Mailman 3 February 2004 - pypy-dev

Multimethods again
by Armin Rigo 07 Mar '04

07 Mar '04

Hello everybody, I just found out a neat way to do simple multimethods in Python, so I thought I'd share it with you :-) The following is only for dispatching over two arguments. The idea is to use a pair(a,b) object that is just like a tuple (a,b), but with methods. Any (regular Python) method that you put in the class of pair(a,b) works like a multimethod dispatching on both a and b. The metaclass hack is only a syntactic convenience. I don't know if this is relevant to PyPy. It's probably one of the shortest multimethod implementations for Python, whereas PyPy's is probably one of the longest :-) Armin # ______________________________________________ class extendabletype(type): """A type with a syntax trick: 'class __extend__(t)' actually extends the definition of 't' instead of creating a new subclass.""" def __new__(cls, name, bases, dict): if name == '__extend__': return bases[0] # return existing base else: return type.__new__(cls, name, bases, dict) def __init__(self, name, bases, dict): if name == '__extend__': for key, value in dict.items(): setattr(self, key, value) def pair(a, b): """Return a pair object.""" tp = typeofpair(a.__class__, b.__class__) return tp((a, b)) # tp is a subclass of tuple pairtypecache = {} def typeofpair(cls1, cls2): """type(pair(a,b)) is typeofpair(a.__class__, b.__class__).""" try: pair = pairtypecache[cls1, cls2] except KeyError: name = 'typeofpair(%s, %s)' % (cls1.__name__, cls2.__name__) bases1 = [typeofpair(base1, cls2) for base1 in cls1.__bases__] bases2 = [typeofpair(cls1, base2) for base2 in cls2.__bases__] bases = tuple(bases1 + bases2) or (tuple,) # 'tuple': ultimate base pair = pairtypecache[cls1, cls2] = extendabletype(name, bases, {}) return pair # ____________________________________________________________ class A(object): pass class B(object): pass class C(A): pass class D(B): pass a = A() b = B() c = C() d = D() assert isinstance(pair(a,b), typeofpair(A, B)) class __extend__(typeofpair(A, B)): def add((a, b)): print "a+b" def sub((a, b)): print "a-b" class __extend__(typeofpair(C, B)): def add((c, b)): print "c+b" # alternate less magic syntax def sub((a, d)): print "a-d" typeofpair(A, D).sub = sub pair(a,b).add() pair(a,b).sub() pair(c,d).add() pair(c,d).sub()

3 3

Re: [pypy-dev] sounds like fun.
by Laura Creighton 29 Feb '04

29 Feb '04

In a message of Sun, 29 Feb 2004 11:48:48 +0100, holger krekel writes: >[Laura Creighton Sat, Feb 28, 2004 at 12:47:50PM +0100] >> http://www.flashmobcomputing.org > >just need to grab a plane :-) More seriously, i wonder if >they couldn't do it over the internet ... > >Another interesting question what this has to do with >PyPy (or did i miss anything?) :-) > >cheers, > > holger Well, I was vaguely thinking -- aha, so _that's_ the sort of operating system we need to make, to handle these sorts of crazy people -- and, indeed, why not over the internet? (For these people, of course, it is 'so we can get media attention'). People are at least trying to think about networking in different ways :-) Be nice if we gave them a language they didn't have to count the bits in to develop some of these ideas. But that all sort of just passed through my mind in a nice rosy feeling, and then I posted here... sorry about that... Laura

1 0

sounds like fun.
by Laura Creighton 29 Feb '04

29 Feb '04

http://www.flashmobcomputing.org

2 1

Sprint on Stackless Python March 10-14 in Berlin
by Christian Tismer 27 Feb '04

27 Feb '04

As already announced, the *********************************************** *** *** *** S t a c k l e s s S p r i n t *** *** *** *********************************************** has now a settled date: It will take place in Berlin, March 10-14 2004. We will have a room in the Free University of Berlin in Berlin-Dahlem. Address and room will be announced, soon. How to attend? See bottom of this message. Contents? Well, there is a lot possible. Current topics which come into mind are * autoscheduling * scheduling object * brain storming! * Zope Wiki and Documentation * making channels really stackless * demo applications * more regression tests * real zope apps? * refactoring Stackless: simpler and configurable * create a Stackless tutorial * minimalist Stackless Python with no hardware dependency * assembly-free Stackless with setjmp/longjmp * spreading the internals between developers but this is completely open for discussion. Level? Well, it will be a bit simpler than the pypy-sprints, which I think are very difficult, but Stackless has its built-in difficulties by nature. Usability? This is by far, now and forever, the best possible way to learn about Stackless Python and to become a core developer. But no guarantee possible :-) Payback? Well, it is intended that Stackless Python should be developed further. If you are using or planning to use Stackless for your products, you are highly encouraged to support Stackless Python by money and by submitting your best developers, regardless how painfully they are going to be missed by the company. Coaching? Yes, it is probable and whished, that Stackless Python will become a topic for training and coaching. First of all, we will try to leverage our knowledge. Fun? Guaranteed. Schedule -------- There is no particular schedule, yet, but for the first day. I am planning to give a talk on Stackless technology, and to be available for questions and discussion during the whole first day. Attendees with small or no knowledge about Stackless Python are strongly encouraged to join that session. Accomodation ------------ There are no special arrangements planned. We hope to find a place for every external sprinter at the home of the Berlin habitants. I'm taking two already, please don't ask. How to attend: -------------- Please subscribe to the mailing list stackless-sprint(a)stackless.com which you can find via this interface: http://www.stackless.com/mailman/listinfo/stackless-sprint By subscribing, you state that you want to come to the sprint. We have only limited reources left and can take only a few. ------- I hereby wish to thank *Dirk Pape* and *Christoph v. Stuckrad* from FU Berlin for making this event possible! cheers - chris -- Christian Tismer :^) <mailto:tismer@stackless.com> Mission Impossible 5oftware : Have a break! Take a ride on Python's Johannes-Niemeyer-Weg 9a : *Starship* http://starship.python.net/ 14109 Berlin : PGP key -> http://wwwkeys.pgp.net/ work +49 30 89 09 53 34 home +49 30 802 86 56 mobile +49 173 24 18 776 PGP 0x57F3BF04 9064 F4E1 D754 C2FF 1619 305B C09C 5A3B 57F3 BF04 whom do you want to sponsor today? http://www.stackless.com/

