Fix buffer-local value lookup

Couple of mistakes there:

* buffer-local-value was called too late,
* the symbol wasn't quoted, so buffer-local-value ended up taking a
  peek at fill-column directly, because that's what my/centered-width
  defaults to.

Just wrap the whole thing in with-current-buffer.  That'll make it
easier to introduce new buffer-local variables set via mode hooks.

1 files changed, 15 insertions, 14 deletions

diff --git a/.emacs b/.emacs
index 53f79e1..ed70f21 100644
--- a/.emacs
+++ b/.emacs
@@ -140,20 +140,21 @@
       (set-window-margins win nil))))
 
 (defun my/centered-set-margins (window)
-  (let* ((target-body-width
-          (cond
-           ((symbolp my/centered-width)
-            (buffer-local-value my/centered-width (window-buffer window)))
-           ((integerp my/centered-width)
-            my/centered-width)))
-         (adjustable-width
-          (- (window-total-width window)
-             (+ (fringe-columns 'left) (fringe-columns 'right))))
-         (target-margin
-          (when (> adjustable-width target-body-width)
-            (/ (- adjustable-width target-body-width) 2))))
-    ;; Only set left margin, so that long lines are not truncated.
-    (set-window-margins window target-margin)))
+  (with-current-buffer (window-buffer window)
+    (let* ((target-body-width
+            (cond
+             ((symbolp my/centered-width)
+              (symbol-value my/centered-width))
+             ((integerp my/centered-width)
+              my/centered-width)))
+           (adjustable-width
+            (- (window-total-width window)
+               (+ (fringe-columns 'left) (fringe-columns 'right))))
+           (target-margin
+            (when (> adjustable-width target-body-width)
+              (/ (- adjustable-width target-body-width) 2))))
+      ;; Only set left margin, so that long lines are not truncated.
+      (set-window-margins window target-margin))))
 
 (defun my/kill (stuff)
   (kill-new stuff)