[OS X Emacs] How to get truncated lines in a particular mode?

[Marius Hofert]

Dear all,

I have (global-visual-line-mode 1) in Preferences.el to get the "word-wrap" behavior by default. For working with .R files, I would like to have truncated lines. I tried:

(add-hook 'ess-mode-hook
          (lambda ()
            ... ; other commands affecting this mode
            (visual-line-mode 0)
	    )
	  )

That didn't change the word-wrap behavior in .R files. How is it done correctly?

Another question: Is "M-x visual-line-mode" the correct command to toggle the behavior (word-wrap/truncated) "locally"?

Cheers,

Marius