On 03/22/08 09:13, Steven Watanabe wrote:
AMDG
Larry Evans wrote:
On 03/22/08 06:12, Dean Michael Berris wrote: [snip]
I think this begs the question then, what is the necessity for an Arity parameter as part of the definition of an expr<>? [snip] it's use for specialization. In my reply to that post I suggested maybe a helper template to eliminate the need for this 3ird parameter, but then, AFAICT, this just delays the need for a 3 parameter expr...but wait, if some how the 2 parameter expr were public and somehow the 3 parameter were made private, maybe that would be better.
Well, since expr is an aggregate, adding an extra layer of indirection would change the interface, so I don't think that would work.
Hi Steven, Could you post a test case with the before (only 1 expr with 3 args) and after (i.e. 2 expr templates where proto::expr takes 2 args and proto::detail::expr takes 3 args, where the 3ird is the arity) and then maybe some example in proto which specializes on arity and show how the 2 expr template method wouldn't work? Of course I could try it and see if I could make it fail, but I was hoping you had a better idea of how to make it ( i.e. the 2 expr method) fail. -regards, Larry