21 Mar
2008
21 Mar
'08
12:04 a.m.
On 03/20/08 18:10, Eric Niebler wrote:
Larry Evans wrote:
I don't think it solves any problem that can't already be solved, but it makes the solution clearer. It's clearer because the arity is associated with the tag *not* the expression. The arity of a tag does not depend on the expression; so, it should not be in the expression. Instead the arity of the tag determines the expression validity.
Sorry, but that's backwards. Tags don't have arities, expressions do. The arity of tag::function could be anything. The arity represents the number of children of an expression node. So the arity is a very real part of an expression.
So: expr<tag::shift_right, Args, 20> is a valid expression?