Novembre 2007 - Gambit-list - mailman.iro.umontreal.ca

Edge triggered I/O with libevent
by Adam Langley 05 Avr '13

05 Avr '13

Gambit uses the select call on POSIX systems to multiplex IO operations. This is fine for small numbers of file descriptors, but falls apart quickly with large numbers[1]. libevent[2] is a wrapper library around a number of modern IO multiplexing systems (epoll on Linux, kqueue on the BSDs as well as poll and select). Attached is a patch which converts Gambit to using edge triggered I/O with epoll and libevent. This also requires a patch (attached) of libevent since the standard distribution doesn't include edge triggering support and the upstream appears to be on holiday. (epoll is required because I don't have a BSD box on which to develop edge triggering support for kqueue) This patch (for Gambit) preprocesses away to nothing unless --enable-libevent is passed to the configure script. (Note that, since this patches the configure.ac script, you'll need to run autoconf to regenerate). I hope I've not broken anything, but at this stage I've only tested that the console and tcp ports work. This patch (in the future) should also allow people, who write programs which use socket calls directly, to integrate into the main event loop at some point. Testing is more than welcome and, if you find a form of IO which is broken, please email me. [1] http://monkey.org/~provos/libevent/libevent-benchmark2.jpg [2] http://monkey.org/~provos/libevent/ -- Adam Langley agl(a)imperialviolet.org http://www.imperialviolet.org (+44) (0)7906 332512 PGP: 9113 256A CC0F 71A6 4C84 5087 CDA5 52DF 2CB6 3D60

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Please don't delete the .c file
by Bradley Lucier 07 Fév '08

07 Fév '08

Marc: I needed to debug a gsc-compiled file with gdb today, and it was fairly inconvenient that the .c file wasn't left around by compile- file in beta 21. I suggest that the .c file be left around for the various source tools that need it. Brad

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Wraith Scheme 1.30 released (for Macintosh); does parallel processing - comp.lang.scheme | Google Groups
by Bradley Lucier 30 Nov '07

30 Nov '07

I haven't tried this yet, but it looks somewhat interesting. Brad http://groups.google.com/group/comp.lang.scheme/browse_thread/thread/ aeb19e5dc9bcdc46#c86cce5b5598971a

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Dates
by Guillaume Cartier 27 Nov '07

27 Nov '07

Does anyone know of Scheme code or library to manipulate dates a bit like the Java Date and Calendar classes. E.g. stuff like : - format a date: 2007/11/03 05:10:23 - add units to a date like (date-add date 3 'day) -> date + 3 days - convert between times (seconds since the epoch) and dates - ... Thanks, Guillaume

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Easy Console Input
by Rouan van Dalen 22 Nov '07

22 Nov '07

Hi everyone. I was wondering what the easiest way in Gambit is to read a string from the console. The idea is to prompt the user for a message and let him type in a string response. Thanks. ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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web framework requirements
by Maarten Koopmans 20 Nov '07

20 Nov '07

Hi, I haven't done any heavy lifting in Schme but have written a lot software in Rebol, a proprietary languag e that (at least to me) is in the same family. Just to be sure: the family thing is not what I want to discuss. I have written quite a few web applications and like Scheme, had to built most of it from the ground up. I doing so I noticed that the framework isn't important; the "intrinsic" power of the language is, provided that there are some common libraries. The most powerful languages seem (in general) Rebol, Lisp, Scheme. But again that's not my point. Provided you'd want to write web applications you need the following functionality at least: - a dynamic include (module) system - a templating engine (e.g. the <% %> tags in html edited pages) - A FastCGI interface with all CGI processing capabilities one would expect (FastCGI is pretty good supported the last two years; it took some time but finally it is something you can actually use) - Basic encryption to protect consumer data: RSA, DH and AES as well as SHA1 or better - database interfaces to mysql and optionally postgresql - some XML (de-)serialization mechanism, though I personally try to avoid XML whenever possible Then your average webapp is just a FastCGI process with a database connection that can process templated pages or other CGI requests (hello REST) smartly and generate secure sessions. If the language that runs all this is symbolic the data manipulation part becomes easier and that's where the real gain will be. Now the question is: if you look at the above list, what's there and what's not? I'd be willing put some time in the remaining (to b written) components for Gambit-C. And if possible even in a portable way. Just my 2 eurocents.... --Maarten

