Here is a simple example. It decides whether or not the input properly represents a list of value ranges. The input syntax is approximately:

   [[ '!' ] <lo-num>] ['-' [<hi-num>]] \
      [',' [[ '!' ] <lo-num>] ['-' [<hi-num>]] ... ]

This page contains:

• the definitions
• The resulting header file
• the associated code file

See the usage page for a description of the attributes supported.

AutoGen Definitions fsm;
	
#if 0
Here is a simple example. It decides whether or not the input properly
represents a list of value ranges. The input syntax is approximately:

   [[ '!' ] <lo-num>] ['-' [<hi-num>]] \
      [',' [[ '!' ] <lo-num>] ['-' [<hi-num>]] ... ]
#endif

event  = comma, num,  dash, bang, eol;
state  = lonum, dash, hinum;
type   = looping;
method = case;
prefix = ex;
cookie = "void* cookie";

dash   = "-";
bang   = "!";
eol    = "End-Of-Line";
comma  = ",";

/*
 *  Define a transition for every valid transition.
 *  Specify the Transition_STate, the TransitionEVent and
 *  what the NEXT state will be.  A unique transition
 *  enumeration will be produced for each defined transition.
 */
transition = { tst = init; tev = num;  next = lonum; };
transition = { tst = init; tev = bang; next = init;  };
transition = { tst = dash; tev = num;  next = hinum; };

/*
 *  Dash transition.  Always go to 'dash' state, except when we are in
 *  the 'hinum' or 'dash' state.  Then, do the 'invalid' transition.
 */
transition = { tst = "*";   tev = dash; next = dash; },
  { tst = hinum, dash; tev = dash; ttype = invalid; next = invalid; };

/*
 *  Comma transition, other than in 'init'.  You cannot have two
 *  commas together and you cannot start with one.  Transitions out of
 *  "hinum" state require no processing.
 */
transition = { tst = "*";  tev = comma; next = init; },
  { tst = hinum; tev = comma; ttype = noop;    next = init; },
  { tst = init;  tev = comma; ttype = invalid; next = invalid; };

/*
 *  End of line transition, other than in 'init'.
 *  You cannot end with a comma or without any ranges specified.
 */
transition = { tst = "*";  tev = eol; next = done; },
  { tst = hinum; tev = eol; ttype = noop;    next = done; },
  { tst = init;  tev = eol; ttype = invalid; next = invalid; };

The resulting header file:

#ifndef AUTOFSM_EXAMPLE_FSM_H_GUARD
#define AUTOFSM_EXAMPLE_FSM_H_GUARD 1

/*
 *  Finite State machine States
 *
 *  Count of non-terminal states.  The generated states INVALID and DONE
 *  are terminal, but INIT is not  :-).
 */
#define EX_STATE_CT  4
typedef enum {
    EX_ST_INIT,    EX_ST_LONUM,   EX_ST_DASH,    EX_ST_HINUM,   EX_ST_INVALID,
    EX_ST_DONE
} te_ex_state;

/*
 *  Finite State machine transition Events.
 *
 *  Count of the valid transition events
 */
#define EX_EVENT_CT 5
typedef enum {
    EX_EV_COMMA,   EX_EV_NUM,     EX_EV_DASH,    EX_EV_BANG,    EX_EV_EOL,
    EX_EV_INVALID
} te_ex_event;

/*
 *  Run the FSM.  Will return EX_ST_DONE or EX_ST_INVALID
 */
extern te_ex_state
ex_run_fsm(
    void* cookie );

#endif /* AUTOFSM_EXAMPLE_FSM_H_GUARD */

And the associated code file: