Table 4 Optimized state transition table for DOS filename

  State  Substate  Target  True   False    Action   BadFcn
-------------------------------------------------------------
    A       0        a       1     ERR     pushchar  errmsg
    B       1        x       1      2      pushchar   skip
            2       DOT      4      3      pushchar   skip
            3        e      OUT    ERR     pushchar  errmsg
    C       4        x       5     ERR    savetoken  errmsg
    D       5        x       7      6      pushchar   skip
            6        e      OUT    ERR    savetoken  errmsg
    E       7        x       6      6      pushchar   skip