Just sent the message below to clc++m. Any comments are welcome. There's a library that I understand is being proposed for Boost: http://www.codeproject.com/vcpp/stl/PGIL.asp It does useful things, but it runs straight against the commonly given advice (with which I happen to agree) that one should not override operator, unless using expression templates that ensure left-to-right evaluation. So now, in the referenced article, the author makes the comment: " Overloading operator comma is sometimes viewed as a bad practice [3]. However, it has been done with success in eg. the Generative Matrix Computation Library and Blitz to initialize matrices (see [4]) and [5]). The Initialization Library overloads the comma operator in a safe manner by letting set_cont and set_map return an object that is responsible for the initialization. Therefore it takes explicit action from the programmer to begin using the overloaded operator,(). " I think the mentioned libraries do employ expression templates, while the initialization library does not. So I am unsatisfied. Anyone here can soothe my concerns? Is overloading the comma operator considered harmless after all? Andrei