BARMEN ( nTRow, nLCol, nPosition, nAction, aBar, aMouse ) -> nChoice

   Activates a BarMenu. Colors are predefined via SetPref() !


   PARAMETERS:

       nTRow       Row, in which the Menu is shown
       nLCol       BeginningRow of the MenuBar
       @nPosition  Saves the active MenuItem (per Reference!)
       nAction     MenuItem is activated at once

       aBar        Array containing  Menudata (4 Dim.). Structure:

                <cText>, <nRet>, <lSelect>, <cDescription>, <nSpacing>

       aMouse      Array containing MouseFields (4 Dim.). Structure:

                   <nRow>, <nLColumn>, <nRColumn>, <nRet>


   RETURN VALUE:

   If it's a valid choice the 'aBar [x, nRet]' value, defined
   in the MenuArray, will be returned. ( Unless you defined a
   SubMenu-Array in it -> this will result in a PopUpMenu )

   The following ReturnValues are predefined ( SoundVis.ch )
   you shouldn't mess with them:

       B_ESC       0   will be returned if ESC is pressed
       B_LEFT     -1   Cursor Left  -> Internal, MenuItem +1
       B_RIGHT    -2   Cursor Right -> Internal, MenuItem -1
       B_QUIT     -3   Leaves the Menu
       B_MOUSE    -4   Internal, new Menu is chosen by Mouse
       K_MOUSE    255  KeyValue which the Mouse writes into the
                              Inkey-Buffer


   Structure of the MenuArray:

   Each element has at least 4 dimensions:
   ( You'll find the defines in SoundVis.ch )

   aBar [1, MEN_TEXT]  cText
        MenuText, the Hotkey is the one headed by an '~'

   aBar [1, MEN_RET]   nRet
        ReturnValue, can also be an array for a PopUpMenu

   aBar [1, MEN_SEL]   lSel
        is this Item selectable ? if so -> .T.

   aBar [1, MEN_DESC]  cDesc
        Description of the MenuItem, the Hotkey-Marker '~'
        will display the following word in a different color

   Optional:
   aBar [1, MEN_SPACE] nCols
        Using nCols you can set the spacing between the last and
        this MenuItem. This is used to right-bound the last
        MenuItem.


   Structure of the MouseArray:

   The MouseArray has 4 dimensions and contains information about
   Mouse 'Key-Fields'


   aMouse [1, MS_ROW ]  nRow
         When the Mouse is in this Row...

   aMouse [1, MS_LCOL]  nLColumn
         and from this Column....

   aMouse [1, MS_RCOL]  nRColumn
         up to this Column, then..

   aMouse [1, MS_RET ]  nRet
         MS_RET is returned by the Menu !


   Meaning: when you want quit your Programm through a 'CloseButton'
   on position 0,0 to 0,1 this will be your array:

            LOCAL aMouse := {{0, 0, 01, B_QUIT}}

   ( B_QUIT is predefined to -3 , the Menu is canceled and -3
    is returned. You can use it to finish a loop like:
    DO WHILE nRet # B_QUIT )