如何修复错误“Variable not in scope: md5 :: C8.ByteString -> a0”?

各位好。



git clone https://github.com/ian-ross/blog ian-ross-blog

cd ian-ross-blog

cd build

i modified blog.hs:

delete "import System.Locale (defaultTimeLocale)"

change "import Data.Time.Format (formatTime)" to be

"import Data.Time.Format (formatTime, defaultTimeLocale)"

then i ran "ghc --make blog.hs",

root@AR:/usr/local/ian-ross-blog/build# ghc --make blog.hs

[1 of 2] Compiling TikZ ( TikZ.hs, TikZ.o )

TikZ.hs:148:23: error:

Variable not in scope: md5 :: C8.ByteString -> a0

root@AR:/usr/local/ian-ross-blog/build#

那么，如何修复错误“ Variable not in scope: md5 :: C8.ByteString -> a0 ”?