Use syntax-ppss to find the outer sexp

beginning-of-defun just uses open-paren-in-column-0-is-defun-start,
which fooled functions like face-attribute where the docstring
contains a open paren at the start of the line.

Fixes #170

2 files changed, 6 insertions, 3 deletions

diff --git a/helpful.el b/helpful.el
index 8886285..c320cff 100644
--- a/helpful.el
+++ b/helpful.el
@@ -1411,9 +1411,10 @@ along with its position.
 Moves point in BUF."
   (with-current-buffer buf
     (goto-char pos)
-    (let* ((ppss (syntax-ppss)))
-      (unless (zerop (syntax-ppss-depth ppss))
-        (beginning-of-defun)))
+    (let* ((ppss (syntax-ppss))
+           (outer-sexp-posns (nth 9 ppss)))
+      (when outer-sexp-posns
+        (goto-char (car outer-sexp-posns))))
     (list (point) (-take 2 (read buf)))))
 
 (defun helpful--count-values (items)
diff --git a/test/helpful-unit-test.el b/test/helpful-unit-test.el
index f6d4048..dc8acdc 100644
--- a/test/helpful-unit-test.el
+++ b/test/helpful-unit-test.el
@@ -134,6 +134,8 @@ symbol (not a form)."
   (should (helpful--primitive-p 'rename-buffer t)))
 
 (ert-deftest helpful-callable ()
+  ;; Functions. Also a regression test for #170.
+  (helpful-callable 'face-attribute)
   ;; We should not crash when looking at macros.
   (helpful-callable 'when)
   ;; Special forms should work too.