FWIW, the following two minor modes are already part of  Emacs:

* which-function-mode
* semantic-stickyfunc-mode

On Mon, Oct 31, 2016 at 3:30 PM, Richard Copley <rcopley@gmail.com> wrote:

> On 27 October 2016 at 13:51, Alain Schneble <a.s@realize.ch> wrote:
> > Alain Schneble <a.s@realize.ch> writes:
> >
> >> Below you will find a patch to extend show-paren-mode with a new
> >> `prelude' style.  It's an extension of `parenthesis' style.  If the
> >> matching opening paren is not visible, it will show the line of text
> >> containing it as an overlay on the window's start line.  I think it's
> >> pretty useful, as it helps in keeping context when working e.g. in
> >> defuns with many lines of code -- all without having to scroll up and
> >> down.
> >
> > It just came to my mind that I might better had introduced a new
> > separate customizable option to enable or disable prelude instead of
> > mixing it with the already existing style.  After all, it could be
> > useful in *addition* to the existing ones.  What do you think?
>
> Alain,
> I agree, it seems to be orthogonal to show-paren mode. It sounds
> more like a good old-fashioned minor-mode than a custom option.
>
> Did you rule out using header-line-format? My feeling is that
> as a user I want to see the line at window-start and I'd prefer
> it not to be obscured by an overlay.
>
>