While it's generally considered a bad practice to provide implicit conversions, I think it would be good to provide such a conversion for the boost::format class. [snip] Having been bit far too many times by bad implicit conversions, I would vote against such a change. I don't see why one shouldn't pass in a format object to a function (possibly for the function to add one argument to the format object).
I still think that providing a member function with(), rather than an operator % would have been better. Then one could write: string s = format("%1%").with(10).str(); which seems does seem neater than: string s = (format("%1%") % 10).str(); If we are to change boost::format, I would prefer to add such a member function than an implicit conversion. -- Martin Bonner Martin.Bonner@Pitechnology.com Pi Technology, Milton Hall, Ely Road, Milton, Cambridge, CB4 6WZ, ENGLAND Tel: +44 (0)1223 441434