1 0

Trac, a wiki/tracker system using subversion
by Nicolas Chauvat 26 Feb '04

26 Feb '04

Hi, I have not tried it, but thought this might be of interest since I read here discussions about developping such a tool, IIRC. It's GPL and written in Python. ----- Forwarded message from Daniel Lundin <daniel(a)edgewall.com> ----- Trac 0.5.1 Release Notes ======================== Feb 25, 2004 Edgewall Software is pleased to announce the release of Trac 0.5.1. Trac is a minimalistic web-based software project management and bug/issue tracking system. It provides an interface to Subversion, an integrated Wiki and convenient report facilities. Trac allows wiki markup in issue descriptions and commit messages, to create links and seamless references between bugs, tasks, changesets, files and wiki pages. A timeline shows all project events in order, making getting an overview of the project and tracking progress very easy. The software is published under the GNU General Public License, and is available for download at: <http://projects.edgewall.com/trac/download/> Please report problems and provide feedback using the issue tracker at: <http://projects.edgewall.com/trac/> For questions, comments and discussions, please use the Trac mailing list - list info, subscription and archive available at: <http://lists.edgewall.com/mailman/listinfo/trac/> For more information, please visit the main Trac web site: <http://trac.edgewall.com/> -- Daniel Lundin | Edgewall Software daniel(a)edgewall.com | Professional GNU/Linux & Open Source Consulting http://www.edgewall.com/ ----- End forwarded message ----- -- Nicolas Chauvat logilab.fr - services en informatique avancée et gestion de connaissances

1 0

Looks like a place for the 'interpreted languages need not be slow' talk
by Laura Creighton 20 Feb '04

20 Feb '04

http://www.sebastian-bergmann.de/InterpretedLanguages2004/ This workshop is part of the Net.ObjectDays, a conference on OO- and Internet-based technologies: http://www.netobjectdays.org/node04/en/index.html Should we give a paper? Laura

2 1

Pycon preliminary talk schedule out.
by Laura Creighton 15 Feb '04

15 Feb '04

I will skip a bit ... I have devised a schedule that would accommodate all the talks in two parallel sessions. I hope it's at least a starting point for discussion. The schedule assumes the following daily schedule. Daily schedule - -------------- Keynote 9:00 - 10:00 Break 10:00 - 10:30 Session 10:30 - 12:00 Lunch 12:00 - 1:00 Session 1:00 - 3:00 Break 3:00 - 3:30 Session 3:30 - 5:00 <snip> I gave ids to the session -- ex. Session 1.2b. The first number is the day (1, 2, 3), the second number is the session within the day (1, 2, 3), the letter a or b distinguishes between parallel tracks. Jeremy <snip> Session 1.2a (4) - --------------- IronPython: a fresh look at Python on .Net Jim Hugunin Faster than C: Static Type Inference with Starkiller Michael Salib Pypy - implementing Python in Python Jacob Hallén >From Python to PLT Scheme Daniel Silva Session 1.2b (4) - ---------------- Python in Chemical and Bioinformatics Andrew Dalke A Finite Volume PDE Solver Using Python Daniel Wheeler and Jon Guyer Data Extraction and Analysis Program Amy L. Shelton Modeling of a Fuel Fabrication Facility Using Python and SimPy J.D. Doak <snip> So it looks as if we are to give a technical talk in with a bunch of other technical talks about New Pythons, opposite Scientific Apps using Python. Laura

