lattejed

{-
The MIT License (MIT)

Copyright (c) 2103 Matthew Smith [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is

lattejed

{-
    Step 2
    (m>0) ATIONAL ->  ATE
    ...
    (m>0) BILITI  ->  BLE
-}
step2 :: String -> String
step2 str =
    if (not $ null sfxs') && (measure $ snd $ wordDesc $ stm (fst sfx)) > 0
    then swapsfx str (fst sfx) (snd sfx)

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getstem :: String -> String -> String
getstem str sfx = take (length str - length sfx) str

swapsfx :: String -> String -> String -> String
swapsfx str sfx [] = take (length str - length sfx) str
swapsfx str sfx sfx' = take (length str - length sfx) str ++ sfx'

step1a :: (String, String) -> String
step1a (str,_) = swapsfx str (fst sfxs') (snd sfxs')
    where sfxs' = head $ dropWhile (\ss -> not $ fst ss `isSuffixOf` str) sfxs

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measure :: (String, String) -> Int
measure (_,ds) =
    length $ filter (=='c') ds'
    where ds' = dropWhile (=='c') [head a | a <- group ds]

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# Vivake Gupta ([email protected])
# http://tartarus.org/martin/PorterStemmer/python.txt

def m(self):
        n = 0
        i = self.k0
        while 1:
            if i > self.j:
                return n
            if not self.cons(i):

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rotateR :: [a] -> [a]
rotateR [x] = [x]
rotateR xs = last xs : init xs

-- Make a pattern to match the consonants and vowels in a word where a cons is
-- not "aeiou" or y preceded by a cons e.g., "happy" -> ("happy", "cvccv")
wordDesc :: String -> (String, String)
wordDesc str =
    (str, [corv (a,b,i) | (a,b,i) <- zip3 str (rotateR str) [0..len]])
    where len = length str - 1

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rotateR :: [a] -> [a]
rotateR [x] = [x]
rotateR xs = last xs : init xs

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-- Make a pattern to match the consonants and vowels in a word where a cons is 
-- not "aeiou" or y preceded by a cons e.g., "happy" -> ("happy", "cvccv")
wordDesc :: String -> (String, String)
wordDesc str = (str, [corv (a,b,i) | (a,b,i) <- zip3 str (rotateR str) [0..len]])
    where len = length str - 1
          corv (a,b,i)
            | a == 'y' && i /= 0 && b `notElem` vs = 'v'            
            | a `elem` vs = 'v'
            | otherwise = 'c'
            where vs = "aeiou"

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def cons(self, i):
    """cons(i) is TRUE <=> b[i] is a consonant."""
    if self.b[i] == 'a' or self.b[i] == 'e' or self.b[i] == 'i' or self.b[i] == 'o' or self.b[i] == 'u':
        return 0
    if self.b[i] == 'y':
        if i == self.k0:
            return 1
        else:
            return (not self.cons(i - 1))
    return 1

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rotateR :: [a] -> [a]
rotateR [x] = [x]
rotateR xs = last xs : init xs