Introduce get_multipage_link()

[scribu]

There currently is no function for retrieving the URL to a multipage part (a page with <!--nextpage-->).

The code is burried in a private helper function.

Let's bring it to light.

[ldebrouwer]

It might be better to put $output on one line instead of concatenating another line to it on three occasions. Maybe even sprintf'ing it would be an even more elegant solution.

[scribu]

clearer logic

[scribu]

16973.3.diff​ does some cleanup in wp_link_pages() and also removes the @private comment, since it's clearly used in the wild.

[scribu]

more cleanup

[kobenland]

Patch ​16973.4.patch makes links and output filterable, as suggested in #13578.

[mdgl]

This would be useful, as would further helper functions for themes/plugins dealing with multipage posts (see #16468 for some ideas from nacin).

[DrewAPicture]

No activity in two years, and the patch is out of date. @obenland: Care to revisit here?

[obenland]

I don't feel particularly strong about it either way.

Paged posts is a very little used feature, and given the fact that this ticket hasn't seen any meaningful action in four years, it can probably be closed.
If paged posts get a UI and it gets more popular, we can still revisit it.