On Sunday, 11 November 2012 at 13:40:45 UTC, evansl wrote:
On 11/11/12 06:49, Peter Alexander wrote:
On Sunday, 11 November 2012 at 12:33:25 UTC, Manfred Nowak
wrote:
a) Instantiability is decidable
Why does the compiler stop with the evaluation at that
randomly
choosen and apparently hard coded value of 500 recursive
expansions?
It's not decidable. Consider use of static if. It's Turing
complete. I
can give an example if you like.
I'd like. An example might help me better understand why it's
undecidable.
[snip]
Collatz sequence.
struct Collatz(int n)
{
enum next = n % 2 == 0 ? n / 2 : 3 * n + 1;
Collatz!(next)* foo;
}
It's an unsolved problem in mathematics whether or not this
instantiates an infinite number of templates.
