On Thursday, 28 February 2013 at 16:36:44 UTC, Walter Bright
wrote:
On 2/28/2013 6:48 AM, Ary Borenszweig wrote:
On 2/28/13 1:57 AM, Walter Bright wrote:
On 2/27/2013 8:01 PM, John Colvin wrote:
Why must sentinel be known at compile time? I don't see
what's in the
way of it
being a runtime argument.
Performance!
It should be usable as a case in a switch statement.
Isn't it possible for the optimizer to inline the function
call and then combine
the next ifs?
if (isSentinel(value)) {
} else {
switch(value) {
case ...
}
}
1. I don't know of any C compiler that would do that.
As mentioned, LLVM is able to do this kind of things. I have to
admit I was quite amazed when I discovered it.
2. There are other cases, as I pointed out to deadalnix.
3. You still can't do lookahead without extra checks
You need the actual check to do proper generic D code. But the
compiler is able to optimize it away via inlining and mecanism
described in 1.
Once again, guys, have a look at lexer.c at the lines I pointed
out.
I see nothing that can't be done by an optimizing compiler. Maybe
something is, but I can't find it. And the example you pointed me
aren't.
