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Low Price Fags
by Sales Department 25 Sep '02

25 Sep '02

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Kanser tedavisi
by carctol＠yahoo.com 25 Sep '02

25 Sep '02

charset="US-ASCII"; charset="US-ASCII"; charset="US-ASCII"; charset="US-ASCII" Reply-To: carctol(a)yahoo.com Date: Thu, 26 Sep 2002 00:12:08 +0300 X-Priority: 3 X-Library: Indy 9.00.10 X-Mailer: Foxmail Kemoterapinin yan etkileri nedeniyle yorgun ve bitkin d�sm�s bir yakininiz mi var? Yanitiniz evetse vakit kaybetmeyin ve CARCTOL'u denemesini saglayin. Genelde ancak klasik tedavinin ise yaramadiginin anlasilmasi, insanlari baska se�enekler aramaya itmektedir, ancak o durumda maalesef yapacak fazla birsey kalmamaktadir. Ayni hatanin yapilmasina izin vermeyin ve hi�bir yan etkisi olmayan, Himalaya Dagi bitkilerinden �retilen Carctol'u denemesini saglayin. CARCTOL, birka� bin yillik, alternatif Hint Tibbinin (Ayuverda'nin) insanliga sundugu bir umut isigidir. �nceleri v�cudu takviye edici tonik olarak kullanilan bu �r�n simdi yeni form�l�yle kansere karsi etkili bir ila�tir L�tfen asagidaki siteye ugrayin ve Carctol'u yakindan taniyin. http://www.kanser-tedavisi.com esenlikler dileriz.. Listeden adinizin silinmesini istiyorsaniz a_cengiz2002(a)yahoo.com a bos e posta yollayin. Tesekk�rler

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layout problem
by Γιώργος Κοσμίδης 25 Sep '02

