[Haskell-cafe] Trees (Rose Trees?)
hi I was curious as to whether my implementation of a Rose Tree and a sumTree function was correct. The aumTree adds up the elements of a tree. data Tree a = Leaf a | Node [Tree a] sumTree :: Tree Int - Int sumTree (Node []) = 0 sumTree (Node xs) = sum (map sumTree xs) The problem with this is I get a pattern matching error. Am I representing trees right... see below. Also, would an empty tree be represented by ... Node [] with this implementation? How would I represent a tree of the form... Tree (Node 2(Node 6 Empty Empty) Empty) taken from a binary one. Like this? Node [ [Leaf 2], Node [ Leaf 6,Node[],Node[] ], Node[] ] Ryan _ Find the best and worst places on the planet http://clk.atdmt.com/UKM/go/101719807/direct/01/___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] help
hi I am writing a basic Parser from scratch. So far I have functions;#
removeSpaces# match - which checks if a string is a substring of another#
orParser which combines two parser's abilities# Basic pasrers like... parseInt,
parseTrue, parseFalse, parseBoolusing the orParser on True and False.What I
want to do now is have a parseBinaryOp that recognises:parseBinaryOp + (5 +
2) if gives [(EInt 5, EInt 2, if)]So I
think that I have to split the initial string into four parts.+ becomes op'('
becomes tokenF')' becomes tokenB5 becomes e12 becomes e2parseBinaryOp ::
String - String - [(Expr, Expr, String)]parseBinaryOp op str = let
(tokenF,e1,op,e2,tokenB) =I am not sure how to go about separating the string
for how I need itusing my other functiuons. Ryan
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[Haskell-cafe] parsebinaryoperations
hi I have a function parseInt... which needs an error guard for when the input is not an Int. parseInt :: ParserparseInt [] = []parseInt xs = let (digits, rest) = span isDigit (removeSpace xs)in [(EInt (read digits), removeSpace rest)] Also... I have a function that does this... parseBinaryOp + (5 + 2) if gives...[(Int 5, Int 2, if)] so, op is '+' or . I am unsure of how to begin... parseBinaryOp :: String - String - [(Expr, Expr, String)]parseBinaryOp op str Thankyou Ryan _ Celeb spotting – Play CelebMashup and win cool prizes https://www.celebmashup.com___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] help
hi I have a function parseInt... which needs an error guard for when the input is not an Int. parseInt :: ParserparseInt [] = []parseInt xs = let (digits, rest) = span isDigit (removeSpace xs)in [(EInt (read digits), removeSpace rest)] Also... I have a function that does this... parseBinaryOp + (5 + 2) if gives...[(Int 5, Int 2, if)]so, op is '+' or . I am unsure of how to begin... parseBinaryOp :: String - String - [(Expr, Expr, String)]parseBinaryOp op str Thankyou Ryan _ Get free emoticon packs and customisation from Windows Live. http://www.pimpmylive.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] binaryop
hi sorry for vagueness. I am writing a basic Parser from scratch. So far I
have functions; # removeSpaces # match - which checks if a string is a
substring of another # orParser which combines two parser's abilities # Basic
pasrers like... parseInt, parseTrue, parseFalse, parseBoolusing the orParser on
True and False. What I want to do now is have a parseBinaryOp that recognises:
parseBinaryOp + (5 + 2) if gives
[(EInt 5, EInt 2, if)] So I think that I have to split the initial string
into four parts. + becomes op '(' becomes tokenF ')' becomes tokenB 5
becomes e1 2 becomes e2 parseBinaryOp :: String - String - [(Expr, Expr,
String)]parseBinaryOp op str = let (tokenF,e1,op,e2,tokenB) = I am not sure
how to go about separating the string for how I need itusing my other
functiuons. Ryan
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[Haskell-cafe] Need help please.
