On Mon, May 2, 2011 at 11:39 AM, Gordon Woodhull <gordon@woodhull.com> wrote:
On May 2, 2011, at 10:58 AM, Stewart, Robert wrote:
If lexical_cast can be extended, then I think most of the features of this library should be made part of lexical_cast, but that would preclude the optimized conversions I suggested earlier (when one can forgo locales and manipulators). Thus far, history has indicated that such changes are not welcome, making a library like Boost.Convert necessary.
Along with Vladimir, I'd really like to kill this line of reasoning. Here's Kevlin's rationale, quoted in some earlier discussion. (It seems to have disappeared from the lexical_cast documentation since then.)
http://lists.boost.org/Archives/boost/2005/04/84917.php
- It is also worth mentioning future non-directions: anything that involves adding extra arguments for a conversion operation is not being considered. A custom keyword cast, such as lexical_cast, is intended to look like a built-in cast operator: built-in cast operators take only a single operand.
I actually find that pretty convincing, although I'd like to see something that looks as close to lexical_cast as possible.
I would also like to voice my support of Vladimir. Parsing XML or properties files is tremendously slow using lexical_cast because of all the exceptions when all you want is a default value if something is missing. We've been down this road before, discussing extending lexical_cast and it went nowhere for a decent reason. So Vladimir's only choice was to make Convert, yet people are still voting No over this. --Michael Fawcett