Last change
on this file since 23 was
2,
checked in by simon, 19 years ago
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A little anagram thingie got imported here.
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File size:
1.1 KB
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1 | -- anagram.hs: Program to find the anagrams of a word in a word list |
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2 | |
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3 | import Char |
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4 | import System |
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5 | import IO |
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6 | |
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7 | -- Remove one occurrence of an element from a list |
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8 | deleteOne e [] = [] |
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9 | deleteOne e (y:ys) |
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10 | | e == y = ys |
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11 | | otherwise = y : deleteOne e ys |
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12 | |
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13 | -- Test if the strings is an re-arrangements of each other |
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14 | anagram [] [] = True |
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15 | anagram [] ys = False |
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16 | anagram xs [] = False |
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17 | anagram (x:xs) ys = elem x ys && anagram xs (deleteOne x ys) |
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18 | |
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19 | printStrList = putStr . concat . map (++ "\n") |
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20 | |
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21 | main = do |
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22 | args <- getArgs |
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23 | case args of |
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24 | [string,file] -> do |
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25 | chars <- readFile file |
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26 | printStrList (filter (anagram string') (phrases chars)) |
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27 | where string' = filter isAlpha string |
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28 | phrases c = map (filter isAlpha) (lines c) |
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29 | [string] -> do |
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30 | chars <- getContents |
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31 | printStrList (filter (anagram string) (lines chars)) |
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32 | _ -> do |
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33 | putStr "Usage: " |
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34 | getProgName >>= putStr |
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35 | putStrLn " WORD [FILE]" |
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36 | putStrLn "List anagrams of WORD from FILE or standard input." |
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37 | exitWith (ExitFailure 1) |
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38 | |
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