coincidence is extremely rare. In case of discrepancy, you must ignore what they ask for and give what they need, ignore what they would like and tell them what they don't want to hear but need to know. There are two compelling reasons for this uncompromising position.

...

... what society overwhelmingly asks for is snake oil. Of course, the snake oil has the most impressive names —otherwise you would be selling nothing— like “Structured Analysis and Design”, “Software Engineering”, “Maturity Models”, “Management Information Systems”, “Integrated Project Support Environments” “Object Orientation” and “Business Process Re-engineering” (the latter three being known as IPSE, OO and BPR, respectively). The external pressures to do the wrong thing are enormous, but yielding to them would be fatal for the academic enterprise, while resisting the pressure reinforces its strengths. The pressures are, in fact, so strong that I do not know a university where there is not some faculty or some department that has yielded, but there should be no mercy for snake oil pedlars on campus. [When a professor is no better than James Martin, he should start a business instead.]

...

Xah's Note: The republic of China mentioned above refers to the Cultural Revolution (a political strugle started by Mao Zedong, where students persecuted and killed professors and professionals. (wikip states half a million killed)).

For film depictions, see:

* Farewell My Concubine (film)↗
* To Live↗

Socrates (one of the greatest philosopher of antiquity) is ordered to be killed politically because he refused to bulk his teachings.

Wikip quote: 「Socrates was tried and convicted by the courts of democratic Athens on a charge of corrupting the youth and disbelieving in the ancestral gods.」

Archimedes is the greatest mathematician of antiquity, and one of or possibly the one greatest mathematician of all times. He was killed by a soldier.

Hypatia is one of the great matheamtician, and the very first female mathematician. She was murdured by Christians. (draged naked to death) (i named one of my servers in dotcome time as Hypatia, and have naked pict of her here: Hypathia & Lady Godiva )

Convenient wikip links:

* Cultural Revolution↗
* Socrates↗
* Archimedes↗
* Hypatia↗

Over all i liked this essay. However, it seems a bit of a unfocused and ranty and not very cogent for me. For example, he indicates the importance of universities by first citing it is “... 66 institutions have enjoyed a continuously visible identity since 1530”. This seems quaint to me. He didn't explain exactly what source or report this is based on. (e.g. does that include Asia?)

His main point about how Academicians shouldn't yield to outside pressures, overall i think is very good idea. However, the way he expressed it does not seems very concrete to me. For example, he has mentioned in the article that universities function as a sting to society, but in later parts of the essay, the way he expressed how business shouldn't work with universities, seems to entail the opposite danger where academecians become a bunch of effete group doing no fundamental research and have no idea what goverments and business in real world is like, but cloistered in his ivory tower playing with their own cocks.

I think Edsger prob doesn't want this, but the way he expressed his ideas in his later parts of the essay kinda entangle it.

In general, i think here are some main issues:

* (1) should universities yield to current status and trends from politics and business.
* (2) should, or could, universities work with corporations/governments?
* (3) the concept that universities is a cloistered entity.

I think most parties would agree that (1) is bad. That is, i think both academicians and perhaps most industrial/goverment people would largely agree that academy's researchs should not be dictated or influenced much by current needs and trends. But more for the pure research, fundamental questions, or long-term goals.

As for (2), Edsger's clearly indicates no. Personally, i'm not sure about that. He used the “Buxton Index” to show incompatibilities. (“buxton index”?! what a quait idea) Other than this, he doesn't give much reasons. Whether schools and business can coorporate fruitfully depends on many things and aspects such as what is meant by coorporation, and what defines success... surely corporations can give school the much needed money and school can produce immediate useful results sometimes and this has happened a lot. Of course such short-term gain may be a long-term damage... but in general his assertion that schools and business should not work together isn't convincing to me.

For (3), the concept is not well defined... it could bring different pictures to different people. For example, he pictured it such that schools should be aloof in their pursuit of perfection in pure research, thus schools should not yield or work with businesses. However, from another perspective, academics can be sometimes or often (as happened in history) become corrupt and effete that they enclose themselves doing dead reseach or day-dreaming and have little to no effect on their society or students. (personally, i perceive many (US) academecians to be like this... throwing grand jargon amongst and pleasure themselves and understand little of what or how real is functioning and having no impact on society)

... above are some of my thoughts on reading Edsger's essay. I don't think this essay of his is very good, but anyway the above's the rant of my own. His essay is of interest to schemers because schemers face the same question of the relationships of Industry and University about Scheme the lang, in particular the recent R6RS controversy.

