Would a declarative parsing method be convenient?

Question

Parsing

It would be convenient for someone to use a tool with which one could, for example, parse certain pages from habr, including internal content, using the following input data:

{
  "__url__": "'http://habrahabr.ru/page{{1,1,5}}/'",
  "posts": {
    "__iterator__": ".post",
    "name": "{{.post_title}}",
    "content": {
      "__follow__": "{{.post_title | first | attr_href}}",
      "post_body": "{{.content}}",
      "author": "{{.author > a}}",
      "comments": "{{#comments}}"
    }
  }
}

And at the output, get something like: pastie.org/9799295
I was looking for similar tools, I did not find it. The closest in meaning is, as I understand it, XSLT templates.
And is everything obvious in the input parameters? css\xpath selectors, paging, applying filters to the result.
If it really seems useful, please write, it will speed up the launch of the gem, writing the documentation and launching the test service

Answer 1

The coolest automatic page access syntax would be sql-like.

Answer 2

Many sites generate a lot of things using js.
If your gem analyzes not stupidly the source code of the page, but climbs a completely generated house-tree, it will be very cool.