-- game header information {{{
getFormat   = do
    prop <- consumeSingle "FF"
    ff   <- maybe (return 1) number prop
    when (ff /= 4) (dieWithPos FormatUnsupported (maybe (newPos "FF_missing" 1 1) position prop))
    return ff
getFormat   = do
    prop <- consumeSingle "FF"
    ff   <- maybe (return 1) number prop
    when (ff /= 4) (dieWithPos FormatUnsupported (maybe (newPos "FF_missing" 1 1) position prop))
    return ff
getFormat   = do
    prop <- consumeSingle "FF"
    ff   <- maybe (return 1) number prop
    when (ff /= 4) (dieWithPos FormatUnsupported (maybe (newPos "FF_missing" 1 1) position prop))
    return ff