Difference between revisions of "Functii din Prelude, A-F"
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− | [[Category:Ro]] |
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− | [[Image:Haskelllogo-small-flag-RO-8.jpg|center|Haskell - Un limbaj functional pur]] |
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− | Lista de functii des folosite, cu nume de la A la F. |
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− | Pentru a vedea un exemplu de folosire (si tipul fiecarei functii) cautati numele ei mai jos pe pagina, cu Find-ul browser-ului. |
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− | abs - valoarea absoluta |
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− | all - predicatul e adevarat pe toata lista de argumente ? |
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− | and - conjunctie generalizata pe o lista de valori de tip Bool |
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− | any - exista o valoare pe lista care satisface predicatul (in engleza aceste intrebari se pun cu any) |
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− | atan - arctangenta |
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− | break - rupe o lista inaintea locului/elementului care satisface un predicat |
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− | ceiling - rotunjirea superioara la un intreg |
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− | chr - caracterul cu acel cod ascii, conversie numar - caracter |
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− | concat - concatenarea unui grup de liste , dat ca lista :) de liste |
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− | cos - cosinusul |
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− | digitToInt - transforma caracterul (daca e cifra) cifra in valoarea lui |
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− | div - impartirea intreaga |
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− | drop - arunca primele dintr-o lista |
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− | dropWhile - arunca primele care indeplinesc conditia |
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− | -- folositor la a ajunge la primele elemente semnificative daca pui conditia invers |
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− | elem - apartine listei |
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− | error - genereaza eroare si poate avea orice tip, folositi-o deci oriunde |
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− | exp - e(x) |
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− | flip - schimba ordinea argumentelor unei functii cu doua arg |
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− | filter - alege ce satisface predicatul, din lista data |
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− | ---- |
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− | <haskell> |
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− | :t abs |
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− | abs :: Num a => a -> a |
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− | Prelude> abs -9 |
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− | ERROR - Illegal Haskell 98 class constraint in inferred type |
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− | *** Expression : abs - 9 |
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− | *** Type : (Num a, Num (a -> a)) => a -> a |
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− | |||
− | Prelude> abs (-9) |
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− | 9 |
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− | Prelude> abs (-9.3) |
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− | 9.3 |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t all |
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− | all :: (a -> Bool) -> [a] -> Bool |
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− | Prelude> all isDigit "12234678" |
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− | True |
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− | Prelude> all isDigit "danu" |
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− | False |
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− | Prelude> |
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− | ---- |
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− | lse |
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− | Prelude> :t and |
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− | and :: [Bool] -> Bool |
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− | Prelude> and [True,True ,True] |
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− | True |
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− | Prelude> and [True,True ,True,False] |
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− | False |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t atan |
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− | atan :: Floating a => a -> a |
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− | Prelude> |
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− | Prelude> 4 * atan 1 |
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− | 3.14159 |
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− | ---- |
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− | relude> :t break |
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− | break :: (a -> Bool) -> [a] -> ([a],[a]) |
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− | Prelude> break isDigit "R2D2" |
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− | ("R","2D2") |
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− | Prelude> break isDigit "3PO" |
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− | ("","3PO") |
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− | Prelude> |
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− | Prelude> break isSpace "La Multi Ani 2008!" |
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− | ("La"," Multi Ani 2008!") |
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− | Prelude> |
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− | Prelude> break (==0) [5,24,23,2,1,0,-1] |
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− | ([5,24,23,2,1],[0,-1]) |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t ceiling |
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− | ceiling :: (RealFrac a, Integral b) => a -> b |
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− | Prelude> ceiling 2.2 |
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− | 3 |
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− | Prelude> ceiling 1.242 |
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− | 2 |
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− | Prelude> ceiling 1.42 |
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− | 2 |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t chr |
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− | chr :: Int -> Char |
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− | |||
− | Prelude> chr 66 |
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− | 'B' |
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− | Prelude> chr 65 |
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− | 'A' |
