[Haskell-cafe] why does Data.Text.Lazy.IO.readFile return the internal type Data.Text.Lazy.Internal.Text, when Data.Text.IO.readFile returns plain IO Data.Text.Text?

*Main> :t Data.Text.IO.readFile Data.Text.IO.readFile :: FilePath -> IO T.Text but *Main> :t Data.Text.Lazy.IO.readFile Data.Text.Lazy.IO.readFile :: FilePath -> IO text-0.7.1.0:Data.Text.Lazy.Internal.Text why does the lazy version use the internal type, whereas the strict version of Text IO just using plain Data.Text type? and how can I get from internal type to regular type when using Data.Text? also the internal type doesn't appear to be reflected in the haddock: http://hackage.haskell.org/packages/archive/text/0.7.1.0/doc/html/Data-Text-... ghc-pkg list | grep -i text text-0.7.1.0 thanks for any help!