Revision 72747d91 src/Ganeti/Utils.hs

b/src/Ganeti/Utils.hs
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  , chompPrefix
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  , wrap
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  , trim
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  , defaultHead
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  , exitIfEmpty
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  ) where
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import Data.Char (toUpper, isAlphaNum, isDigit, isSpace)


  		





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-- strings.


  		





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trim :: String -> String


  		





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trim = reverse . dropWhile isSpace . reverse . dropWhile isSpace


  		





  
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-- | A safer head version, with a default value.


  		





  
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defaultHead :: a -> [a] -> a


  		





  
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defaultHead def []    = def


  		





  
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defaultHead _   (x:_) = x


  		





  
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-- | A 'head' version in the I/O monad, for validating parameters


  		





  
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-- without which we cannot continue.


  		





  
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exitIfEmpty :: String -> [a] -> IO a


  		





  
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exitIfEmpty _ (x:_) = return x


  		





  
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exitIfEmpty s []    = exitErr s


  		












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