Re: header-line-format hacking

[ytrewq1]

Stefan Monnier writes:

> There are currently few uses of the header-line, and most of them seem to be
> "global".  I.e. either it's absent, or its content does not naturally lend
> itself to being accompanied with some other info.
> 
> Could you give a couple examples of the kind of things you'd like to put/add
> into the header-line?

I'm writing a couple of minor modes in which I'd like to express certain
'state' information and I'm not finding a whole lot of space in the
mode line on my system.

One minor mode attempts to display the current 'class' that point is in -- 
similar to what which-function-mode does for functions [1].  On my system, 
there doesn't seem to be enough space to display this in the mode line --
especially when which-function-mode is active.

The other mode is for creating navigable annotated 'traces' through source 
code.  Roughly, a reader of some source code is provided with a way of 
keeping notes as the flow of execution is traced.  At the moment this 
happens by selecting regions of text, indicating that a selected region 
is a call or a definition, and optionally associating some text.  The 
created 'traces' may be navigated (e.g. move to root of trace, move to 
next annotated point of execution, etc.), edited, and shared.

Anyway, I'd like to express the idea of 'trace has been modified' in a way 
similar to what's currently done for 'buffer has been modified'.  I'm also 
thinking of expressing some other trace-related state information but I 
wanted to see if I was able to work with header-line-format appropriately 
before exploring the idea further.

Needless to say, I'd like to use both of these modes at the same time --
which is what prompted my question.


[1] In fact, which-class.el is essentially a modified which-func.el.