* simple.el (next-error-find-buffer): Move the rule

"if current buffer is a next-error capable buffer" after the
rule "if next-error-last-buffer is set to a live buffer".
Simplify to test all rules in one `or'.
(next-error): Doc fix.

diff --git a/lisp/simple.el b/lisp/simple.el
index 32eecec8d4b9263529c9eef031d64e62c224867e..2b21967a0008decbbf5f63b9d375cbdd3401c092 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -91,49 +91,48 @@ to navigate in it.")
     (or (and extra-test (funcall extra-test))
        next-error-function)))
 
-;; Return a next-error capable buffer according to the following rules:
-;; 1. If the current buffer is a next-error capable buffer, return it.
-;; 2. If one window on the selected frame displays such buffer, return it.
-;; 3. If next-error-last-buffer is set to a live buffer, use that.
-;; 4. Otherwise, look for a next-error capable buffer in a buffer list.
-;; 5. Signal an error if there are none.
 (defun next-error-find-buffer (&optional other-buffer extra-test)
-  (if (and (not other-buffer)
-          (next-error-buffer-p (current-buffer) extra-test))
-      ;; The current buffer is a next-error capable buffer.
-      (current-buffer)
-    (or
-     (let ((window-buffers
-            (delete-dups
-             (delq nil
-              (mapcar (lambda (w)
-                        (and (next-error-buffer-p (window-buffer w) extra-test)
-                             (window-buffer w)))
-                      (window-list))))))
-       (if other-buffer
-           (setq window-buffers (delq (current-buffer) window-buffers)))
-       (if (eq (length window-buffers) 1)
-           (car window-buffers)))
-     (if (and next-error-last-buffer (buffer-name next-error-last-buffer)
-              (next-error-buffer-p next-error-last-buffer extra-test)
-              (or (not other-buffer) (not (eq next-error-last-buffer
-                                              (current-buffer)))))
-         next-error-last-buffer
-       (let ((buffers (buffer-list)))
-         (while (and buffers (or (not (next-error-buffer-p (car buffers) extra-test))
-                                 (and other-buffer
-                                      (eq (car buffers) (current-buffer)))))
-           (setq buffers (cdr buffers)))
-         (if buffers
-             (car buffers)
-           (or (and other-buffer
-                    (next-error-buffer-p (current-buffer) extra-test)
-                    ;; The current buffer is a next-error capable buffer.
-                    (progn
-                      (if other-buffer
-                          (message "This is the only next-error capable buffer."))
-                      (current-buffer)))
-               (error "No next-error capable buffer found"))))))))
+  "Return a next-error capable buffer."
+  (or
+   ;; 1. If one window on the selected frame displays such buffer, return it.
+   (let ((window-buffers
+          (delete-dups
+           (delq nil (mapcar (lambda (w)
+                               (if (next-error-buffer-p
+                                    (window-buffer w) extra-test)
+                                   (window-buffer w)))
+                             (window-list))))))
+     (if other-buffer
+         (setq window-buffers (delq (current-buffer) window-buffers)))
+     (if (eq (length window-buffers) 1)
+         (car window-buffers)))
+   ;; 2. If next-error-last-buffer is set to a live buffer, use that.
+   (if (and next-error-last-buffer
+            (buffer-name next-error-last-buffer)
+            (next-error-buffer-p next-error-last-buffer extra-test)
+            (or (not other-buffer)
+                (not (eq next-error-last-buffer (current-buffer)))))
+       next-error-last-buffer)
+   ;; 3. If the current buffer is a next-error capable buffer, return it.
+   (if (and (not other-buffer)
+            (next-error-buffer-p (current-buffer) extra-test))
+       (current-buffer))
+   ;; 4. Look for a next-error capable buffer in a buffer list.
+   (let ((buffers (buffer-list)))
+     (while (and buffers
+                 (or (not (next-error-buffer-p (car buffers) extra-test))
+                     (and other-buffer (eq (car buffers) (current-buffer)))))
+       (setq buffers (cdr buffers)))
+     (if buffers
+         (car buffers)
+       (or (and other-buffer
+                (next-error-buffer-p (current-buffer) extra-test)
+                ;; The current buffer is a next-error capable buffer.
+                (progn
+                  (if other-buffer
+                      (message "This is the only next-error capable buffer"))
+                  (current-buffer)))
+           (error "No next-error capable buffer found"))))))
 
 (defun next-error (&optional arg reset)
   "Visit next next-error message and corresponding source code.
@@ -153,9 +152,10 @@ compilation, grep, or occur buffer.  It can also operate on any
 buffer with output from the \\[compile], \\[grep] commands, or,
 more generally, on any buffer in Compilation mode or with
 Compilation Minor mode enabled, or any buffer in which
-`next-error-function' is bound to an appropriate
-function.  To specify use of a particular buffer for error
-messages, type \\[next-error] in that buffer.
+`next-error-function' is bound to an appropriate function.
+To specify use of a particular buffer for error messages, type
+\\[next-error] in that buffer when it is the only one displayed
+in the current frame.
 
 Once \\[next-error] has chosen the buffer for error messages,
 it stays with that buffer until you use it in some other buffer which