hi I am writing a basic Parser from scratch. So far I have functions;#
removeSpaces# match - which checks if a string is a substring of another#
orParser which combines two parser's abilities# Basic pasrers like... parseInt,
parseTrue, parseFalse, parseBoolusing the orParser on True and False.What I
want to do now is have a parseBinaryOp that recognises:parseBinaryOp + (5 +
2) if gives [(EInt 5, EInt 2, if)]So I
think that I have to split the initial string into four parts.+ becomes op'('
becomes tokenF')' becomes tokenB5 becomes e12 becomes e2parseBinaryOp ::
String - String - [(Expr, Expr, String)]parseBinaryOp op str = let
(tokenF,e1,op,e2,tokenB) =I am not sure how to go about separating the string
for how I need itusing my other functiuons. Ryan
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[Haskell-cafe] general
hi I have a problem. Function A is a function that passes its input into B Function B is a function that does something once. How do I make it so function A is done multiple times without adding a third function? Ryan _ Who's friends with who and co-starred in what? http://www.searchgamesbox.com/celebrityseparation.shtml___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] general-revised
hi I have four functions below: What I want to do is have a way to parse more than one digit or more than one string head in ParseTrue. Any ideas... removeSpace:: String - StringremoveSpace = dropWhile (`elem` space) where space = [' '] match :: String - String - (Bool, String)match word str| ((isPrefixOf) (removeSpace word) (removeSpace str)) = (True,rest) | otherwise = (False,str) where rest = drop (length (removeSpace word)) (removeSpace str) parseDigit :: String - [(Int, String)]parseDigit (x:xs) | isDigit x = [(read [x],xs)] | otherwise = [] parseTrue :: String - (Bool, String)parseTrue x = match True x Ryan _ Celeb spotting – Play CelebMashup and win cool prizes https://www.celebmashup.com___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] do... error
hi
test :: Parser (Char,Char) test = do x - item item
y - item return (x,y)
How come this brings an error saying that after do {} it must end with an
expression.
Ryan
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[Haskell-cafe] annoying output
hi
The code below does almost what I want but not quite! It outputs...parseInt
12444a gives...
[(EInt 1,2444a),(EInt 2,444a),(EInt 4,44a),(EInt 4,4a),(EInt 4,a)]
What I want is: [(EInt 12444, a)]
data Expr = EInt {vInt :: Int} -- integer values | EBool {vBool :: Bool} --
boolean values
parseInt :: Parser parseInt (x:xs) | (isDigit x xs /= []) = [(EInt (read
[x]),xs)] ++ parseInt xs | isDigit x xs == [] = [(EInt (read [x]),[])] |
otherwise = []
Thanks
Ryan
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[Haskell-cafe] parser
hi Can anyone advise me on how to check whether a string contains ints, chars, bools, etc 2345 + 6767 shoudl give IntAdd (2345) (6767) 2345 should give IntT 2345 Ryan _ Who's friends with who and co-starred in what? http://www.searchgamesbox.com/celebrityseparation.shtml___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] matching
hi I have a matching problem... I am wanting to identify whether or not a string is an opening substring of another (ignoring leading spaces). I have this: word is a single word and str is a string. match :: String - String - (Bool, String)match word str | if removeSpace str `elem` (removeSpace word) ++ rest = (True, rest) | otherwise == (False,str) where rest = str Any help? Ryan _ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] isSpace
hi I am having trouble with a function that is supposed to eliminate spaces from the start of a String and return the resulting string. I reckon a dropWhile could be used but the isSpace bit is causing me problems... words :: String - String words a = case dropWhile isSpace a of - s:ss - (s:word) : words rest where (word,rest) = break isSpace ss Thanks Ryan _ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] isSpace
HI I will try and explain it better. I am meaning to write a function that takes a string, apple and eliminates the spaces at the start ONLY. called removeSpace :: String - String I decided to use the function 'dropWhile' and another one 'isSpace' in the 'removeSpace' function. removeSpace:: String - String removeSpace a = case dropWhile isSpace a of - I get stuck here... I am not sure how to go about this function. Any ideas. Ryan _ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] missed clause???
hi I was testing my code when I came across a strange predicament. The input is a list of ints and a Results type which is of type [(int,...),(Int..)..]. I am comparing each int from the list to the first element in each member of results. But it works for 1-9 but not for 10 onwards why? Have I missed a clause anywhere.. it only does the first one after that. --Print the points of eight games poolsPoints :: [Int] - Results - Int poolsPoints [] [] = 0 poolsPoints [] _ = 0 poolsPoints _ [] = 0 poolsPoints (x:xs) ((a,b,c,d,e):t) | (x == a cd) = 1 + poolsPoints xs t | (x == a cd) = 1 + poolsPoints xs t | (x == a c==0 d==0) = 2 + poolsPoints xs t | (x == a c==d c0) = 3 + poolsPoints xs t | otherwise = 0 + poolsPoints [x] t Thanks Ryan _ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] FW: please help... small problem
hi I've attempted to cut down this module... but I cannot see where... can someone help... Ryan thanks From: [EMAIL PROTECTED]: Subject: FW: please help... small problemDate: Fri, 9 Nov 2007 21:57:30 + sorry heres the code I always do that. From: [EMAIL PROTECTED]: Subject: please help... small problemDate: Fri, 9 Nov 2007 21:44:35 + hi Is there anyway to cut down this code and to not use auxillary functons, but instead use pattern matching? The code basically splits up a list 'rslis' into a list of lists - but so each word is split up and the integers have been parsed. so [hi ryan 1,hi jeff 2] becomes [[hi,ryan 1], [hi,jeff, 2]].The code is far too long. I don't wanna use premade functions too much... pattern matching is required. Ryan The next generation of MSN Hotmail has arrived - Windows Live Hotmail Are you the Quizmaster? Play BrainBattle with a friend now! _ 100’s of Music vouchers to be won with MSN Music https://www.musicmashup.co.uk Football.hs Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] recursion issues...