25 Sep '02

Thanks for your answer. The lines where as you asnwered me. When I post my mail the layout was tottally ruined. Here I post the program again but I have replaced all spaces with underscores ( _ ) This is the error that I have: ERROR "c:\textanalysis.HS":48 - Syntax error in declaration (unexpected `->') Thanks in advance for all the help that you can give me module Main where import IO import System import List import Maybe import Char import Numeric type Word=String type WordCount=Int type WordTup=(word,wordCount) type WordList=[WordTup] main=do args<-getArgs ________textLines<-getText ________switchArgs args textLines ________where ________switchArgs args textLines ________________________|(isMemberOf "-f" args) && (isMemberOf "-i" args) _________________________=printFreq(sortWordCount(parseLcLine textLines)) ________________________|(isMemberOf "-f" args) _________________________=printFreq(sortWordCount (parseLine textLines)) ________________________|(isMemberOf "-i" args) _________________________=printFreq(sortWordCount (parseLcLine textLines)) ________________________|otherwise _________________________=printFreq(sortName (parseLine textLines)) ________getText::IO String ________getText=do c<-getChar ___________________e<-isEOF ___________________if (e) _______________________then return "" else _______________________(do nc<-getText ___________________________return (:nc)) ________parseLine::String->Wordlist ________parseLine line __________________|(line/="")&&(isWantedChar (headline)) ___________________=fillWordList w(parseLine newLine) __________________|(line/="")&&(not(isWantedChar (headline))) ___________________=parseLine(tail line) ________isMemberOf::String->[String]->Bool ________isMemberOf arg args ___________________=[]/=[a|a<-args,a==arg] ________printFreq::WordList->IO() ________printFreq wl=do sequence (map putWordStat wl) ________________________where ________________________putWordStat(Word,WordCount)->IO() ________________________putWordStat(w,wc) ________________________do putStr w ___________________________putSpc (20 (length w) (length(show wc))) ___________________________putStr (show wc) ___________________________putSpc 8 ___________________________putStr (showFFloat (Just 2) (fromIntegral (wc) * 100.0/fromIntegral (wLength))"") ___________________________putChar '%' ___________________________putChar '\n' ________________________return() ________________________wlLength-countWords wl; ________putSpc::Int->IO() ________putSpc n _______________|n>1 do putChar '' _______________________putSpc (n-1) ________________return() _______________|otherwise=putChar '' ________countWords:Wordlist->Int ________countWords [ ] ________countWords ((w,wc):wl)=wc+countWords wl ________sortName::WordList->WordList ________sortName [ ] = [ ] ________sortName (wn:ws)=sortName [(w,wc) (w,wc) <-ws,not (isGreater (w,wc)wc)] __________________++[wn]++sortName[(w,wc)|(w,wc)<-ws, isGreater (w,wc) wn] __________________where __________________isGreater (wl,wcl) (w2,wc2) _____________________________|ord(head(wl))-ord(head(x2))>0=True _____________________________|ord(head(wl))-ord(head(x2))<0=False _____________________________|length wl>l && length w2>l ______________________________=isGreater(tail(wl),wcl) (tail(w2,wc2) _____________________________|otherwise = [] _____________________________where _____________________________w=parseWord line _____________________________newline=drop (length w) line ________parseLcLine::String->WordList ________parseLcLine line ____________________|(line/="") && (isWantedChar (head line))=fillWordList w (parseLcLine newline) ____________________|(line/="") && (not (isWantedChar (head line)))=parseLcLine (tail line) ____________________|otherwise = [] ____________________where ____________________w=map toLower (parseWord line) ____________________newline=drop (lenfth w) line ________parseWord::Word->Word ________parseWord w __________________|(w/="") && (isWantedChar (head w))=(head w): parseWord (tail w)) __________________|otherwise = "" ________isWantedChar::Char->Bool ________isWantedChar c _____________________| (c=='a'|| c=='b'|| c=='c'|| c=='d'|| c=='e'|| c=='f' || c=='g'|| c=='h'|| c=='i'||__c=='j'|| c=='k'|| c=='l'|| c=='m'|| c=='n'|| c=='o'|| c=='p'|| c=='q'|| c=='r'|| c=='s'|| c=='t'|| c=='u'|| c=='v'|| c==' w'|| c=='x'|| c=='y'|| c=='z'||c=='A'|| c=='B'|| c=='C'|| c=='D'|| c=='E'|| c=='F'|| c=='G'|| c=='H'|| c=='I'||__c=='J'|| c=='K'|| c=='L'|| c=='M'|| c== 'N'|| c=='O'|| c=='P'|| c=='Q'|| c=='R'|| c=='S'|| c=='T'|| c=='U'|| c=='V' || c=='W'|| c=='X'|| c=='Y'|| c=='Z'|| = True) _____________________|otherwise = False _______fillWordList::Word->WordList->WordList _______fillWordList w wordlistl ____________________|cWord/= [] =cWord++[wordl,wordCountl)|(wordl,wordCountl<-wordListl,wordl/=w] ____________________|otherwise = (w,l):wordListl ____________________where ____________________cWord=[(wordl,(wordCountl-l)) | (wordl,wordCountl)<-wordListl,wordl==w] __________________________________________________|length w1>1 && length w2==1=True __________________________________________________|otherwise = False ________sortWordCount::WordList->WordList ________sortWordCount [] = [] ________sortWordCount ((wn,wcn):ws=sortWordCount [(w,wc|cw,wc)<-ws,ws<=wvn++ _______________________[(wn,wcn)]++sortWordCount [(cw,wc)|(w,wc)<-ws,wcs,wcn]

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Monad Maybe?
by Russell O'Connor 24 Sep '02

24 Sep '02

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 [To: haskell-cafe(a)haskell.org] Is there a nicer way of writing the following sort of code? case (number g) of Just n -> Just (show n) Nothing -> case (fraction g) of Just n -> Just (show n) Nothing -> case (nimber g) of Just n -> Just ("*"++(show n)) Nothing -> Nothing - -- Russell O'Connor roconnor(a)math.berkeley.edu <http://www.math.berkeley.edu/~roconnor/> ``Any time you skip a commercial [...] you're actually stealing the programming'' -- Jamie Kellner, CEO of TBS -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (SunOS) Comment: For info see http://www.gnupg.org iD8DBQE9jM7juZUa0PWVyWQRAjmlAJ9+YDXUEXEhLTtb2huBZKskJ9JvegCgjPb2 iGb/vYYLK7I+UdfijtEePyQ= =6UZh -----END PGP SIGNATURE-----

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RE: Monad Maybe?
by Simon Marlow 24 Sep '02

24 Sep '02

> I know this has been written about way too much, but I was > wondering what > people thought about using 'liftM f' as opposed to '>>= > return . f'. I > would probably have written Andrew's code using liftM, but I > don't know if > one is necessarily better than the other. Does anyone have strong > thoughts on this? so, using liftM: (number g >>= return . show) becomes (liftM show (number g)) or (show `liftM` number g) but it's important not to get too carried away with abstractions - this example requires a bit of a trawl around the library documentation for someone not familiar with liftM. Personally, unless I was writing fragments like this a lot, I'd just write it as (do r <- number g; return (show r)) Each to his own I suppose. Cheers, Simon