(am not really in Scheme community, but i think R6RS is not good and Scheme implementators should unite politically to oppose it. (by, for example, refuse to implement it, or implement just the part you think is good.) One particular thing about the R6RS i've read is that the voting system used is a any-Joe system. i.e. any moron, can vote, by just having sufficient intelligence to write a letter expressing their fandom, to be onboard. And, seems to me those 1/3 who opposed R6RS are mostly older, more experienced Schemers or implementators ... (no, don't quote me ..., because i haven't verified much of my claims))

Developer-friendly Hosting?

2007-12-22T22:41:31Z

Hello Friends

I am interested in exploring web programming via Lisp, Ruby on Rails, and several of the popular Python frameworks.

Here are the features I am interested in:

* Lisp hosting including access to web servers and/or mod_lisp
* Ruby on Rails hosting
* Python hosting
* Configurable source control repository with public and private areas (SVN/Trac or better)
* SSH access
* MySQL or PostgreSQL database
* PHP support (for third-party software packages)

Has anyone here had similar needs? Would you recommend any particular hosting solution?

Thanks,
jkndrkn

Tips For Editing Lisp Code With Emacs

2007-12-19T14:55:32Z

Tips For Editing Lisp Code With Emacs

Xah Lee, 2007-12

This page gives you some tips about editing emacs lisp code in emacs. Most tips will also apply to editing other lisp language codes or code with many nested matching pairs. (This page is presumes emacs version 22, release in 2007.)

http://xahlee.org/emacs/emacs_editing_lisp.html

wow

2007-11-30T18:56:52Z

is it me or are exercises in computer programming books designed to torture you?

damn sicp or k+r exercises are killers esp for a beginning programmer......jesus!

I am a mental ping pong ball

2007-11-17T01:11:10Z

I tried learning common lisp using Paul Graham's ANSI common lisp.
pain
I tried practical common lisp +slime+emacs.
pain
I tried perl+vi
dull ache as operator precendence, hashes, arrays, and others built up many fun things to remember.

Now I am wondering what is wrong.

Why is programming so hard for me to learn?

Am I underestimating the time invoved to learn howto program?

lisp @ 2007-11-16T01:18:00

2007-11-16T08:18:22Z

dlweinrebfeed: Dan Weinreb was one of the engineers who worked on the original lispm systems!

sandbox

2007-11-03T16:26:12Z

hi, i'd like to evaluate lisp code in a sandbox
so it can't access the file system and things like that

are there ways to do this?

Text Processing with Emacs Lisp

2007-10-29T23:57:35Z

Text Processing with Emacs Lisp
Xah Lee, 2007-10-29

This page gives a outline of how to use emacs lisp to do text
processing, using a specific real-world problem as example. If you
don't know elisp, first take a gander at Emacs Lisp Basics.

THE PROBLEM

Summary

I want to write a elisp program, that process a list of given files.
Each file is a HTML file. For each file, i want to remove the link to
itself, in its page navigation bar. More specifically, each file have
a page navigation bar in this format:

...

HTML version with links and colors is at:
http://xahlee.org/emacs/elisp_text_processing.html

how to stop livejournal from interpreting angle brackets as html tags?

Elisp Lesson: Image file path linkify

2007-10-24T18:38:18Z

Elisp Lesson: Image file path linkify

Xah Lee, 2007-10-24

This article shows a example of writing a emacs lisp function that creates a customized HTML inline image link.

--------------------------------
The Problem

Summary

I want to write a command, so that, when invoked, emacs will turn the current line into a HTML inline image link, with width and height attributes and a alt text based on the file name. (the current line being a image file's path)

This lesson will also show you how to call shell commands and process their results.

