[boost] Re: [spirit] rule<> and copying

Joel de Guzman wrote:

Consider:

rule<> a = x;

or:

rule<> a; a = x;

How should this behave if x is an int_p?

The int_p gets stored in an object on the heap, and the rule<> stores a shared_ptr to a polymorphic base.

Now how should it behave if x is another rule? Consider a concrete example (snipped from the pascal parser):

rule<> identifier; rule<> fileIdentifier;

identifier = ....

fileIdentifier = identifier; // an alias

The shared_ptr's reference count goes up. What's the problem? -- Eric Niebler Boost Consulting www.boost-consulting.com