convert.cpp: In member function ‘std::string Roman::ConversionContext::toR(mpz_class)’:
convert.cpp:127:43: error: passing ‘const std::map<Roman::ConversionContext::Numerals, const std::vector<char> >’ as ‘this’ argument of ‘std::map<_Key, _Tp, _Compare, _Alloc>::mapped_type& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](const key_type&) [with _Key = Roman::ConversionContext::Numerals; _Tp = const std::vector<char>; _Compare = std::less<Roman::ConversionContext::Numerals>; _Alloc = std::allocator<std::pair<const Roman::ConversionContext::Numerals, const std::vector<char> > >; std::map<_Key, _Tp, _Compare, _Alloc>::mapped_type = const std::vector<char>; std::map<_Key, _Tp, _Compare, _Alloc>::key_type = Roman::ConversionContext::Numerals]’ discards qualifiers [-fpermissive]
                     s, m_symbols[m_context]);
                                           ^
convert.cpp: In member function ‘std::string Roman::ConversionContext::reduce(std::string)’:
convert.cpp:167:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
make: *** [convert.o] Error 1