On 7/18/2010 12:26 PM, Steven Watanabe wrote:
AMDG
Edward Diener wrote:
I found the BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF macro in the latest has_xxx.hpp of mpl on the trunk.
Is BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF ( and its corresponding BOOST_MPL_HAS_XXX_TEMPLATE_DEF ) scheduled to be added to Boost in an upcoming release ? I find it useful for TMP introspection in much the same way as BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF ( and its corresponding BOOST_MPL_HAS_XXX_TRAIT_DEF ).
It's currently in the release branch and should be released in 1.44.
That is good to hear but... My testing with VC9 and VC10 shows that if I pass too many tempate arguments I get a compiler failure: ---------------------------------------------------- #include <boost/mpl/has_xxx.hpp> struct AAType { template <class X> struct AAMemberTemplate { }; }; BOOST_MPL_HAS_XXX_TEMPLATE_DEF(AAMemberTemplate) has_AAMemberTemplate<AAType,int,int> yz; // error ---------------------------------------------------- error C2977: 'has_AAMemberTemplate' : too many template arguments see declaration of 'has_AAMemberTemplate' error C2133: 'yz' : unknown size error C2512: 'has_AAMemberTemplate' : no appropriate default constructor available etc. Of course I expect a BOOST_MPL_ASSERT failure for: BOOST_MPL_ASSERT((has_AAMemberTemplate<AAType,int,int>)) but not a compiler error. The Concept Traits Library also had a macro which worked similarly, but also failed for the same reason. When I discovered the implementation in the trunk version of MPL I had hopes that this was better. Sigh ! The code in the MPL is highly complicated, else I would spend the hours trying to understand it and perhaps fix it. But I hope that at least reporting my failure with VC9 and VC10 will help to get this working.