Re: [Boost-users] Visual Studio 2005 ptr_list visualizer?

Hi Bill, (please don't top post, thanks!)

I have written visualizers for the other pointer containers, but realize that I had forgotten about ptr_list. I previously posted the visualizer code for ptr_vector, ptr_map, ptr_multimap, ptr_set, ptr_multiset, and also array. If you don't have it I can easily post it again.

Thanks for sharing your work! Once the wiki + repository are ready, people will hopefully find things more easily.

I took a quick stab at ptr_list, but I think I may have run into a limitation (or bug) in the visualizer. It's not letting me cast the final expression to the templated parameter. I tried it with a direct cast and that worked, but it seems to lose the template information in the resulting expression.

The problem is in the expression ($T1*)$e._Myval. It seems that $T1 (the template parameter) is not valid at this point. If, for example the list is defined as ptr_list<int>, then the expression (int*)$e._Myval will work, but obviously we can't hard code that here. Any one have any ideas here?

Yes, this is a bit tricky... the problem is not $T1 being invalid in the context, it rather is in how pattern matching works. I suspect that the rule pattern matching is string-based. In this case, it is useful to look (via a watch) at the exact type being matched. In the case of ptr_list<int>, it is boost::ptr_list > which apparently matches your filter boost::ptr_list<*> since you see some effects in the watch window. Hence $T1 = "int,boost::heap_clone_allocator,std::allocator", which does not make sense after substitution. So, to fix your rule, it suffices to rewrite the pattern as boost::ptr_list<*,*,*> (in fact, boost::ptr_list<*,*> would work as well, justifying my above guess...but it is clearly not as clean). Cheers, Filip