[boost] lexical_cast with default value

Hi all, I recently discovered lexical_cast, and it's very nice and elegant. I'd like to put in a feature request, though: the ability to use a default value rather than throwing an exception on conversion failure. Basically, it would take a second argument that would be the value returned if the conversion fails. This could be used directly in the example, like: std::vector<short> args; while(*++argv) { args.push_back(lexical_cast<short>(*argv, 0)); } This eliminates the throwing and catching of an exception for cases where conversion failure is not an exceptional. I've attached a patch to lexical_cast.hpp found in Boost 1.32.0 -Dave