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Re: Problems with IO
by ?????? ????? ????? ?????? 24 Sep '02

24 Sep '02

Now I understand that it's just a lack of knowledge... Sorry for interrupring... By the way, can you recommend a good manual which I can find on the web? -- Zhbanov Pavel

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Problems with IO
by Жбанов Павел Геннад ьевич 24 Sep '02

24 Sep '02

I'm having a problem with writing a function dealing with I/O. Maybe it's just a lack of experience or simple Haskell knowledge because I'm just a beginer. The problem: I want to write a function that converts an IO String into String lala :: IO String -> String Is it possible? If yes, how? -- Жбанов Павел

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question regarding ordering of function definitions
by David Roundy 23 Sep '02

23 Sep '02

Hello all! I've just started learning (and using haskell), and am also using the literate comment mode (latex style), and just ran into a problem that seems like it ought to have a simple solution, which is that it seems that haskell requires you to define all the variations of a function sequentially, which is raining on my literate programming parade. Here is what I'd like to do: \begin{code} data D = A String | B String instance Show D where show = showD instance Read D where readsPrec _ = readsD readD s = (readsA s) ++ (readsB s) \end{code} A is formatted like ``A string''. \begin{code} showD (A s) = "A " ++ s readsA s = [(A thestr, r) | ("A", x) <- mylex s, (thestr, r) <- mylex x] \end{code} B is formatted like ``B string''. \begin{code} showD (B s) = "B " ++ s readsB s = [(B thestr, r) | ("B", x) <- mylex s, (thestr, r) <- mylex x] \end{code} The problem I have is that ghc complains because I've split up the definition of showD with readsA defined in between. This surprised me, since it seemed that the code should still be unambiguous. Is there some nice way around this, or do I have to define a separate function for each constructor, and then have a list in one place (as I do with the readsD, in that case because pattern matching won't give me what I want), like: showD (A s) = showA (A s) showD (B s) = showB (B s) Of course, in my actual example, there are more than two constructors, and the parsing is considerably more complex, which is why I'd like to put the analagous showing and parsing right next to eachother along with a description of what the formatting is intended to be. -- David Roundy http://civet.berkeley.edu/droundy/

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"zipping" two streams in the IO monad
by Nick Name 19 Sep '02

19 Sep '02

How could I "zip" two possibily infinite streams obtained by IO operations, for example to return the infinite list of pairs of values read both from channel a and from channel b with getChanContents? In general, how does one implement a function like "getChanContents" wich returns an infinite list? Tell me just some pointer to information of course, I don't want an entire functional programming lesson :) Vincenzo

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Depth-First search problems
by Dennis Schieferdecker 19 Sep '02

19 Sep '02

Hi! I hope you can help me with this little problem I have: I'm trying to implement a depth-first search on a binary tree from a school book but somehow I always get Haskell error messages (more after the source code). The source is as follows: -- Binary Tree structure data BinTree t = EmptyTree | Bin (BinTree t) t (BinTree t) left (Bin b1 _ _) = b1 right (Bin _ _ b2) = b2 value (Bin _ v _) = v empty EmptyTree = True empty (Bin _ _ _) = False -- Give the Binary Tree == instance Eq a => Eq (BinTree a) where (Bin b v c) == (Bin d w e) = (v == w) && (b == d) && (c == e) EmptyTree == EmptyTree = True EmptyTree == Bin _ _ _ = False -- Stack structure data Keller t = CreateStack | Push (Keller t) t top (Push s x) = x pop (Push s x) = s -- Depth-First search tiefensuche b = fst (until p f ([], Push CreateStack b)) where p(_, k) = empty k f(erg, k) | (top k) == EmptyTree = (erg, pop k) | otherwise = ([v] ++ erg, Push( Push( pop k) b2) b1) where (Bin b1 v b2) = top k The error message says that p has a wrong types Haskell thinks it is p :: (b, BinTree c) -> Bool, instead of p :: ([a], Keller (BinTree a)) -> Bool I really don't know how I can tell to see the right type. Does anyone have an idea what I have to change ? -- ciao dennis "I hear and I forget, I see and I remember, I do and I understand"

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