将递归转换为折叠?

我编写的代码循环遍历文件句柄的行,并对其执行任意操作。我不认为它应该是递归的——我能把它变成折叠动作吗?

谢谢

processHandle :: Handle -> (String->IO ()) -> IO ()
processHandle h fn = do
                   eof <- hIsEOF h
                   if eof then
                     return ()
                    else do
                      myLine <- hGetLine h
                      fn myLine
                      processHandle h fn