Specializing on Compile Time Constants

[dsimcha]

== Quote from Jacob Carlborg (doob at me.com)'s article
> On 10/12/09 23:49, dsimcha wrote:
> > I'm working on a mathematical expression interpreter for D, which would allow
> > for closed form mathematical expressions to be specified as string literals at
> > runtime and be evaluated.  For example:
> >
> > MathExp myExpression = mathExp("x^2 + e^cos(-x) - 2 * sqrt(pi)", "x");
> > writeln(myExpression(2));  // Does exactly what you think it does.
> >
> > I've found the syntax so convenient that I'd like to transparently specialize
> > it on strings known at compile time.  The idea is that, when the expression is
> > hard-coded, you will still be able to use the MathExp interface, but your
> > expression will evaluate at the full speed of a statically compiled function.
> >   Is there any way to test whether the value of an argument to a template
> > function is known at compile time and specialize on this?
> Doesn't all values to a template have to be known at compile time

No, I mean the *function* parameters of a template function.