Eric Niebler <eric@boost-consulting.com> writes:
BOOST_PROTO_TYPEOF is internal only. I'll rename it, and #undef it at the end of context.hpp.
Ok. Thanks.
Nodes in proto's expression tree are held by reference, so that building an expression tree requires no copying. But some nodes are temporaries. deep_copy() forces all nodes to be held by value, which is necessary if you're storing them in a local variable like this.
Actually, I'm trying to do the opposite: I have expressions used to represent the way to do quantization and manage overflow which have noting to refer to when they're created, so they're made of operators and terminals with no data in. The type is all that is needed for evaluating them, and the evaluation context will know where to grab the data from. Although evaluation is driven by the type, it is a run-time evaluation. I hope to be able to use evaluation contexts for this, if it doesn't work either transforms or an homebrewed solutions (but still using proto for describing the expression). Since you mentioned by-ref/by-value, there's something I meant to ask: proto stores by ref: wouldn't be possible to let the terminal decide? When data is a simple builtin, by-value would be more efficient. I haven't checked the implementation, so I'm not sure the above makes sense. Best regards, Maurizio