I thought I understood ranges until I actually started trying to use
them. Now I'm having difficulties with the new range-based containers.
So I've got two issues right now, grokking ranges and understanding the
container interfaces.
Given an SList, I want to do the following:
foreach(obj; list)
{
if(obj.pleaseKillMe)
somehow_remove_the_object_from_the_list();
}
Part of my problem is I'm not entirely clear what's going on with the
foreach. I know it's iterating a range, but is it the SList itself being
iterated, or is it a range returned by SList.opSlice? I assume the
latter, which at one point led me to try this (thinking of Java's
iterator.remove()):
auto r = list[];
foreach(obj; r)
{
if(obj.pleaseKillMe)
r.popFront();
}
Which, of course, didn't work. I see that popFront doesn't actually
'pop' anything off of, or out of, the range as it would in a traditional
stack or a queue. The foreach doc says about range.popFront:
move the left edge of the range right one
Meaning, it's more like a next() than the pop() I'm familiar with
(recalibrating all those years of C and Java terminology is not easy).
And even if it did, changes to the range do not propagate to the
underlying container. I understand that, at least (now).
So apparently I want something like the list.stableRemove*() variants,
which the docs say remove an item from a container without invalidating
any ranges currently iterating the container. Great! Only, there's no
variant that accepts a single item. SList has removeFront and removeAny,
and ranges can be removed via linearRemove. I can insert individual
items fine. But how do I remove them?
