bug#9054: 24.0.50; show source in other window

[martin rudalics]

 issues.> For example, ‘C-h f’ (describe-function) first calls a back-end 
function
> that collects all information about a function and returns it in a such form:
>
>    ((type . function)
>     (name . "car")
>     (source-file . "src/data.c")
>     (Info-node . "(elisp) List Elements")
>     (docstring . ...)
>     ...)
>
> Then it gives this data to a front-end function that will render it
> as buttonized text in the Help buffer, or as html in a eww buffer,
> or as Info markup in an Info buffer, etc.

And ‘describe-function-help-front-end’ would peruse that information.
And 'describe-key-help-front-end' would use a 'key' entry.  But what
would you pass to 'view-lossage-help-front-end'?

Anyway I seem to see what you have in mind: Each front end would have
its own rules for how to render the cdr of 'type' or 'name' entries.
And the back end would not be concerned with rendering.

>>> Indeed, now there are such modifiers: ‘C-x 4 0’ and ‘C-x 4 4’.
>>
>> I meant modifiers for mouse-1 clicks on the menu entry.
>
> But ‘C-x 4 0’ and ‘C-x 4 4’ already do what is needed,
> and indeed I tested these work fine: ‘C-x 4 0 down-mouse-3’.

That's not for people who start to explore Emacs via the context menus.
Since you are currently writing them from scratch, they should provide a
simpler interface IMHO.  I'd say C-<mouse-1> should pop up the desired
information in another window, M-<mouse-1> in another frame, ...

martin