templatizing parameters and induction (was Re: Writing Bug-Free C/D Code)

[David B. Held]

Andrei Alexandrescu (See Website For Email) wrote:
> [...]
> int foo(int x, int y, int z);
> int foo(static int x, int y, int z); // x is known during compilation
> int foo(int x, static int y, int z); // y is known during compilation
> int foo(static int x, static int y, int z); // x and y are... you know
> [...]
> final a = to!(int)(readln), b = to!(int)(readln);
> foo(a, b, b);  // firsts overload
> foo(1, a + b, b); // 2nd
> foo(a + b, a - b, b);  // 3rd
> foo(42, 7, b); // 4th
> [...]

Great sir, could you impart upon us mere mortals the wisdom by which you 
are able to ascertain, at compile time, the difference between two 
values known only at runtime (a la the "3rd" overload)?  We are in great 
need of such Oracle-like behavior.

Dave