2 1

Sprint on Stackless Python!
by Christian Tismer 12 Feb '04

12 Feb '04

*********************************************** *** *** *** S t a c k l e s s S p r i n t *** *** *** *********************************************** Dear Stackless Friends and Python developers, we are planning a sprint on developing and learning Stackless Python. It will be located in Berlin, happening probably somewhere in March 2004. Duration is not settled, maybe little more than a weekend, maybe more, this depends on what you like. Contents? Well, there is a lot possible. Current topics which come into mind are * autoscheduling * scheduling object * brain storming! * Zope Wiki and Documentation * making channels really stackless * find the Bajo bug if I still can't? * demo applications * more regression tests * real zope apps? * minimalist Stackless Python with no hardware dependency * assembly-free Stackless with setjmp/longjmp * spreading the internals between developers but this is completely open for discussion. Level? Well, it will be a bit simpler than the pypy-sprints, which I think are very difficult, but Stackless has its built-in difficulties by nature. Usability? This is by far, now and forever, the best possible way to learn about Stackless Python and to become a core developer. But no guarantee possible :-) Fun? Guaranteed. Please contact me. cheers - chris -- Christian Tismer :^) <mailto:tismer@stackless.com> Mission Impossible 5oftware : Have a break! Take a ride on Python's Johannes-Niemeyer-Weg 9a : *Starship* http://starship.python.net/ 14109 Berlin : PGP key -> http://wwwkeys.pgp.net/ work +49 30 89 09 53 34 home +49 30 802 86 56 mobile +49 173 24 18 776 PGP 0x57F3BF04 9064 F4E1 D754 C2FF 1619 305B C09C 5A3B 57F3 BF04 whom do you want to sponsor today? http://www.stackless.com/

1 0

neat academic paper on software prototyping and productivity.
by Laura Creighton 10 Feb '04

10 Feb '04

http://citeseer.nj.nec.com/hudak94haskell.html Executive Summary: take a jr programmer who has never seen Haskell before. Give him 8 days with the online manual. Then tell him you get to make a Geometric Region Server for the US Nacy Naval Surface Warfare Center (NSWC). When he was done, surprise, surprise, the evaluators thought that the code he submitted was only pseudo-code, requirements. No. Working Haskell. His version was faster and done more quickly than other versions, written in more standard languages like Ada and C++. VHLL rock. Laura

2 1

danger on codespeak / password change neccessary!
by holger krekel 10 Feb '04

10 Feb '04

hello users of codespeak, we today discovered that the account 'nico' on codespeak.net has been compromised probably due to a bad password. Before i go into some details please *change your password* immediately. Besides users of codespeak.net this also affects all non-anonymous users of cvs.infrae.com (still an alias for codespeak.net). Every non-changed password will be reset to some random password automatically after 2 days (on 6th of february). We currently think that the attacker was not able to gain more than user access and was not able to modify other than the user's files. If we find evidence of a more severe breakin than just abuse of one user account we may switch off the server without further notice. As the attacker effectively got to some encrypted information in /etc/shadow (see later how) he may now be able to crack any naive password in the next days. So please change your password - or even better - also install SSH-RSA Keys so you don't need to have a nice'n easy password. Here are some more details about our current findings. - the attacker installed new ssh-RSA keys and changed the password of the compromised account - he went through a lot of configuration files in /etc and tried to change them (unsuccessfully as far as we see it). - he then went on to install and run some password cracker and IRC-net utilities (at least 'psybnc-2.3.1-8' and 'john-1.6') and ran them. - the attacker obviously didn't like 'vi' because he tried to find other editors like 'pico' which were unfortunately not installed :-) - he actually run the password cracker app for around 217 minutes accumulated time (when we killed it off). - he was able to create a password file which resembled encrypted information from /etc/shadow which is normally not accessible by users. Now the question is how he did the attacker get to this information which he didn't have direct access rights to? The probable answer (juding from the web server's logfiles) is that he was able to gain acess to a subversion-checkin of /etc/shadow at http://codespeak.net/svn/sysconf/thoth.codespeak.net/etc/shadow While everything under /svn/sysconf/ is not accessible anonymously *viewcvs* bypasses access control as it doesn't use the apache-layer but directly works with the repository on the file system layer. Apparently he found that by googling for it. Thus he was able to get to the encrypted information on which he then started 'john', the password cracker. Our countermeasures so far included: - disabling of login/ssh/public_html access for nico - killing two user-processes (one for IRC proxy-bots and one for password cracking) - generically preventing any URL with something like 'sysconf/thoth.codespeak.net' in it in order to not leak sensible system information - continued analysis of traces, logfiles and system binaries which could be used to hide traces. (actually the modern way of hiding traces is to install a kernel module which hides itself from 'lsmod' and additionally hides processes and directories following specific patterns. But it doesn't seem like the attacker was able to do this especially because he didn't know how to handle vi :-) However, as we must assume that the /etc/shadow encrypted information is now out there we it's an important safety measure probably a good idea that everybody changes his/her password unless you are sure that you have a very good password (like the ones we usually generate for new users). If you don't know your password anymore or if you want a good random one just sent me an mail. Please don't look around the codespeak system (e.g. into /etc) in the next days when you login but just change your password. Otherwise we may assume that another account is about to be cracked ... or if you really want to look around (you are welcome) then mail us before you start. sorry for the inconvenience, holger

6 6