Niels Dekker:
T& operator=(T arg) { arg.swap(*this); return *this; }
...
Is the choice between swap(arg) and arg.swap(*this)) just a matter of taste?
Yes, I think so. I was just saying that T& operator=( T arg ) { swap( arg ); return *this; } is the form I've seen used (by Dave Abrahams, I think*). It certainly looks more "idiomatic" (in the sense of being recognizable as an idiom as opposed to ordinary code) because of the unusual swap call. *) Turns out that I was right in thinking that. Dave's associative_vector submission: http://lists.boost.org/Archives/boost/2000/05/3200.php contains: Self& operator=(Self rhs) { swap(rhs); return *this; } // strong guarantee I was able to find a post by Valentin Bonnard also suggesting the same: http://tech.groups.yahoo.com/group/boost/message/5001 Incidentally: http://aspn.activestate.com/ASPN/Mail/Message/boost/1140338 "It doesn't compile with Borland C++Builder 4 or BCC 5.5. ... The next problem was associative_vector's assignment operator. Borland didn't recognise it as one and generated a default. Then it couldn't disambiguate the generated assignment operator and the one supplied. I changed this to Self& operator=(const Self &rhs) { Self temp(rhs); swap(temp); return *this; }" My memory is correct on this one, too. I'm not sure why BCC 5.5.1 didn't exhibit the problem in my tests.