Re: [Boost-users] Proto: extending the example mixed.cpp

Kim Kuen Tang wrote:

Hi all,

i wnat to extend the example in the file mixed.cpp with an operator[]:

double operator []( std::ptrdiff_t i ) const { DereferenceCtx const deref = {}; AdvanceCtx adctx(i); //just shift the iterator with std::advance typename boost::result_of::type expr2 = Begin()(*this); proto::eval(expr2,adctx); return proto::eval(expr2, deref); } This works well.

However is it possible to let proto figure out what the result_type of this function is?

I've tried to program in this way.

typedef typename boost::result_of::type Expr2; typedef typename proto::result_of::eval::type <snip>

You probably need something like this: typedef typename boost::remove_reference< typename boost::result_of::type >::type Expr2; typedef typename proto::result_of::eval::type result_type; HTH, -- Eric Niebler BoostPro Computing http://www.boostpro.com