Compile time function execution...

[Michiel]

Frits van Bommel wrote:

>> * Why is the second sqrt(10) run at runtime? In theory it's still a
>> constant, right? Is this something that will work in a later version?
> 
> From the spec:
> """
> In order to be executed at compile time, the function must appear in a
> context where it must be so executed, for example:
> 
>     * initialization of a static variable
>     * dimension of a static array
>     * argument for a template value parameter
> """
> 
> So this is only done if it's used in a context where only compile-time
> constants are allowed.

Well, then there is room for improvement. (Good thing, too. Can you
imagine how bad it would be if perfection had already been achieved? ;))

Anyway, it looks to me like every subtree of the abstract syntax tree
could potentially be collapsed by compile time function execution. This
would include the mentioned sqrt call. Of course, I don't really know
how the D compiler works internally, so I can't be sure in this case.

And I don't see a real reason why structs and at least scope classes
couldn't be included. But I don't suppose it's all that easy.

Maybe the perfect compiler would also pre-execute everything up until
the first input is needed. And maybe some bits after.

-- 
Michiel