Detail

A HTML version of this essay with colors and links is at:
http://xahlee.org/emacs/elisp_image_tag.html

inserting a point into an ordered list

2007-10-23T02:38:40Z

So, I'm working in emacs and I need to write a procedure (make-sorted-pt-list p pt-list) that assumes the points in pt-list are in sorted order of increasing distance from the origin, and returns a sorted point list containing p and all the points in pt-list, with p inserted in the proper position to maintain the sorted order.

(define (make-sorted-pt-list p pt-list)
(cond ((null? pt-list)
p)
((< (distance p origin) (distance (get-first-point pt-list) origin))
(cons p (pt-list)))
(else (cons (get-first-point pt-list) (make-sorted-pt-list p (get-rest-points pt-list))))
)
)

Get-first-point is basically car and get-rest-points is cdr, and (distance p1 p2) produces the distance between two points.

But when I try to execute (display (make-sorted-pt-list (cons 5.5 5.5) test-sorted-list))
where test-sorted-list is ((1 . 1) (2 . 2) (3 . 3) (4 . 4) (5 . 5) (6 . 6)), I get the message
The object ((6.6)) is not applicable.
Any ideas?

Fucking parens...

Elisp Tutorial: HTML Syntax Coloring Code Block

2007-10-18T08:34:15Z

Elisp Tutorial: HTML Syntax Coloring Code Block

Summary

I want to write a elisp function, such that when invoked, the block of text the cursor is on, will have various HTML style tags wrapped around them. This is for the purpose of publishing programing language code in HTML on the web.

Detail
...

http://xahlee.org/emacs/elisp_htmlize.html

[SOLVED] asdf and "does not designate any package" message

2007-10-14T10:09:38Z

I download cl-json as tgz, unpack it and make in visible for asdf. As I can see, asdf is able to load it:

CL-USER> (asdf:oos 'asdf:load-op :cl-json)
; loading system definition from
; /usr/local/common-lisp/registry/cl-json.asd into #<PACKAGE "ASDF0">
; registering #<SYSTEM :CL-JSON {117CFD61}> as CL-JSON
; registering #<SYSTEM :CL-JSON.TEST {118E6651}> as CL-JSON.TEST
; loading system definition from
; /usr/local/common-lisp/registry/parenscript.asd into #<PACKAGE "ASDF0">
; registering #<SYSTEM :PARENSCRIPT {11A5B111}> as PARENSCRIPT
; registering #<SYSTEM :PARENSCRIPT.TEST {11BFA4A9}> as PARENSCRIPT.TEST
...  some style warinigs here ...
; compilation unit finished
;   caught 5 STYLE-WARNING conditions
NIL

But when I try to use this package error appears:

; compiling file "/Users/rk/work/projects/jotter/trunk/rp-rpc/rp-rpc.lisp"
; compiling (DEFPACKAGE #:RP-RPC ...)
debugger invoked on a SIMPLE-ERROR:
  Error during processing of --eval option (LOAD #P"server.lisp"):

  The name "CL-JSON" does not designate any package.

rp-rpc.lisp is:

(defpackage #:rp-rpc
  (:use #:cl-json
	#:rp-orm
	#:cl)
  (:export
   ping))

(in-package #:rp-rpc)

;;; constants
(defconstant +RPC-SERVER-VERSION+ "0.1 prealpha")

;;; functions definitions
(defun-json-rpc ping ()
  "Return verion of RPC server"
  +RPC-SERVER-VERSION+)

Can anybody explain what I doing wrong?

[SOLVED]: see xach comment.

A Simple Lisp Code Formatter

2007-10-12T22:58:05Z

A Simple Lisp Code Formatter

Xah Lee, 2007-10-12.

(this essay is a edited version originally posted to comp.emacs. It outlines a simple heuristic on a lisp code formatter)

Xah wrote: «As to lisp, it would be nice, if a programer can press a button in emacs, then the current code block would be formatted by a simple lexical analysis. (similar to how fill-paragraph would work) I think it is relatively trivial to code his command, but to my surprise, it is not done. I was told by one Scheme expert Taylor R Campbell (aka Riastradh, author of paren-edit mode) that this is non-trivial, but i couldn't believe it and maybe he misunderstood what i wanted about this command.»

http://xahlee.org/emacs/lisp_formatter.html

Multiuser server on SBCL with usocket

2007-10-06T10:53:24Z

I looking for any example of implementation of multiuser server on sbcl with using usocket package.

