On 8/4/17 8:49 AM, Q. Schroll wrote:
One can do
BigInt n = returnsBigInt();
foreach (i; BigInt(0) .. n)
{ .. }
How is this implemented? The code for BigInt is very large and I didn't
find it.
And is it more efficient than
for (BigInt i = 0; i < n; ++i)
{ .. }
Any foreach range statement like this:
foreach(var; A .. B)
is treated as if you wrote:
for(auto var = A; var < B; ++var)
So it's pretty much exactly like what you wrote, just the initializer is
different but the result is the same.
> as incrementing is a costly operation?
Here is increment in bigint:
https://github.com/dlang/phobos/blob/master/std/bigint.d#L563
And addOrSubInt:
https://github.com/dlang/phobos/blob/master/std/internal/math/biguintcore.d#L508
I think there is room for improvement, as incrementing or decrementing
by 1 is probably something that can be optimized.
-Steve
