The tutorial does a great job of explaining why this is interesting: http://hack...

TazeTSchnitzel · on Jan 30, 2015

Are those types just aliases of String?

throwaway283719 · on Jan 30, 2015

No. For example, a FilePath is (after resolving a few other type aliases)

  data Root
	  = RootPosix
	  | RootWindowsVolume Char
	  | RootWindowsCurrentVolume

  data FilePath = FilePath
	  { pathRoot        :: Maybe Root
	  , pathDirectories :: [String]
	  , pathBasename    :: Maybe String
	  , pathExtensions  :: [String]
	  }

marcosdumay · on Jan 30, 2015

What do you mean by "alias"?

Path carries String-like information, it can even be easily converted to and from strings. Yet, it's a strong type that won't let you write something like 'path </> file_contents' (although, with overloaded strings, you can do 'path </> "file_name"').

UTCTime is not String-like.