72 lines
1.5 KiB
Haskell
72 lines
1.5 KiB
Haskell
module Toks where
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import Data.Char
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import Data.Function
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import Data.List
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type Tok = String
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escape :: Char -> String
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escape '\\' = "\\\\"
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escape '\n' = "\\n"
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escape x = pure x
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unescape :: String -> String
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unescape [] = []
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unescape ('\\':'\\':xs) = '\\' : unescape xs
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unescape ('\\':'n':xs) = '\n' : unescape xs
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unescape ('\\':_) = error "bad escape on input"
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unescape (x:xs) = x : unescape xs
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tok ('.':_) = True
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tok ('/':_) = True
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tok _ = False
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markSpace :: String -> Tok
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markSpace [] = error "empty token"
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markSpace s@(c:_)
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| isSpace c = '.' : s
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| otherwise = '/' : s
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unmarkSpace :: Tok -> String
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unmarkSpace ('.':s) = s
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unmarkSpace ('/':s) = s
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unmarkSpace _ = error "bad space marking on input"
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space :: Tok -> Bool
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space ('.':_) = True
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space _ = False
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joinSpaces :: [Tok] -> [Tok]
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joinSpaces [] = []
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joinSpaces (a@('.':as):xs) =
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case joinSpaces xs of
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(('.':bs):xs') -> ('.' : (as ++ bs)) : xs'
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xs' -> a : xs'
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joinSpaces (x:xs) = x : joinSpaces xs
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splitCategory :: String -> [Tok]
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splitCategory = make . groupBy ((==) `on` generalCategory)
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simpleCategory :: Char -> Int
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simpleCategory c
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| isSpace c = 0
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| isAlpha c = 1
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| isNumber c = 2
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| otherwise = 3
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splitSimple :: String -> [Tok]
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splitSimple = make . groupBy ((==) `on` simpleCategory)
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make :: [String] -> [Tok]
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make = map (concatMap escape . markSpace)
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glue :: [String] -> String
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glue = concatMap (unmarkSpace . unescape)
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fromFile :: String -> [Tok]
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fromFile = lines
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toFile :: [Tok] -> String
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toFile = unlines
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