On 10/12/13 06:33, Jonathan M Davis wrote:
It's still essentially a singleton - it's just that it's a single instance per
thread in that case instead of per program. And you avoid all of the
threading-related initialization issues with singletons if it's thread-local.
Just check whether it's null, initialize it if it is (leave it alone if it
isn't), and then do whatever you're going to do with it.
So for example the below code as an rndGen where Random is a class, not a
struct?
I think I was misled by the "Only const or immutable ..." part of the error
message: I'd assumed that any class that actually modified its internal state
would be disallowed as a static instance.
///////////////////////////////////////////////////////////////////////////////
ref Random rndGen() @property
{
static Random result = null;
if (result is null)
{
result = new Random;
static if (isSeedable!(Random, typeof(repeat(0).map!((a) =>
unpredictableSeed))))
{
result.seed(repeat(0).map!((a) => unpredictableSeed));
}
else
{
result.seed(unpredictableSeed);
}
}
return result;
}
///////////////////////////////////////////////////////////////////////////////
