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// This examples demonstrates default method implementations.
#include <interface99.h>
#include <stdio.h>
#define Droid_IFACE \
vfunc(const char *, name, void) \
vfuncDefault(void, turn_on, Droid droid)
interface(Droid);
// The default implementation of `Droid::turn_on`.
void Droid_turn_on(Droid droid) {
// A default implementation can access other methods through an interface object.
printf("Turning on %s...\n", droid.vptr->name());
}
// C-3PO implementation
// ============================================================
typedef struct {
char dummy;
} C_3PO;
const char *C_3PO_name(void) {
return "C-3PO";
}
// Use the default implementation of `Droid::turn_on` automatically.
impl(Droid, C_3PO);
// R2-D2 implementation
// ============================================================
typedef struct {
char dummy;
} R2_D2;
const char *R2_D2_name(void) {
return "R2-D2";
}
void R2_D2_turn_on(Droid droid) {
// A default implementation can be called from a custom one.
Droid_turn_on(droid);
puts("Waaaaoow!");
}
// Use a custom implementation for `Droid::turn_on`.
#define R2_D2_turn_on_CUSTOM ()
impl(Droid, R2_D2);
// Test
// ============================================================
/*
* Output:
* Turning on C-3PO...
* Turning on R2-D2...
* Waaaaoow!
*/
int main(void) {
Droid c_3po = DYN_LIT(C_3PO, Droid, {0});
VCALL_OBJ(c_3po, turn_on);
Droid r2_d2 = DYN_LIT(R2_D2, Droid, {0});
VCALL_OBJ(r2_d2, turn_on);
return 0;
}
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