src/Text/Hakyll/CompressCSS.hs · hakyll

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hakyll/src/Text/Hakyll/CompressCSS.hs

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1module Text.Hakyll.CompressCSS

2 ( compressCSS

3 ) where

5import Data.List (isPrefixOf)

7import Text.Hakyll.Regex (substituteRegex)

9-- | Compress CSS to speed up your site.

10compressCSS :: String -> String

11compressCSS = compressSeparators

12 . stripComments

13 . compressWhitespace

15-- | Compresses certain forms of separators.

16compressSeparators :: String -> String

17compressSeparators = substituteRegex "; *}" "}"

18 . substituteRegex " *([{};:]) *" "\\1"

19 . substituteRegex ";;*" ";"

21-- | Compresses all whitespace.

22compressWhitespace :: String -> String

23compressWhitespace = substituteRegex "[ \t\n][ \t\n]*" " "

25-- | Function that strips CSS comments away.

26stripComments :: String -> String

27stripComments [] = []

28stripComments str

29 | isPrefixOf "/*" str = stripComments $ eatComments $ drop 2 str

30 | otherwise = head str : stripComments (tail str)

31 where

32 eatComments str' | null str' = []

33 | isPrefixOf "*/" str' = drop 2 str'

34 | otherwise = eatComments $ tail str'