On Thu, 04 Apr 2013 15:10:28 -0400, Walter Bright
<newshou...@digitalmars.com> wrote:
On 4/2/2013 8:10 PM, Steven Schveighoffer wrote:
On Tue, 02 Apr 2013 16:32:21 -0400, Walter Bright
<newshou...@digitalmars.com>
wrote:
For example, with a signed array index, a bounds check is two
comparisons
rather than one.
Why?
struct myArr
{
int length;
int opIndex(int idx) { if(cast(uint)idx >= cast(uint)length) throw
new
RangeError(); ...}
}
Being able to cast to unsigned implies that the unsigned types exist. So
no improvement.
The issue is the type of length, not that uints exist. In fact, opIndex
can take a uint, and then you don't need any casts, as far as I know:
int opIndex(uint idx) { if(idx >= length) throw new RangeError(); ...}
I think length will be promoted to uint (and it is always positive), so
it's fine, only requires one check.
-Steve