hiya I was wondering how I would get the second function do recursively do the function for poolNews xs tried that and it fails. Ryan --Give wins, draws a rating. poolNews :: Result - PoolNews - PoolNews poolNews (a,b,c,d,e) (home,away,goaless,scoredraw) | c d = (home+1,away,goaless,scoredraw) | c d = (home,away+1,goaless,scoredraw) |(c == 0) (d == 0) = (home+1,away,goaless+1,scoredraw) | otherwise = (home,away,goaless,scoredraw+1) --Do for all Results poolNewsB :: Results - PoolNews poolNewsB (x:xs) = poolNews x (0,0,0,0) _ Celeb spotting – Play CelebMashup and win cool prizes https://www.celebmashup.com___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] please help... small problem
hi Is there anyway to cut down this code and to not use auxillary functons, but instead use pattern matching? The code basically splits up a list 'rslis' into a list of lists - but so each word is split up and the integers have been parsed. so [hi ryan 1,hi jeff 2] becomes [[hi,ryan 1], [hi,jeff, 2]].The code is far too long. I don't wanna use premade functions too much... pattern matching is required. Ryan _ 100’s of Music vouchers to be won with MSN Music https://www.musicmashup.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] FW: please help... small problem
sorry heres the code I always do that. From: [EMAIL PROTECTED]: Subject: please help... small problemDate: Fri, 9 Nov 2007 21:44:35 + hi Is there anyway to cut down this code and to not use auxillary functons, but instead use pattern matching? The code basically splits up a list 'rslis' into a list of lists - but so each word is split up and the integers have been parsed. so [hi ryan 1,hi jeff 2] becomes [[hi,ryan 1], [hi,jeff, 2]].The code is far too long. I don't wanna use premade functions too much... pattern matching is required. Ryan The next generation of MSN Hotmail has arrived - Windows Live Hotmail _ Get free emoticon packs and customisation from Windows Live. http://www.pimpmylive.co.uk Football.hs Description: Binary data ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] words function
hi I am trying to create a function that uses the words function... I am doing the same thing to each element in a list so I am using mapping techniques. Code... --Define the main first function rStrings2Results :: ([String] - String) - [[String]] - [String] rStrings2Results f(head:tail) = (f head : rStrings2Results f tail) I just want take a list and on the first member (hello my name is ryan) to say [(hello, my, name, is, ryan),..] using the words function. _ 100’s of Music vouchers to be won with MSN Music https://www.musicmashup.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Help please
hello, I am struggling with rose trees in Haskell. I need to construct an algebraic data type definition for family trees and a representation of the tree below. Also I need to construct a function that returns a persons children when given both a family tree and a name. The same is needed but for a getParents function. 1 2 3 4 5 6 7 8910 11 That is the rose tree that I seek. Where each number above is equivalent to (String, String) Data Tree a = Empty | Leaf a | Node a [(Tree a)] example :: Tree (String, String) example = Node (a,b) -- root node [ ...define tree.] -- end of tree _ 100’s of Music vouchers to be won with MSN Music https://www.musicmashup.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Rose Tree
Hello, I need help... I am having trouble with rose trees. 1 2 3 4 5 6 7 8910 11 That is the rose tree that I seek. Data Tree a = Empty | Leaf a | Node a [(Tree a)] example :: Tree (String, String) example = Node (a,b) -- root node [ ] -- end of tree What I want to do is create two functions that return either the children or parents of a given input, here a String. String - Tree - [String] I think _ The next generation of MSN Hotmail has arrived - Windows Live Hotmail http://www.newhotmail.co.uk___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Java - Haskell adjustment
Hi, its Ryan here... I've just come from an intensive course in java and have been thrown into the imperative world of haskell. The problem that I have is extremely simple in java but I am having trouble adjusting my old mindset. A multiset is a collection of items. Each item may occur one or more times in the multiset. All items are of the same type. The scenario we could use is a students' grades for their A levels: 3A, 4B and 2C grades for our pupil 'x'. A multiset may be implemented by a list... so ['A', 'A', 'A', 'B', 'B', 'B', 'B, 'C', 'C'] but this very ineffiecient and tedious. How might one set out into putting this into action thanks... Any help that complements my ideas is welcome _ Feel like a local wherever you go. http://www.backofmyhand.com___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