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− | Prelude> chr 32 |
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− | ' ' |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t concat |
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− | concat :: [[a]] -> [a] |
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− | Prelude> concat ["La", "Multi", "Ani","!"] |
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− | "LaMultiAni!" |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t cos |
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− | cos :: Floating a => a -> a |
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− | Prelude> cos 0 |
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− | 1.0 |
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− | Prelude> |
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− | ---- |
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− | relude> digitToInt "0" |
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− | ERROR - Type error in application |
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− | *** Expression : digitToInt "0" |
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− | *** Term : "0" |
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− | *** Type : String |
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− | *** Does not match : Char |
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− | |||
− | Prelude> digitToInt '0' |
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− | 0 |
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− | Prelude> digitToInt '1' |
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− | 1 |
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− | Prelude> digitToInt '2' |
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− | 2 |
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− | Prelude> digitToInt '3' |
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− | 3 |
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− | Prelude> digitToInt '4' |
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− | 4 |
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− | Prelude> digitToInt 'u' |
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− | Program error: Char.digitToInt: not a digit |
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− | |||
− | Prelude> |
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− | ---- |
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− | Prelude> :t div |
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− | div :: Integral a => a -> a -> a |
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− | Prelude> 10 `div` 3 |
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− | 3 |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t drop |
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− | drop :: Int -> [a] -> [a] |
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− | Prelude> drop 2 ["La", "Multi", "Ani","!"] |
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− | ["Ani","!"] |
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− | Prelude> |
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− | ----- |
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− | Prelude> :t dropWhile |
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− | dropWhile :: (a -> Bool) -> [a] -> [a] |
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− | Prelude> dropWhile (==0) [0,0,0,0,1,2,3,4,0,0,1,2] |
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− | [1,2,3,4,0,0,1,2] |
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− | Prelude> |
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− | Prelude> :t elem |
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− | elem :: Eq a => a -> [a] -> Bool |
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− | Prelude> elem "!" ["La", "Multi", "Ani","!"] |
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− | True |
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− | Prelude> elem "2008" ["La", "Multi", "Ani","!"] |
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− | False |
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− | Prelude> elem "2000" ["La", "Multi", "Ani","!"] |
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− | False |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t error |
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− | error :: String -> a |
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− | Prelude> error "Stop the train!" |
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− | ERROR - Cannot find "show" function for: |
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− | *** Expression : error "Stop the train!" |
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− | *** Of type : a |
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− | Prelude> error "Stop the train!" :Char |
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− | ERROR - Undefined constructor function "Char" |
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− | Prelude> error "Stop the train!" :: String |
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− | " |
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− | Program error: Stop the train! |
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− | |||
− | Prelude> |
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− | ---- |
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− | Prelude> :t exp |
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− | exp :: Floating a => a -> a |
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− | Prelude> exp 1 |
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− | 2.71828 |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t flip |
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− | flip :: (a -> b -> c) -> b -> a -> c |
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− | Prelude> (flip (>)) 1 2 |
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− | True |
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− | Prelude> |
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− | ---- |
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− | Prelude> :t filter |
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− | filter :: (a -> Bool) -> [a] -> [a] |
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− | Prelude> filter (>2) [1,2,3,4,1] |
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− | [3,4] |
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− | Prelude> |
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− | </haskell> |
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− | |||
− | ---- |
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− | Pagina indexata la indexul [[Category:Ro]] [http://www.haskell.org/haskellwiki/Category:Ro Categories:Ro] |
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− | ---- |
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− | [http://www.haskell.org/haskellwiki/Ro/Haskell <= Inapoi la pagina principala Ro/Haskell. ]<br> <br> |
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− | [http://www.haskell.org/haskellwiki/Intrebarile_incepatorului <'''-''' Inapoi la Intrebarile incepatorului Ro/Haskell. ] |