Can someone provide an explanation of the following command?
typedef mpc_val_t*(*mpc_apply_t)(mpc_val_t*);
This is a type definition for mpc_apply_t, defining it as a pointer to a function accepting a pointer to a value of type mpc_val_t, and returning a pointer to a value of type mpc_val_t. The type mpc_val_t is defined elsewhere.