Improve seq-group-by to return sequence elements in correct order

* lisp/emacs-lisp/seq.el (seq-group-by): Improves seq-group-by to
return sequence elements in correct order
* tests/automated/seq-tests.el: Update test for seq-group-by
* doc/lispref/sequences.texi (Sequence Functions): Update documentation
examples for seq-group-by

doc/lispref/ChangeLog

@@ -4,6 +4,11 @@
 	fullscreen frame parameter.  Describe `fullscreen-restore'
 	parameter.
 
+2015-02-09 Nicolas Petton <nicolas@petton.fr>
+
+	* sequences.texi (Sequence Functions): Update documentation
+	examples for seq-group-by.
+
 2015-02-09  Eli Zaretskii  <eliz@gnu.org>
 
 	* positions.texi (Screen Lines): Update the documentation of

doc/lispref/sequences.texi

@@ -731,11 +731,11 @@ of @var{sequence}.  Keys are compared using @code{equal}.
 @example
 @group
 (seq-group-by #'integerp '(1 2.1 3 2 3.2))
-@result{} ((t 2 3 1) (nil 3.2 2.1))
+@result{} ((t 1 3 2) (nil 2.1 3.2))
 @end group
 @group
 (seq-group-by #'car '((a 1) (b 2) (a 3) (c 4)))
-@result{} ((a (a 3) (a 1)) (b (b 2)) (c (c 4)))
+@result{} ((b (b 2)) (a (a 1) (a 3)) (c (c 4)))
 @end group
 @end example
 @end defun

lisp/ChangeLog

@@ -1,3 +1,8 @@
+2015-02-09  Nicolas Petton <nicolas@petton.fr>
+
+	* emacs-lisp/seq.el (seq-group-by): Improves seq-group-by to
+	return sequence elements in correct order.
+
 2015-02-11  Martin Rudalics  <rudalics@gmx.at>
 
 	* frame.el (toggle-frame-maximized, toggle-frame-fullscreen):

lisp/emacs-lisp/seq.el

@@ -4,7 +4,7 @@
 
 ;; Author: Nicolas Petton <nicolas@petton.fr>
 ;; Keywords: sequences
-;; Version: 1.1
+;; Version: 1.1.1
 
 ;; Maintainer: emacs-devel@gnu.org
 
@@ -245,17 +245,16 @@ negative integer or 0, nil is returned."
   "Apply FUNCTION to each element of SEQ.
 Separate the elements of SEQ into an alist using the results as
 keys.  Keys are compared using `equal'."
-  (nreverse
-   (seq-reduce
-    (lambda (acc elt)
-      (let* ((key (funcall function elt))
-             (cell (assoc key acc)))
-        (if cell
-            (setcdr cell (push elt (cdr cell)))
-          (push (list key elt) acc))
-        acc))
-    seq
-    nil)))
+  (seq-reduce
+   (lambda (acc elt)
+     (let* ((key (funcall function elt))
+            (cell (assoc key acc)))
+       (if cell
+           (setcdr cell (push elt (cdr cell)))
+         (push (list key elt) acc))
+       acc))
+   (seq-reverse seq)
+   nil))
 
 (defun seq--drop-list (list n)
   "Return a list from LIST without its first N elements.

test/ChangeLog

@@ -3,6 +3,12 @@
 	* automated/package-test.el (package-test-signed):
 	More informative failure messages.
 
+2015-02-09  Nicolas Petton <nicolas@petton.fr>
+
+	* automated/seq-tests.el (test-seq-group-by): Update test for
+	seq-group-by to check that sequence elements are returned in the
+	correct order.
+
 2015-02-07  Fabián Ezequiel Gallina  <fgallina@gnu.org>
 
 	* automated/python-tests.el (python-eldoc--get-symbol-at-point-1)

test/automated/seq-tests.el

@@ -216,10 +216,10 @@ Evaluate BODY for each created sequence.
   (should (equal (seq-partition '(1 2 3) -1) '())))
 
 (ert-deftest test-seq-group-by ()
-  (should (equal (seq-group-by #'test-sequences-oddp [1 2 3 4])
-                 '((t 3 1) (nil 4 2))))
+  (should (equal (seq-group-by #'test-sequences-oddp '(1 2 3 4))
+                 '((t 1 3) (nil 2 4))))
   (should (equal (seq-group-by #'car '((a 1) (b 3) (c 4) (a 2)))
-                 '((a (a 2) (a 1)) (b (b 3)) (c (c 4))))))
+                 '((b (b 3)) (c (c 4)) (a (a 1) (a 2))))))
 
 (provide 'seq-tests)
 ;;; seq-tests.el ends here