Function operator<

edrav2/eprj/boost/libs/python/test/operators.cpp:49–49

X& operator-=(X& l, X const& r) { l.set(l.value() - r.value()); return l; }

bool operator<(X const& x, X const& y) { return x.value() < y.value(); }
bool operator<(X const& x, int y) { return x.value() < y; }
bool operator<(int x, X const& y) { return x < y.value(); }