Runtime constant definitions

[Bill Baxter]

On Fri, Sep 12, 2008 at 3:14 PM, Lars Kyllingstad
<public at kyllingen.nospamnet> wrote:
> Hi,
>
> I'm trying to define a couple of constants that I want to be computed at run
> time. I have written the following code:
>
> ---
>
> /// Square root of real-number precision.
> final real REAL_EPSILON_SQRT;
>
> /// Cube root of real-number precision.
> final real REAL_EPSILON_CBRT;
>
>
> static this()
> {
>    REAL_EPSILON_SQRT = sqrt(real.epsilon);
>    REAL_EPSILON_CBRT = cbrt(real.epsilon);
> }
>
> ---
>
> Compiling this, I get the errors
>
> scid/core.d:21: Error: cannot modify final variable 'REAL_EPSILON_SQRT'
> scid/core.d:22: Error: cannot modify final variable 'REAL_EPSILON_CBRT'
>
> where the lines 21 and 22 are the ones inside the curly braces. What's
> wrong?

D1 or D2?
Does something in the spec lead you to believe that static this()
should get around final's restrictions?

It does seem like there should be some way to make a module-level
constant that requires some computation.

But I'd say just make 'em non final.  Or use CTFE cbrt/sqrt functions.
 Or just precompute the value.

--bb