Re: [Boost-users] [Proto]: How to use complex grammars in a domain/extension

21 Sep 2010


      On 9/21/2010 4:11 AM, Roland Bock wrote:
...
On 09/21/2010 09:49 AM, Joel Falcou wrote:
...
The following code works here:
//
-----------------------------------------------------------------------
[...]
Yes, I know, but that is not the grammar I need. I want to combine my
terminal similar to std::string, so that:
std::string a, b;
a; // ok
a + b; // ok
a == b; // ok
a == b + b; // ok
a && a == b; // ERROR
...
Seems proto::or_ wiht *1* condition acts weird.
Eric, am I right or am I hallucinating and missing the obvious ?
You can remove the proto::or_ like
struct equation:
      proto::equal_to
{};
It does not change the result. So it does not look like a problem in
proto::or_, but maybe a bug in how proto determines the operators of
extensions?
struct equation:
    proto::or_<
        proto::equal_to,
        proto::terminalproto::_
    >
{};

?

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com