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Thanks and Thoughts For "Scheme on Skis" :)
by Rouan van Dalen 20 Nov '07

20 Nov '07

Hi everyone. Thank you for the quick and earnest responses. It is great to be involved with such great people. There are a lot of communities out there that laugh at newbies and give really bad responses to beginner-questions. The Gambit community is a great one to be in. Here I will try to provide a quick introduction of myself :) I am currently living in South Africa and I am 24. I have been developing software for about 7 years and it is what I love to do. I have been actively developing in the following technologies: o) C/C++ o) Ruby/Rails o) PHP o) C# / APS.NET I am currently busy working for a company doing a huge C# / ASP.NET project. However this is not really what I want to do. I have recently discovered Common Lisp and the ideas and mechanisms really opened my eyes. I then read a lot about CL and eventually wondered into Scheme. I started writing some simple pieces of code in CL and was surprised: I loved it. I am a bit of a performance freak so I started looking around at many different LISP implementations, trying to find one that is well-supported, has a great community, is fast, and can be used to write commercial or enterprise applications. This road eventually led to Gambit (of course :) ). So I found a love for CL and Scheme and I like Scheme just a bit more because it's very clean. So i started downloading and buying books on Scheme, including: o) the little schemer o) the seasoned schemer o) LiSP in Small Pieces (quite a heavy read for me :)) Ok, now I have been developing Rich Internet application for a while now and love writing web applications. Then I thought it would be great if I can write web applications using Scheme :) Most of my knowledge is self-taught because I love to read. There are no good CS courses here that cover Scheme / CL in great detail, so I am a bit green in this area. Ok, so that intro was a bit longer than expected :) Everything boils down to this basically: I love writing software in Scheme and would like to build big projects with the help of other, smarter individuals, learn a ton of new stuff and have fun in the process. I have been looking for an open source project to contribute to and I believe I have settled on Gambit. I want to move Scheme out of the academic light and into the "you can write serious business applications" light. So I am going to need a lot of help and input from the Gambit community :) (but I don't think that will be a problem). I might not have all the experience or expertise for such a project, but I make up for it with enthusiasm and love of programming in Scheme :) Ok so on to the scheme community's new web framework : "Scheme on Skis" (thanks Marc). I will be actively involved in this project and will be spending my time gathering ideas from all you smart people :) I am currently setting up a website and will keep everyone posted. I would really like this project to be a community effort, so I am always open and listening to new ideas, comments, criticism, etc. The goal is to build a stable web framework (using Gambit) that is blazingly fast, easy to use, and has good support for current web standards. I have elected myself not as the leader of this project, but simply an organizer. Any objections are welcome :) . Anyone that has a component or is working on a component related to web applications are welcome to contact me. I welcome the use of already-developed modules that can simply be used in the web framework. We also need to decide on branding for our Scheme on Skis, creating a slogan, logo, graphics etc. Any ideas are welcome. There is a ton of stuff to do before we get started, but the most difficult part of any project is to get started. So this is an official start for Scheme on Skis :) I will be heavily relying on Marc and other individuals with lots of experience and I would like to thank everyone in advance. Rouan. ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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[ANN] Gambit-C v4.1.0 released
by gambit＠iro.umontreal.ca 14 Nov '07

14 Nov '07

Gambit-C v4.1.0 is now available. Changelog: http://www.iro.umontreal.ca/~gambit/repo/gambit/?shortlog The sources and prebuilt distributions can be obtained from the Gambit web site by visiting one of the following links. sources: http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/source/gambc-v4_1_… prebuilt: http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/prebuilt/gambc-v4_… http://www.iro.umontreal.ca/~gambit/download/gambit/v4.1/prebuilt/gambc-v4_…

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Web Framework
by Rouan van Dalen 14 Nov '07

