I'd like to declare a function that returns a pointer to a function of the same type.
I would like to use it to implement state machines like the one below:
typedef event_handler_t (*event_handler_t)(event_t*); // compilation error
event_handler_t state2(event_t* e);
event_handler_t state1(event_t* e) {
switch(e->type) {
//...
case SOME_EVENT:
return state2;
//...
}
}
event_handler_t state2(event_t* e) {
switch(e->type) {
//...
case OTHER_EVENT:
return state1;
//...
}
}
//...
event_handler_t event_handler;
//...
event_handler(&e);
//...
I manage to work around the compliation error using structures as follows:
typedef struct event_handler {
struct event_handler (*func)(event_t *);
} event_handler_t;
But this makes return statment more complicated:
event_handler_t state2(event_t* e) {
{
event_handler_t next_handler = {NULL};
switch(e->type) {
//...
case OTHER_EVENT:
next_handler.func = state1;
break;
//...
}
return next_handler;
}
I wonder if there is a better way to create such function pointers in c.