On 8/26/2011 3:32 AM, John Maddock wrote:
BTW I do specify a proto grammar, and only enable the operators I need on a case by case basis, in this case though I would need to restrict the grammar so that proto's shift operators are only enabled for RHS arguments of integer type. Is that possible?
Yes. Can you post your grammar?
Pretty basic at present, need to refine those terminals a bit more! :
Yes!
struct big_number_grammar : proto::or_< proto::terminal< proto::_ >
You correctly identified your problem with the stream operators. std::cout matches because of the above line, and it shouldn't.
, proto::plus< big_number_grammar, big_number_grammar > , proto::multiplies< big_number_grammar, big_number_grammar > , proto::minus< big_number_grammar, big_number_grammar > , proto::divides< big_number_grammar, big_number_grammar > , proto::unary_plus< big_number_grammar > , proto::negate< big_number_grammar > , proto::modulus<big_number_grammar, big_number_grammar> , proto::shift_left<big_number_grammar, big_number_grammar> , proto::shift_right<big_number_grammar, big_number_grammar>
{};
I assume I could replace
, proto::shift_right<big_number_grammar, big_number_grammar>
with something like:
, proto::shift_right<big_number_grammar, integer_terminal>
Where integer_terminal is a big list of terminal integer types, but is there any way to use a predicate to say "any type that matches predicate X is a terminal"?
Yes. You want: // Match any integral terminal proto::and_< proto::terminal< proto::_ >, proto::if_ < boost::is_integral< proto::_value >() >
HTH, -- Eric Niebler BoostPro Computing http://www.boostpro.com