14 Nov '07

Hi everyone. Thanks again for all the replies. David, would you mind sharing your code so we can have a look at it. I will be primarily concerned with writing code on Linux, not Windows, so the idea is to get it working on Linux first and then on Windows. Both platforms will be supported. Its just that Linux has priority for any platform-specific (non-portable) code. I would like to know what Linux distros are used by everyone else. This is just something interesting. I am using Zenwalk and Arch Linux. I am familiar with OOP because most of the languages I use regularly support OOP. I would like to do things the Scheme way for the web framework. Are there any suggestions as to what paradigm the framework should support by default. I don't have any particular attachments to OOP. I believe in the right tool for the right job. But I am interested in doing everything the Scheme way, so if there is a better way to do something in Scheme, I will do it that way :) . I have also had a look at Meroon (an object system for Scheme ;) ). I like the MVC pattern because it is suited especially for web development. This is the pattern that I had in mind for the web framework. Any ideas in this are are also much appreciated. I have also had a look at HOP. It is very interesting and I think I can learn a lot from them and have a look at how they do things. They seem to be on the track that we are on (or the other way around :) ). But it seems that porting the code might be an issue as the code is very Bigloo-specific. I think we can use their ideas, but we are going to do our own implementation. As far as javascript libraries go, I have been working with Scriptaculous and Prototype for a while now. Prototype is very straight-forward to work with. This is also the same javascript libraries used by Rails. Any suggestions here are much appreciated. The web framework should make it easy for anyone to hook-in their own javascript library of choice. On the name of the web framework, I do like the name "Scheme on Skis", but I have to agree with Guillaume. We should try to keep things original. So any suggestions on naming our web framework are welcome. However, I do like the word-play in Scheme on Skis. I will be creating a document describing the decisions that are made regarding the web framework. I will post this on the website which I will be finishing in the next week or so. I use OpenOffice for all my documentation. On a totally different note, how can I read user input from the console in Gambit. I am using *read-line* to read the input, but I need a function that blocks and waits until the user enters some text. I then need the entire input text as a string to work with it. Thank you so much for everyone's quick responses and interest in this project. Rouan ___________________________________________________________ Yahoo! Answers - Got a question? Someone out there knows the answer. Try it now. http://uk.answers.yahoo.com/

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OOPSLA 2007 « Dan Weinreb’s Weblog
by Bradley Lucier 12 Nov '07

12 Nov '07

For those who couldn't make it to Montreal recently, here's an interesting review of the recent confluence of the Dynamics Languages Conference, the Montreal Scheme Lisp User Group Meeting, and OOPSLA. I've highlighted a few things I want to keep around in one of my mail folders. http://dlweinreb.wordpress.com/2007/10/28/3/ > Brooks highly recommends the book “Peopleware” (I have a copy but > haven’t read it yet; clearly I should.) > Kathy Sierra talked about how to create passionate users; that is, > how to make products that will get users excited and enthusiastic. > This was completely fascinating and I took two whole pages of > notes. She has given this talk before, and there is commentary on > the web about it already; see: > > http://conferences.oreillynet.com/cs/os2005/view/e_sess/7077 > > http://www.oreillynet.com/onlamp/blog/2005/08/ > tutorial_review_creating_passi.html > > And a blog at: > > http://headrush.typepad.com/creating_passionate_users/ > > She’ll also be writing a book about it soon, to be published by > O’Reilley. > Sebastian Fleisner from Hong Kong talked about Epi-Aspects: Aspect- > Oriented Conscientious Software. By “conscientous” he means “self- > sustaining”, continuing to work in the face of failure. This is > based on a paper last year by Richard Gabriel and Ron Goldman about > “Conscientious Software”. Its abstract is: “Software needs to grow > up and become responsible for itself and its own future by > participating in its own installation and customization, > maintaining its own health, and adapting itself to new > circumstances, new users, and new uses. To create such software > will require us to change some of our underlying assumptions about > how we write programs. A promising approach seems to be to separate > software that does the work (allopoietic) from software that keeps > the system alive (autopoietic).” The presentation talked about the > latter part as having operations like monitor, test, repair, and > kill. Their proposal has to do with using aspect-oriented > programming to achieve this. What they’re talking about sounds a > lot like some of what I’m currently doing in my own work on Hot > Upgrade, and I intend to read both papers and see if there are any > good ideas I can use.

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