[ESS] fill-column in Rnw files

[Stephen Eglen]

> If I set the fill-column in an Rnw file to a non-standard value (say
> 100, standard is 70) inside a Latex chunk and I move around and pass
> an R chunk, the fill-column value gets reset.  This looks like a bug
> to me.

How did you change the value of the variable?  Every time you switch
from R to latex, it will re-run e.g. latex-mode, so that any variables
set temporarily will be lost.  If you set it through a hook, you may
have better luck.  e.g. 

  (add-hook 'LaTeX-mode-hook '(lambda() (setq ...)))

as the hooks will be rerun each time you switch mode.

This is a limitation of the current .Rnw setup.

Stephen