Re: [drew.adams@oracle.com: links in Help buffer aren'talwayscorrect]

[Kevin Rodgers <ihs_4664@yahoo.com>]

Drew Adams wrote:
>     describe-frame-parameter seems to work usefully, but it has one
>     problem: its completion list is incomplete.
> 
> Do you mean because it iterates only over the parameters of the selected
> frame?
> 
> It might also include user-defined parameters that won't be documented in
> Info. Perhaps it should instead iterate over an explicit list of all of the
> Info-documented (built-in) frame parameters.

I'm sure that's what he means.  But by analogy, `M-x describe-variable'
doesn't complete on void symbols, and it is well understood that an
unset frame parameter's value is effectively void: frame-parameter
actually returns nil, but it means the parameter has no effect.

So why provide completion on all documented frame parameters?  So that
the user can simply type ? at the prompt to see the entire list of frame
parameters.  That would be really useful, if there was also a
set-frame-parameter command.

And if there were a define-frame-parameter function and/or defframeparam
macro that would maintain a global list (or obarray) of frame
parameters, it would allow `M-x describe-frame-parameter' and `M-x
set-frame-parameter' to reliably complete over both documented and
user-defined frame parameters.

> Perhaps too, the doc string should mention that it only works on documented
> built-in frame parameters, not user-defined parameters.

That seems like the right thing to do, unless we define a global
list (or obarray) of frame parameters to complete over.

> I noticed too that in emacs -q, M-x describe-frame-parameter RET
> cursor-color gives an error because Info-find-node is not defined
> (autoloaded).

Good point.  I think that since Info-goto-node displays the *Info*
buffer, it should be declared as an (interactive) command, and
therefore that it should be autoloaded.

-- 
Kevin Rodgers