Andre Poenitz wrote:
> On Tue, Nov 04, 2003 at 02:00:21PM +0000, Angus Leeming wrote:
>> Andre Poenitz wrote:
>>
>> > On Tue, Nov 04, 2003 at 12:19:25PM +0000, Angus Leeming wrote:
>> >> I have a container that currently allows the user to alter the
>> >> Node container. I want to allow the user to be able to alter the
>> >> Node contents but to not be able to insert, erase Nodes from the
>> >> vector.
>> >>
>> >> What's the best way to proceed?
>>
>> > /// The element list is immutable.
>> > //std::vector<Element> const & elements() const { return
>> > elements_; } Element const & element(size_t i) const {
>> > return elements_[i]; } Element & element(size_t i) {
>> > return elements_[i]; }
>>
>> Actually, it's perfectly safe to provide iterators isn't it, so
>> long as I don't provide access to the storage container itself?
>
> Well... this exposes an implementation detail (type of container) to
> the outer world. Moreover, people are tempted to use ++ on
> iterators, whereas not too many poeple would use (&element(3) + 1)
I don't mind the ++bit. I'm happy with user code:
typedef ElementList<quadratic::Element>::const_element_iterator
const_element_iterator;
const_element_iterator elem_it = elist.begin_elements();
const_element_iterator const elem_end = elist.end_elements();
for (; elem_it != elem_end; ++elem_it)
do_something(*elem_it);
typedef ElementList<quadratic::Element>::node_iterator
node_iterator;
node_iterator node_it = elist.begin_nodes();
node_iterator const node_end = elist.end_nodes();
for (; node_it != node_end; ++node_it)
node_it->set_coord(makeCoord(1.0, 2.0, 3.0));
The important bit is that the user is unable to alter the container
itself (erase, insert).
> So _I_'d prefer the accessor functions.
Yes, I can see why.
However, LyX is trying to use iterators more, not less, and you are
driving that effort. Thay can't be all that bad ;-)
--
Angus
