ALENG()

  Short:
  ------
  ALENG() Actual length of an array, less trailing nil elements

  Returns:
  --------
  <aLength>  => Actual array length, less trailing NILs

  Syntax:
  -------
  ALENG(aTarget)

  Description:
  ------------
  Determines the actual length of <aTarget>, less
  trailing nils.

  Examples:
  ---------

   a := {1,2,3,4,5,nil,nil,nil}
   ?len(a)       // => returns 8
   ?aleng(a)     // => returns 5

  Notes:
  ------
  This was a C function in prior Super.Libs

  Source:
  -------
  S_ALENG.PRG