Re: [Boost-users] [variant] ideas needed

AMDG Olaf wrote:

That's correct. If it contains a double the string value is empty.

...

The variant cannot contain a string that is not "NA"

struct available : public boost::static_visitor<bool> { bool operator()( const double&) const { return true; }

bool operator()( const string& lhs) const { assert(lhs == "NA");

return false; //??? } };

May this work? There is always a string - empty or holding "NA".

I don't quite understand. variant holds either a double or a string at any one time, never both. If the variant holds a double then the overload of operator() for double will be called, if a string then the overload for string will be called instead. In Christ, Steven Watanabe