Hacker News Reader

Comment by TreeRingCounter | Hacker News Reader

Can someone summarize this? 90% of the content on this page seems like excessively-verbose nonsense.

Many, if not most, computer models represent data as a tree. Some data, however, can't really be represented by a tree, because a "thing" can have multiple parents.

The example in the link:

Example, with lines marked up:

  <line>I, by attorney, bless thee from thy mother,</line>

  <line>Who prays continually for Richmond's good.</line>

  <line>So much for that.—The silent hours steal on,</line>

  <line>And flaky darkness breaks within the east.</line>

With sentences marked up:

  <sentence>I, by attorney, bless thee from thy mother,
  Who prays continually for Richmond's good.</sentence>

  <sentence>So much for that.</sentence>

  <sentence>—The silent hours steal on, And flaky darkness breaks within the east.</sentence>

If you care about lines and sentences, this is difficult to represent as a tree.

One way to solve this could be to provide separate start/end tags without inner content.

  <line-start/><sentence-start/>I, by attorney, bless thee from thy mother,<line-end/>
  <line-start/>Who prays continually for Richmond's good.<sentence-end/><line-end/>

Yeah, that's how the linked article does it, but that's ... icky? It's still a token spanning multiple parents, it's just masquerading as a couple of self-closing tags.

Which, of course, is the point of the article, and why this is a difficult problem.

Ah you're right, I should have read the article before commenting, haha. I agree it's not an ideal solution. A disadvantage I imagine is that this syntax pushes the problem onto the parser/consumer to keep track of overlapping regions.

> Milestones are empty elements that mark the beginning and end of a component, typically using the XML ID mechanism to indicate which "begin" element goes with which "end" element.

https://en.wikipedia.org/wiki/Overlapping_markup#Milestones

Perfect, thanks.

Reply on news.ycombinator.com