input="n,n-n,n-,-n,n-n-n,the-endisnear"

remaining_line=input

while( remaining_line != "" )
     token=get_next_token(remaining_line)
     remaining_line=remaining_line - token
     case token in
          <number>)
               if( number within array bounds )
                    exec ${array[$number]}
               else
                    ERROR: number entered not within bounds
               end if
               ;;

          <number>-<number>)
               PASS=OK
               if( NOT num1 within array bounds )
                    ERROR: num1 not within bounds
                    PASS=not_OK
               end if
               if( NOT num2 within array bounds )
                    ERROR: num2 not within bounds
                    PASS=not_OK
               end if
               if( PASS == OK )
                    for( i=num1,i=num2,i++ )
                         exec ${array[$number]}
                    next
               end if
               ;;

          <number>-)
               ERROR: range clause not properly closed
               // you might want to change this to mean "from num to the end"
               ;;

          -<number>)
               ERROR: range clause not properly opened
               // you might want to change this to mean "from 1 to num"
               ;;

          all others)
               ERROR: cannot understand <token>
               ;;

     end case
end while