struct WrappedInt { int x; }; void ?{}(WrappedInt & this) { printf("constructing int\n"); this.x = 0; } void ?{}(WrappedInt & this, WrappedInt other) { printf("copy constructing int: %d\n", other.x); this.x = other.x; } void ?{}(WrappedInt & this, int x) { printf("constructing int: %d\n", x); this.x = x; } void ^?{}(WrappedInt & this) { printf("destructing int: %d\n", this.x); } void ?=?(WrappedInt & this, int x) { printf("assigning int: %d %d\n", this.x, x); this.x = x; } struct A { WrappedInt x, y, z; }; void ?{}(A & a) { // currently must define default ctor, since there's no "= default" syntax } void ?{}(A & a, int x) { printf("begin construct A\n"); printf("construct a.x\n"); (a.x){ x+999 }; printf("assign a.y\n"); a.y = 0; // not a constructor - default constructor will be inserted printf("end construct A\n"); } // z never constructed - will be automatically default constructed void ?{}(A & this, A other) { printf("begin copy construct A\n"); printf("copy construct this.x\n"); (this.x){ other.x }; printf("assign this.y\n"); this.y = other.y; // not a constructor - copy constructor will be inserted printf("end copy construct A\n"); } // z never constructed - will be automatically copy constructed A ?=?(A & this, A other) { printf("begin ?=? A\n"); this.x = other.x; this.y = other.y; this.z = other.z; printf("end ?=? A\n"); return this; } struct B { A a1, a2, a3; }; void ?{}(B & b) { printf("begin construct B\n"); printf("assign b.a2\n"); b.a2 = (A) { 2 }; printf("construct b.a1\n"); (b.a1){ 1 }; #ifdef ERR1 (b.a2){ b.a3 }; // error, b->a2 was used previously but is explicitly constructed #endif printf("end construct B\n"); } // a2, a3 never constructed - will be automatically default constructed void ^?{}(B & b) { b.a2 = (A) { 0 }; ^(b.a1){}; } // a2, a3 never destructed - will be automatically destructed int main() { printf("Before declaration of b1\n"); B b1; printf("Before declaration of b2\n"); B b2 = b1; printf("End of main\n"); }