hydra.el (hydra--sort-heads): change ordering method of columns

The order was based upon the alphabetical order of the column name.
It is now done upon the order in which column name first appear in defhydra.

hydra-test.el

@@ -1442,7 +1442,7 @@ t: info-to"
 ;; column compatibility with ruby style and no colum specified
 ;; column declared several time
 ;; nil column
-(ert-deftest hydra-column-1 ()
+(ert-deftest hydra-column-basic ()
   (should (equal (eval
                   (cadr
                    (nth 2
@@ -1507,6 +1507,54 @@ o: ok       | s: string
                    270 272 (face hydra-face-pink)
                    296 298 (face hydra-face-pink)))))
 
+;; check column order is the same as they appear in defhydra
+(ert-deftest hydra-column-order ()
+  (should (equal (eval
+                  (cadr
+                   (nth 2
+                        (nth 3
+                             (macroexpand
+                              '(defhydra hydra-window-order
+                                 (:color red :hint nil :timeout 4)
+                                 ("z" ace-window "ace" :color blue :column "Switch")
+                                 ("h" windmove-left "← window")
+                                 ("j" windmove-down "↓ window")
+                                 ("l" windmove-right "→ window")
+                                 ("s" split-window-below "split window" :color blue :column "Split Management")
+                                 ("v" split-window-right "split window vertically" :color blue)
+                                 ("d" delete-window "delete current window")
+                                 ("f" follow-mode "toogle follow mode")
+                                 ("u" winner-undo "undo window conf" :column "Undo/Redo")
+                                 ("r" winner-redo "redo window conf")
+                                 ("b" balance-windows "balance window height" :column "1-Sizing")
+                                 ("m" maximize-window "maximize current window")
+                                 ("k" windmove-up "↑ window" :column "Switch")
+                                 ("M" minimize-window "maximize current window" :column "1-Sizing")
+                                 ("q" nil "quit menu" :color blue :column nil)))))))
+                 #("hydra:
+Switch      | Split Management           | Undo/Redo           | 1-Sizing
+----------- | -------------------------- | ------------------- | --------------------------
+z: ace      | s: split window            | u: undo window conf | b: balance window height
+h: ← window | v: split window vertically | r: redo window conf | m: maximize current window
+j: ↓ window | d: delete current window   |                     | M: maximize current window
+l: → window | f: toogle follow mode      |                     |
+k: ↑ window |                            |                     |
+[q]: quit menu."
+                   173 174 (face hydra-face-blue)
+                   187 188 (face hydra-face-blue)
+                   216 217 (face hydra-face-red)
+                   238 239 (face hydra-face-red)
+                   263 264 (face hydra-face-red)
+                   277 278 (face hydra-face-blue)
+                   306 307 (face hydra-face-red)
+                   328 329 (face hydra-face-red)
+                   355 356 (face hydra-face-red)
+                   369 370 (face hydra-face-red)
+                   420 421 (face hydra-face-red)
+                   447 448 (face hydra-face-red)
+                   461 462 (face hydra-face-red)
+                   512 513 (face hydra-face-red)
+                   578 579 (face hydra-face-blue)))))
 
 (provide 'hydra-test)
 

hydra.el

@@ -1002,12 +1002,17 @@ was defined."
             heads)))
 
 (defun hydra--sort-heads (normalized-heads)
-  "Return a list of heads with non-nil doc sorted by ascending column property
-each head of NORMALIZED-HEADS must have a column property"
+  "Return a list of heads with non-nil doc grouped by column property.
+Each head of NORMALIZED-HEADS must have a column property."
   (let* ((heads-wo-nil-doc (cl-remove-if-not (lambda (head) (nth 2 head)) normalized-heads))
+         (columns-list (delete-dups (mapcar (lambda (head) (hydra--head-property head :column))
+                                            normalized-heads)))
+         (get-col-index-fun (lambda (head) (cl-position (hydra--head-property head :column)
+                                                        columns-list
+                                                        :test 'equal)))
          (heads-sorted (cl-sort heads-wo-nil-doc (lambda (it other)
-                                                   (string< (hydra--head-property it :column)
-                                                            (hydra--head-property other :column))))))
+                                                   (< (funcall get-col-index-fun it)
+                                                      (funcall get-col-index-fun other))))))
     ;; this operation partition the sorted head list into lists of heads with same column property
     (cl-loop for head in heads-sorted
        for column-name = (hydra--head-property head :column)