1 diff --git i/libbase/accumulator.h w/libbase/accumulator.h
2 index 694cbd2..876c669 100644
3 --- i/libbase/accumulator.h
4 +++ w/libbase/accumulator.h
7 #include <boost/program_options/value_semantic.hpp>
8 #include <boost/any.hpp>
9 +#include <boost/version.hpp>
13 @@ -61,6 +62,11 @@ public:
14 virtual unsigned min_tokens() const { return 0; }
15 virtual unsigned max_tokens() const { return 0; }
17 +#if BOOST_VERSION >= 105900
18 + /// There are no tokens, so this is indifferent.
19 + virtual bool adjacent_tokens_only() const { return false; }
22 /// Accumulating from different sources is silly.
23 virtual bool is_composing() const { return false; }