Hi Boris, Boris Kolpackov wrote:
Hi Stefan,
Stefan Seefeld <seefeld@sympatico.ca> writes:
What about an interface similar to SAX, where the user provides a set of handlers, one per type, and then the reader calls the appropriate one ? For example:
void handle1(token1 const &); void handle2(token2 const &); ...
typedef reader<handle1, handle2, ...> my_reader; my_reader r(filename); while (r.next()) r.process();
I think there is not much you can do in that while loop except calling process() which then brings the question of why not use the push model (e.g., SAX) since that is what you are essentially emulating.
Are you arguing against the pull model here or against my use of callbacks ?
Also note that you can get this behavior with a normal reader and a visitor but with a modular design as a bonus:
typedef visitor<handle1, handle2, ...> v; reader r (filename); while (node* n = r.next()) v.visit (n);
That's right, but that is inefficient: The reader already does know the type of the token, but in the name of 'modular design' you throw it away only to recover it later with an extra round-robin dispatch through the visitor. What is the advantage of that ? Regards, Stefan -- ...ich hab' noch einen Koffer in Berlin...