On Thu, Dec 11, 2008 at 6:00 PM, Gordon Woodhull <gordon@woodhull.com> wrote:
I was hoping that we will also be possible to specify lambdas at compile time, which is more efficient because boost::function incurs cost equivalent to a virtual method call (it prohibits inlining and dereferences a pointer). And there is the cost of storing the function pointer too...
I am imagining things like constrained_value<int, decltype(_1>0 && !bind(isnan,_1))>.
In my perfect imaginary world this would be a zero-size predicate which is default constructable because it carries no data. Thus the expression doesn't need to be duplicated on construction and is stored entirely in the constrained_value typedef.
0 might have to be construct<mpl::integral_c<0> >() :-D
I'm sure there are 1000 things wrong with this, just fantasizing... I guess this also falls into the bin of "what's the perfect predicate library?"
I was able to do something like this with phoenix: http://thread.gmane.org/gmane.comp.parsers.spirit.general/12018 There were some challenges, but what did work worked nicely. Stjepan