The pecl package 'operator' (http://pecl.php.net/package/operator)
sounds like what you might be looking for.
Wow, great! All I have to do is to implement a __assign_concat() method?
Yep, atm you can refer to the test files included in the package (no other docs yet).
Patrick also blogged up a nice summary:
http://blog.ghostwhowalksinside.org/archives/2006/programming/php/operator-magic which includes objectified string handling and one particularly frightening use of the mod operator...
Why this is not in the core?
Because PHP is not C++ :) Not to mention this is about two weeks old and very experimental. :)
And what is 'Plan A'? ;)
There are two ways to ask an object for a property. Either is sufficient for operator's needs, but the first version is preferred since it's less likely to cause an unnecessary duplication.
-Sara