Re: [boost] safe-bool CRTP class

Subject: Re: [boost] safe-bool CRTP class
From: Bryce Lelbach (blelbach_at_[hidden])
Date: 2011-05-27 16:42:19

Such a class is already in Boost, in two places:

/home/wash/development/boost-trunk-wc/boost/range/detail/safe_bool.hpp
/home/wash/development/boost-trunk-wc/boost/spirit/core/safe_bool.hpp
/home/wash/development/boost-trunk-wc/boost/spirit/home/classic/core/safe_bool.hpp
/home/wash/development/boost-trunk-wc/boost/spirit/include/classic_safe_bool.hpp

smart_ptr also has a version.

Attached is a modified version of this that incorporates portability code from
the smart_ptr version into the variant of the spirit safe_bool that Hartmut and
I use at work.

I like to have a macro for this, so I have an operator that's convertible to the
safe_bool class, which is itself convertible to bool (this avoids problem with
the need for "typename" in the macro in certain contexts). The safe_bool class
is itself convertible to bool.

Feel free to incorporate any of this code into whatever comes out of this thread.

-- 
Bryce Lelbach aka wash
boost-spirit.com
px.cct.lsu.edu
github.com/lll-project