> import TextDisplay(textDisplay)
> import IOutilities(getCookedLine)

explain purpose, prompt for filename and retrieve,
read mark-up file, write display file

> main =
>   do
>     putStr msgPurpose
>     putStr promptFilename
>     markupFilename <- getCookedLine
>     markupFile <- readFile markupFilename
>     writeFile (markupFilename ++ displayFileExtension)
>               (textDisplay markupFile)
>     putStr msgQuit

messages of interaction

> msgPurpose = unlines[msgEmptyLine,
>                      "Write display file from mark-up",
>                      "   (name of display file same as",
>                      "   that of mark-up file, plus \"" ++
>                        displayFileExtension ++ "\" extension",
>                      msgEmptyLine]
> promptFilename = "Enter name of mark-up file: "
> msgQuit = unlines[msgEmptyLine,
>                   "Display file created"]
> msgEmptyLine = ""

> displayFileExtension = ".display"