SACHOICE()

  Short:
  ------
  SACHOICE() Achoice replacement, uses TBROWSE, codeblock

  Returns:
  --------
  <nSelection> => selection, 0 if none

  Syntax:
  -------
  SACHOICE(nTop,nLeft,nBottom,nRight,aOptions,[bKeyBlock],[nStart],[@nRow],;
           [nMRow, nMCol],[bMouse])

  Description:
  ------------
  This semi-replaces ACHOICE() by using TBROWSE
  instead, and by accepting an exception codeblock instead of a user
  defined function.

  <nTop,nLeft,nBottom,nRight> are the dimensions.

  <aOptions> is the array. It need not be of type
  Character.

  First-letter presses go to the next matching letter
  of the next character-type element.
  Up/down/home/end/pageup/pagedown are used to position the
  cursor. ENTER returns the current selection. Escape returns 0.

  The screen is not saved and restored. This is a
  building block function, like ACHOICE(), so save and restore the
  screen, draw a box around it, etc, as you would ACHOICE().

  [bKeyBlock] a codeblock which will be executed if an
  exception key is received (any key not otherwise meaningful). The
  codeblock will be evaluated and will be passed:

           1. current element #
           2. exception key value
           3. the tbrowse object

  as parameters.

  [nStart] is an optional starting element. Default is 1.
  [@nRow] is an optional starting row. Default is 1. Pass by reference
  to retain value between calls.

  [nMRow, nMCol]  (new in 3.5) Directs sachoice() to draw
  the "[.][.]" for mouse up/down at nMrow, nMCol, and to be aware of mouse
  clicks on these buttons. (the screen under the arrows is saved/restored)

  [bMouse] is a codeblock to evaluate mouse clicks other than those
  meaningful to sachoice(). The codeblock is evaluated as follows:
            eval(bMouse,mouserow, mousecolumn)

  Examples:
  ---------
   USE CUSTOMER

   aFlds       := afieldsx()
   bExcept     := {|e,k|msg("You pressed ",str(k))}
   ?SACHOICE(10,10,20,12,aFlds,bExcept)

   //to retain element and position between calls
   nSelect := 1
   nRow    := 1
   aMeals   := {"Pizza","Chicken","Chinese"}
   while nSelect > 0
     nSelect  := sachoice(10,10,20,20,aMeals,nil,nSelect,@nRow)
     // code
   endif

  Notes:
  -------
  This will be a lot easier to mouse-ize than ACHOICE.
  (or is that RAT-ify..)

  Source:
  -------
  S_ACHOI.PRG