Transferred from the old wiki, most of the issues below should be converted into tickets at some point.

Short-term TODO list

• transform on maps should not require providing an inserter (​http://article.gmane.org/gmane.comp.lib.boost.user/27842)
• ADL barrier technique needs to be applied to all MPL sequences (​http://article.gmane.org/gmane.comp.lib.boost.devel/115679/)
• GCC vector<...> performance problem (​http://search.gmane.org/?query=mpl+begin+vector+performance+problem&group=gmane.comp.lib.boost.devel&sort=relevance).
• Compilation failure with GCC: make_variant_over and vector (​http://thread.gmane.org/gmane.comp.lib.boost.user/9741).
• vector_c, range_c et al. don't work with enumeration types:
  • ​http://article.gmane.org/gmane.comp.lib.boost.devel/116940
  • ​http://thread.gmane.org/gmane.comp.lib.boost.user/9219
• at<AssocSeq,Key,Default> form is not supported (contrary to the docs, ​http://thread.gmane.org/gmane.comp.lib.boost.user/9597).
• transform fails if passed two sequences of different sizes (​http://thread.gmane.org/gmane.comp.lib.boost.user/10364).
• warnings in long_<MAX_LONG> etc. (​http://article.gmane.org/gmane.comp.lib.boost.devel/121580)
• weird interaction between set and map headers (​http://article.gmane.org/gmane.comp.lib.boost.devel/132994/)
• pop_back< range_c<int,0,10> > doesn't work, contrary to the book (​http://article.gmane.org/gmane.comp.lib.boost.user/20386/).

• apply + lambda + BOOST_MPL_LIMIT_METAFUNCTION_ARITY + 1 issue (​http://thread.gmane.org/gmane.comp.lib.boost.user/9699).
• Implement lambda scoping as per ​http://article.gmane.org/gmane.comp.lib.boost.devel/116000/.
• Document pair_view.
• contains<set,k> as a synonym for has_key<set,k>.
• contains_c<s,N> === find_if< s, equal_to< _1, integral_c<s::value_type,N> > > where s is a sequence of integral constants.
• Double-check type_traits TR1 changes (​http://article.gmane.org/gmane.comp.lib.boost.devel/117026/).
• Modify empty_base to handle non-default initialization (​http://groups-beta.google.com/group/comp.lang.c++.moderated/msg/8f72194e7bc0afb4).
• MSVC preprocessor fixes: replace __LINE__ with __COUNTER__, in <boost/mpl/assert.hpp> and possibly elsewhere (​http://thread.gmane.org/gmane.comp.lib.boost.user/7922).
• for_each variant which allows to (efficiently) terminate the iteration (​http://article.gmane.org/gmane.comp.lib.boost.user/13843)

Long-term TODO list

• Consider full laziness as per Vesa's posts (​http://search.gmane.org/?query=+Lazy+Metaprogramming+Library&group=gmane.comp.lib.boost.devel&sort=relevance).
• Improve diagnostics; in particular, introduce (optional) concept checking for all template parameters, e.g.:

          template< 
                typename Seq
              , typename T
              BOOST_MPL_AUX_PARAMS_CONCEPT_CHECK( is_forward_sequence<Seq>::value )
              >
          struct find
          {
              // ...
          };
  

• Tools for composing inlined (run-time) algorithms:
  • ​http://lists.boost.org/MailArchives/boost/msg55203.php
  • ​http://groups-beta.google.com/group/comp.lang.c++.moderated/msg/1319e53af9955115?dmode=source
• Integration with Alexander Nasonov's "overloads" library (​http://article.gmane.org/gmane.comp.lib.boost.devel/116517, ​http://article.gmane.org/gmane.comp.lib.boost.devel/117532/)
• Move (and document!) Eric Friedman's lambda_match from Sandbox to the main CVS.
• Officially adopt one of the compile-time rational / fixed numbers implementations.

Maintanance items

• Remove direct dependency on Boost.Config; in particular, replace all <boost/config.hpp> includes with a corresponding <boost/mpl/aux_/config/<i>specific_condig_header.hpp</i>>

Miscellaneous Ideas

• Self-recursive lambdas:

          if_< equal<N,int_c<0> >
                N
              , plus<
                    bitand_<N, int_c<1> >
                  , self< shift_right_c<N,3> > // self-recursion
                  >
              >
  

• "Round" lambda, see:
  • ​http://thread.gmane.org/gmane.comp.lib.boost.devel/77267
  • ​http://thread.gmane.org/gmane.comp.lib.boost.devel/77359
  • ​http://thread.gmane.org/gmane.comp.lib.boost.devel/77360
  • ​http://thread.gmane.org/gmane.comp.lib.boost.devel/77361
  • And also ​http://thread.gmane.org/gmane.comp.lib.boost.devel/117077
• make fold result a sequence, see:
  • ​http://article.gmane.org/gmane.comp.lib.boost.devel/119087