Steven Schveighoffer wrote:
On Sun, 07 Mar 2010 12:43:09 -0500, Robert Jacques <[email protected]>
wrote:
On Sun, 07 Mar 2010 08:23:03 -0500, Steven Schveighoffer
<[email protected]> wrote:
What is the advantage? Why would an algorithm require soft
functions? What is an example of such an algorithm?
Something that uses toUpperCase or toLowerCase, for example.
I guess I won't get a real example. I'm not sure it matters. When
Andrei starts implementing the soft methods, either they will be a huge
win or obviously useless. If I were a betting man, I'd bet on the
latter, but I'm not really good at betting, and Andrei's ideas are
usually good :)
The way people usually take advantage of non-invalidating container
primitives is altering the container during an iteration. The canonical
way to remove while iterating an erase-non-invalidating container (e.g.
map) is this:
typedef ... Container;
Container c;
for (Container::iterator i = c.begin(); i != c.end(); )
{
if (should_delete_this_guy)
c.remove(i++);
else
++i;
}
The canonical way to remove while iterating an erase-invalidating
container (e.g. vector) is:
typedef ... Container;
Container c;
for (Container::iterator i = c.begin(); i != c.end(); )
{
if (should_delete_this_guy)
i = c.remove(i);
else
++i;
}
I know, subtle :o/. Of course, things can get quickly more interesting
when calling functions from within loops that may affect the container
(think the Observer pattern).
Andrei