What do I want:
* server listen some address/port
* if client put in port some data, server should return amount of bytes in data
* server should be able to serve several clients simultaneously
* connection closing should be activated on client side

Now I have mockup for playing (its just REPL):

(require 'usocket)

(defconstant +address+ "127.0.0.1"
  "Listening address")

(defconstant +port+ 9300
  "Listening port")

(defconstant +backlog+ 2
  "Queue length")

(defun start-rp-listener () 
  "Start the server."
  (let ((sock (socket-listen +address+ +port+ 
			     :backlog +backlog+ :reuseaddress t)))
    (let ((cstream (socket-stream (socket-accept sock))))
      (loop for line = (read-line cstream nil)
	 while line do (progn (format cstream "~A~%" (eval (read-from-string line)))
			      (force-output cstream)))
      (close cstream))))

(start-rp-listener)

In general it works, but:
* only one client can use server
* connection does not closes at all :) ever I close it on client side by "quit" command (I use telnet for testing)

Can anybody help? :) Just a few keywords can help me :) I able to read docs and source code, but I dont know which one I should read :)

PS: if my english is not clear for you, feel free to ask explanation :)

common lisp app server webserver

2007-09-29T17:34:21Z

I saw hutchentoot on cliki. Do all lisp web servers work with apache? Do any of them work standalone? I would love to power a website with common lisp like Paul Graham did..

grrrrr

2007-07-19T17:13:25Z

Alright, this is absolutely asinine.

I pulled down LispBox so I wouldn't have to bother trying to figure out all the bizarre things I'd need to set up to get a working REPL. Up to now it has worked well, except for the completely insane key combinations somebody decided to use. However, I absolutely cannot get it to load stuff I've downloaded. I pulled down a package with some .asd files, which some research has shown me are files related to ASDF, a system I have little to no knowledge of, and one that apparently was created by a team who was summarily shot so that the secret of using the system would never be revealed to the outside world. I found out that I could instruct SLIME to automagically search for .asd files with a line like this in site-init.lisp:

(register-source-directory (lispbox-file (make-pathname :device "C" :directory '(:absolute "lispbox-0.7"))))

However, if I then do:

(require 'asdf)
(require 'cl-some-package)

I get a big screaming error about it not finding "cl-some-package.lisp". I put the package into \packages\some-package, and there is a .asd file, as well as a bunch of .lisp files

This is making me absolutely crazy. What am I doing wrong, and what bearded psychopath thought that he'd created a wonderful editor?

DC

say what?

2007-07-12T17:49:30Z

Okay, so I've got a little project going to get into Lisp, and it's going pretty well. However, I've run into a deficiency that I refuse to believe exists. Here we go.

The project is basically an emulator for a mythical machine called TINY that we used in college to learn assembly programming. It's got a really small instruction set, and that part is pretty much all done. The part that's causing me trouble is getting input from a file. Well, that's a little misleading. I can get stuff out of the file, but I'm having trouble figuring out how to turn a string like "123" into the number 123. I'm convinced I must have missed something somewhere. This has to be in Common Lisp. What am I missing?

DC

a beginner's quandary

2007-07-06T20:33:58Z

So I'm going back to learn LISP again. It's been something like six years since I last had any contact, which basically means I'm starting from scratch. I found the online version of Paul Graham's On Lisp, I've read several FAQs and watched a few videos, and I feel like I've got a pretty good hold on the language, at least from a syntactic angle. It's not particularly complicated in that regard, as I'm sure you're all aware.

My problem, however, is that I can't really learn a language just by reading about it. I suspect that's not independent of the programmer community at large. The real issue is that I've spent my entire professional career, as well as the vast majority of my educational and personal programming time, working with and building object oriented systems with stuff like C, C#, and (to a lesser extent) Java. It's really hard to draw a line between that kind of modularity and the kind of modularity that seems to be within Lisp's purview. Maybe I just don't have a good mental grasp on it, though.

It feels like a complete logical disconnect in terms of breaking down a problem mentally. What are some good, simple projects a Lisp novice could attempt to try and get his mind into the right gear for functional programming to look more like a viable programming technique and less like an academic masturbatory aid?

DC