letf and setf are okay as work-arounds, I suppose.

The package I use these for is
http://github.com/nex3/perspective-el/blob/master/perspective.el. Each frame
keeps track of a separate set of workspaces, as well as various other useful
variables (the current workspace, previous workspace, etc.).

On Tue, May 18, 2010 at 8:29 AM, Stefan Monnier <monnier@iro.umontreal.ca>wrote:

> > But frame-parameters have to be manually managed with frame-parameter,
> no?
>
> Sounds obvious, doesn't it?
>
> > Even ignoring compatibility for user-facing configuration, it seems
> really
> > annoying to have to call frame-parameter and set-frame-parameter all the
> > time, especially if you're trying to simulate `let'.
>
> No, it really doesn't seem particularly annoying:
>
>   (require 'cl)
>   (letf (((frame-parameter <foo>) 'newvalue)) <blabla>)
>
> the same holds for symbol properties, process properties, window
> parameters, terminal parameters, ...
>
> > Are there at least any plans for a nicer API for working with what used
> to
> > be frame-local variables?
>
> BTW, since frame-parameters have been very rarely used and you seem to
> use them "extensively", I'm curious: what do you use them for
> (i.e. what kind of data do you keep there, and why do you need to
> let-(re)bind it)?
>
>
>        Stefan
>