On Wed, 26 Mar 2014 16:38:57 -0000, monarch_dodra <[email protected]>
wrote:
On Wednesday, 26 March 2014 at 15:37:38 UTC, Steven Schveighoffer wrote:
Yes, but when you know that empty is going to return false, there isn't
any logical reason to call it. It is an awkward requirement.
-Steve
Not only that, but it's also a performance criteria: If you are
iterating on two ranges at once (think "copy"), then you *know* "range2"
is longer than "range1", even if you don't know its length.
What guarantees range2 is longer than range1? The isArray case checks
explicitly, but the generic one doesn't. Is it a property of being an
output range that it will expand as required, or..
Why pay for "range2.empty", when you know it'll always be false? There
is a noticeable performance difference if you *don't* check.
But aren't you instead paying for 2 checks in front and 2 in popFront, so
4 checks vs 1? Or is the argument that these 4 checks cannot be removed
even if we mandate r.empty is called before r.front/popFront.
R
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