On 20.07.2010 0:05, Philippe Sigaud wrote:
On Mon, Jul 19, 2010 at 21:23, Andrei Alexandrescu
<seewebsiteforem...@erdani.org <mailto:seewebsiteforem...@erdani.org>>
wrote:
What I personally would like is a way to find an element in an
ordered
container (binary tree...)
Wouldn't that be a member of the binary tree?
Yes, indeed. Unless I define some cousin to range, a recursive range,
to iterate on any recursive container, like trees or graphs and then
devise algorithms on them. I played with this idea a few weeks ago but
went to do other things. Anyway, carry on.
Btw, I still plan to update some simple generic graphs and trees
structs to obey TotalContainer interface when it makes sense, and
update my graph algorithms accordingly. If I ever get somewhere, I'll
post something.
Aren't such scenarios better served by putting the limits
inside the
predicate? Otherwise the list of what can be done could go
on forever.
The problem is that, as the predicate is passed at
compile-time, the
limits must be CT-defined too. I'd like the limits to be
defined at
runtime. I run into this regularly, while using predicates in
std.algorithms.
I think this is a misunderstanding. All of std.algorithm works
with delegates:
int[] a = [ 1, 4, 2, 3 ];
int b = 2;
assert(find!((x) { return x > b; })(a) == [4, 2, 3]);
Ah yes, but I regularly use algorithms structs as return values, like
this:
auto nTimes(E, R)(E multiplier, R range)
{
return map!((ElementType!R e) { return e*multiplier;})(range);
}
Try this workaround, replacing delegate with nested function, works for me:
auto nTimes(E, R)(E multiplier, R range){
ElementType!R fun(ElementType!R e) { return e*multiplier; }
return map!(fun)(range);
}
For some reason, compiler never plays nice with map, and I believe there
are some issues with current implementation (2.047 release ) that Andrei
(hopefully) fixed in recent commit.
Philippe
--
Dmitry Olshansky
