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authorJasper Van der Jeugt <jaspervdj@gmail.com>2010-01-31 11:19:57 +0100
committerJasper Van der Jeugt <jaspervdj@gmail.com>2010-01-31 11:19:57 +0100
commit7afabf5c098efc2f0df482ab66d9091d7aa3bd23 (patch)
treea96a60459fa2d8fce6591d56d437d9da13c2b6fd /src/Text/Hakyll/Internal/CompressCss.hs
parent73d6b1d6614c3965afd96b710bfa79db94d2449e (diff)
downloadhakyll-7afabf5c098efc2f0df482ab66d9091d7aa3bd23.tar.gz
Better naming scheme.
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+-- | Module used for CSS compression. The compression is currently in a simple
+-- state, but would typically reduce the number of bytes by about 25%.
+module Text.Hakyll.Internal.CompressCss
+ ( compressCss
+ ) where
+
+import Data.List (isPrefixOf)
+
+import Text.Hakyll.Regex (substituteRegex)
+
+-- | Compress CSS to speed up your site.
+compressCss :: String -> String
+compressCss = compressSeparators
+ . stripComments
+ . compressWhitespace
+
+-- | Compresses certain forms of separators.
+compressSeparators :: String -> String
+compressSeparators = substituteRegex "; *}" "}"
+ . substituteRegex " *([{};:]) *" "\\1"
+ . substituteRegex ";;*" ";"
+
+-- | Compresses all whitespace.
+compressWhitespace :: String -> String
+compressWhitespace = substituteRegex "[ \t\n][ \t\n]*" " "
+
+-- | Function that strips CSS comments away.
+stripComments :: String -> String
+stripComments [] = []
+stripComments str
+ | isPrefixOf "/*" str = stripComments $ eatComments $ drop 2 str
+ | otherwise = head str : stripComments (tail str)
+ where
+ eatComments str' | null str' = []
+ | isPrefixOf "*/" str' = drop 2 str'
+ | otherwise = eatComments $ tail str'