Emacs Set Window to 80 Columns

When I'm coding, I maximize Emacs and enable winner-mode, turning my display into something much like a tiling window manager. Then I try not to leave Emacs until it's necessary. It's a really nice way to work: no mouse touching needed.

At work they gave me a nice 24" monitor, 1920 pixels across. That's just about enough to fit three Emacs' windows side-by-side at 78 columns each. The leftmost one contains my active work buffer where I do most of my typing. The center one is usually split horizontally. The top half is the *compilation* buffer and the bottom half is either Emacs calculator or an *ansi-term* buffer. The rightmost buffer contains something more static, like some sort of reference material.

However, I like my main editing window to be 80 columns wide. 78 columns cuts just too short. For awhile I was creating 80 dashes (C-u 80 -) and adjusting the window width manually to size. After doing it a few times I decided to extend Emacs to do it instead. First define a function to set the current window width.

(defun set-window-width (n)
  "Set the selected window's width."
  (adjust-window-trailing-edge (selected-window) (- n (window-width)) t))

Wrap it with an interactive function and bind it.

(defun set-80-columns ()
  "Set the selected window to 80 columns."
  (set-window-width 80))

(global-set-key "\C-x~" 'set-80-columns)

For those paying extra attention: instead of writing the extra function, you could use my expose function from the other day.

(global-set-key "\C-x~" (expose (apply-partially 'set-window-width 80)))

The problem with this, though, is the dynamically generated function doesn't have a name or a docstring. Someone using describe-key would have little information to go on.

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Chris Wellons