Static argument optimization

[Don]

Janderson wrote:
> Vladimir Panteleev wrote:
>> Hello,
>>
>> Often I encounter cases where I have a function taking some arguments, 
>> and I'd like for the compiler to generate separate code for the 
>> function when some of the arguments are known at compile time. For 
>> example, consider this function:
>>
>> int pow(int n, int power)
>> {
>>     return power==0 ? 1 : n*pow(n, power-1);
>> }
>>
>> I am looking for a way to make the function work at runtime, while 
>> pow(n, 3) to be inlined as n*n*n, and pow(2, 3) to be precalculated as 
>> 8. Is it possible to do this with some template trickery without 
>> having to write three versions of the function? I know macros should 
>> be able to do this in theory...
>>
> 
> Walter has talked about adding the keyword static in the past to 
> generate templates ie:
> 
> int pow(static int n, static int power)
> {
> 
> }
> 
> I'm not sure if all the params needed to be constant for it to generate 
> a template.  I can't see why your proposal wouldn't work with this.
> 
> -Joel

No, they don't all need to be constant. The classic example is a regexp, 
where the regexp itself is a literal, but the other parameters are all 
variables.