Shipout line like Shipout page

Question

In lineno package guide, I found:

Attaching line numbers after TeX has broken the paragraph into lines is already quite a difficult job for TeX. Why? Because TeX does not normally give you any control after line breaking. lineno.sty does it by pretending that the current page ends after each and every line. This keeps TeX quite busy, but works.

I know the package everyshi which offers \EveryShipout, \AtNextShipout and \AtBeginDocument.

Is there a package that provides \EveryShipoutLine, \AtNextShipoutLine and \AtBeginParagrapheLine?

Otherwise, I have to improve my knowledge of TeX and dissect the lineno package.

Addition, an example of usage :

Answer 1

LuaTeX provides callbacks from which the lines of a paragraph (and paragraphs themselves among other things) can be intercepted and manipulated. I'm just fiddling around with this myself, here are some resources that I found useful (in order):

1. LuaTeX: What it takes to make a paragraph-Isambert
2. The chickenize package
3. Three things you can do with LuaTeX that would be extremely painful otherwise-Isambert

The chickenize package is more of an instructional tool than anything else, it describes how to use callbacks and implements all sorts of strange things with them. On this site, searching for post_linebreak_filter etc. will give you some further examples.