General ⇒ A package that allow to put latex source in compiled PDF.

[Hrs]

Hi!

Is there is a package that allow to put latex source in compiled PDF file?
I mean, that package should provide a possibility to do that actions:
1. User compile his TeX file to PDF.
2. User open his PDF file and select some text, for example, with a formula, and copy it.
3. User insert what he copied in the simple word processor (such as notepad), and see the LaTeX source (in our example --- formula's source).