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From: Larry Evans (cppljevans_at_[hidden])
Date: 2008-03-20 20:04:23


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?


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