On Monday 11 November 2002 04:56 am, Aleksey Gurtovoy wrote: [snip my limited example] > Hmm, interesting, so if this actually worked, we would be happy: > [snip nifty-looking is_callable implementation] > > ?
Well, you need to do some trickery to make it work when R=void, but otherwise I think we would be _very_ happy if this worked. Is there a tweak to the core language that would guarantee such a thing? > > The reason I mention is_instantiable instead of __is_well_formed > > is that is_instantiable can keep a class template interface, whereas > > __is_well_formed would require a new grammar production. > > From http://aspn.activestate.com/ASPN/Mail/Message/1412095 I've got an > impression that implementors are not too concerned about it. > > After all, '__is_well_formed' might be as easy to implement as this: > > void process_is_well_formed( args ) > { > try > { > process_sizeof( args ); > args.expression_result = true; > } > catch (compiler_error const& ) > { > args.expression_result = false; > } > } > > :) At one time in GCC, checking for compilability was as easy as: cp_silent++; // instantiate the thing you want to check cp_silent--; Doug _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
