Finds each individual value in a comma separated values string.

To use it, call read_comma_separated_values$() with a string.
Then call it again in a loop with a null string and it will return each value one at a time. When there's no more values left, it returns "END OF STRING"

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    global csv_start as dword
global csv_values as string
function csv$(called_values as string)

   if len(called_values)
      csv_values = called_values
      csv_start = 1
      exitfunction ""
   endif

   local length as dword
   length = len(csv_values)

   if csv_start > length then exitfunction "END OF STRING"

   local finish as dword
   local return_value as string

   for finish = csv_start to length
      if mid$(csv_values, finish) = ","
         return_value = right$(left$(csv_values, finish - 1), finish - csv_start)
         csv_start = finish + 1
         exitfunction return_value
      endif
   next finish

   return_value = right$(csv_values, finish - csv_start)
   csv_start = finish
endfunction return_value