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Lisp on xkcd.com, very funny!
by Magnus Therning 16 Feb '07

16 Feb '07

I think the readers of this list will appreciate this http://xkcd.com/comics/lisp.jpg /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus(a)therning.org Jabber: magnus.therning(a)gmail.com http://therning.org/magnus Software is not manufactured, it is something you write and publish. Keep Europe free from software patents, we do not want censorship by patent law on written works. What if I don't want to obey the laws? Do they throw me in jail with the other bad monads? -- Daveman

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Summer of code and spam
by Magnus Therning 16 Feb '07

16 Feb '07

There seems to be a serious problem with spam on Haskell's SoC page: http://tinyurl.com/fl2dw Or maybe that's a general problem for hackage? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus(a)therning.org Jabber: magnus.therning(a)gmail.com http://therning.org/magnus

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Unicode Strings and ICU for Haskell
by Brian Smith 16 Feb '07

16 Feb '07

Has anybody written a wrapper for ICU (International Components for Unicode) for Haskell (GHC and/or Hugs)? I am processing Thai text and I want to use the ICU word-breaking, collation, encoding conversion, and transliteration services from my Parsec-based parsers. Also, what is the plan for Unicode string processing for Haskell? What is the standard module for high-performance, Unicode-capable strings? Thanks, Brian [1] http://icu.sourceforge.net/ [2] http://www-306.ibm.com/software/globalization/icu/index.jsp

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Summer of Code
by Bryan Burgers 16 Feb '07

16 Feb '07

Hello, Yes, I realize it's mid-February right now and the summer is still months away, but it's probably not too early to think about the future. I am wondering if there are any Summer of Code projects that I would be able to do for the Haskell community. I will be graduating from my undergrad program this semester and am hoping to go on to graduate school in the fall, and I think a good Haskell project would be the perfect way to spend my transitional summer. I looked at http://hackage.haskell.org/trac/summer-of-code/query?status=new&status=assi… to see if there was anything that people already had in mind, but that page looks old and unkempt (judging by the abundance of advertisements) so I am not sure which of those are still available or needed. So, are there any projects that will need a student for the summer? If this is not the place to ask, where should I be asking? Bryan Burgers

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Programming an Evaluation Context
by Klaus Ostermann 15 Feb '07

15 Feb '07

Hi there, in structural operational semantics, an evaluation context is often used to decompose an expression into a redex and its context. In a formal semantics on paper, an expression can just be "pattern matched" over the grammar of an evaluation context. If one wants to implement such a semantics in the form of an interpreter, I could not come up with a similarly nice solution. I have declared two separate data types (one for expressions, and one for evaluation contexts) and explicit functions to convert an expression into a (evaluation context, redex) pair. For example, I could have data Expr = Val Int | Plus Expr Expr and data Ctx = Hole | CPlusl Ctx Expr | CPlusr Int Expr Are there any tricks to mimick more closely what is going on in the formal semantics? Klaus

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Where can I find XmlRpc package?
by keepbal 15 Feb '07

15 Feb '07

http://www.cs.chalmers.se/~bringert/darcs/blob/Makefile BlobXmlRpc: GHCFLAGS += -package XmlRpc I can't find XmlRpc,so I use haxr instead,but it doesn't work.

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factorising to prime numbers
by Dougal Stanton 15 Feb '07

15 Feb '07

Hi folks, I recently read in my copy of Concrete Mathematics the relationship between prime factors powers and lcm/gcd functions. So I decided to reimplement gcd and lcm the long way, for no other reason than because I could. If you look at the definition of 'powers' you'll note it's infinite. So there's no easy way to take the product of this list, if I don't know how many items to take from it. Is there a better way to turn an integer N and a list of primes [p1,p2,p3,...] into powers [c1,c2,c3,...] such that N = product [p1^c1, p2^c2, p3^c3, ...] If I'm missing something really obvious I'll be very grateful. I can't really work out what kind of structure it should be. A map? fold? D. -- Concrete Mathematics -- Graham, Knuth & Patashnuk module Concrete where import Data.List -- the sieve of eratosthenes is a fairly simple way -- to create a list of prime numbers primes = let primes' (n:ns) = n : primes' (filter (\v -> v `mod` n /= 0) ns) in primes' [2..] -- how many of the prime p are in the unique factorisation -- of the integer n? f 0 _ = 0 f n p | n `mod` p == 0 = 1 + f (n `div` p) p | otherwise = 0 powers n = map (f n) primes --gcd :: Integer -> Integer -> Integer --gcd = f . map (uncurry min) -- Dougal Stanton

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Data.ByteString.Lazy.Char8 and finding substrings
by Magnus Therning 15 Feb '07

15 Feb '07

I'm curious, why doesn't Data.ByteString.Lazy.Char8 have the functions for searching for substrings that Data.ByteString.Char8 has (isPrefixOf, isSuffixOf, isSubstringOf, findSubstring and findSubstrings)? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus(a)therning.org Jabber: magnus.therning(a)gmail.com http://therning.org/magnus

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Calendar Dates before the epoch
by jim burton 14 Feb '07

14 Feb '07

It seems that CalendarTime is for dates since the epoch...what do I use to handle dates before that? Sorry if this is an FAQ, I looked on the wiki and tried to find MissingH since I thought it might be in there, but don't know where to find it. I also found this from 2003 - http://www.arcknowledge.com/gmane.comp.lang.haskell.libraries/2003-11/msg00… - is the code in a library somewhere? Thanks. -- View this message in context: http://www.nabble.com/Calendar-Dates-before-the-epoch-tf3221685.html#a89477… Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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Network.CGI.Compat.pwrapper
by Gracjan Polak 14 Feb '07

14 Feb '07

Hi, I wanted to setup really simple http server, found Network.CGI.Compat.pwrapper and decided it suits my needs. Code: module Main where import Network.CGI import Text.XHtml import Network doit vars = do return (body (toHtml (show vars))) main = withSocketsDo (pwrapper (PortNumber 7777) doit) Pointng any browser to http://127.0.0.1:7777 does not render the page. It seems the response headers are broken. How do I report this bug (trac? something else?). We might want to either fix it, or just get rid of it, as nobody seems to notice the problem :) $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.6 Tested under WinXP and MacOSX 10.4.9. Another question is: how do I do equivalent functionality without pwrapper? -- Gracjan

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