Trouble creating a formatted assert wrapper

[Peter Alexander]

On Monday, 3 September 2012 at 09:15:08 UTC, Chris 
Nicholson-Sauls wrote:
> On Sunday, 2 September 2012 at 23:40:01 UTC, Peter Alexander 
> wrote:
>>
>> Consider:
>>
>> myAssert(false, "%d", 1);
>>
>> What is Args? "%d", 1 could refer to the optional arguments, 
>> or the variadic arguments. Both match.
>
> Easy: the variadic arguments are not, themselves, optional.  
> Match the variadic.  This kind of problem is already solved in 
> every language with "scattering" assignments, and other such 
> features.

The variadic arguments are optional, as you can have zero 
arguments count as variadic.

Also, how can I override the optional arguments in this function 
if all arguments are matched as variadic?