Clarify `paredit-insert-comment' and change its criteria for code comments.

Formerly, this would choose code comments only when code follow the
point on the line.  Now it will insert code comments also when no
code precede the point on the line.  For example, the command will
choose a code comment rather than a margin comment in the following
fragment:

   (foo bar
        |baz
        quux)
=>
   (foo bar
        ;; |
        baz
        quux)

darcs-hash:20081025201840-00fcc-0435e69b7e5e42c43a763dad345c0f8a25925b89

1 files changed, 21 insertions, 28 deletions

diff --git a/paredit.el b/paredit.el
index 6c705a0..73a9d51 100644
--- a/paredit.el
+++ b/paredit.el
@@ -1065,35 +1065,28 @@ This is expected to be called only in `paredit-comment-dwim'; do not
         (code-before-p
          (save-excursion (paredit-skip-whitespace nil (point-at-bol))
                          (not (bolp)))))
-    (if (and (bolp)
-             ;; We have to use EQ 0 here and not ZEROP because ZEROP
-             ;; signals an error if its argument is non-numeric, but
-             ;; CALCULATE-LISP-INDENT may return nil.
-             (eq (let ((indent (calculate-lisp-indent)))
-                   (if (consp indent)
-                       (car indent)
-                     indent))
-                 0))
-        ;; Top-level comment
-        (progn (if code-after-p (save-excursion (newline)))
-               (insert ";;; "))
-      (if code-after-p
-          ;; Code comment
-          (progn (if code-before-p
-                     ;++ Why NEWLINE-AND-INDENT here and not just
-                     ;++ NEWLINE, or PAREDIT-NEWLINE?
-                     (newline-and-indent))
+    (cond ((and (bolp)
+                (let ((indent
+                       (let ((indent (calculate-lisp-indent)))
+                         (if (consp indent) (car indent) indent))))
+                  (and indent (zerop indent))))
+           ;; Top-level comment
+           (if code-after-p (save-excursion (newline)))
+           (insert ";;; "))
+          ((or code-after-p (not code-before-p))
+           ;; Code comment
+           (if code-before-p (newline))
+           (lisp-indent-line)
+           (insert ";; ")
+           (if code-after-p
+               (save-excursion
+                 (newline)
                  (lisp-indent-line)
-                 (insert ";; ")
-                 ;; Move the following code.  (NEWLINE-AND-INDENT will
-                 ;; delete whitespace after the comment, though, so use
-                 ;; NEWLINE & LISP-INDENT-LINE manually here.)
-                 (save-excursion (newline)
-                                 (lisp-indent-line)))
-          ;; Margin comment
-          (progn (indent-to comment-column
-                            1)          ; 1 -> force one leading space
-                 (insert ?\; ))))))
+                 (indent-sexp))))
+          (t
+           ;; Margin comment
+           (indent-to comment-column 1) ; 1 -> force one leading space
+           (insert ?\; )))))
 
 ;;;; Character Deletion