framework: add tabify-selection/reverse-choices to racket:text<%>

Add reverse-order tabbing for languages, like Rhombus, that support
iterating through tabbing alteratives. Map "s:tab" to iterate through
alternatives in reverse mode.

Merge before racket/drracket#753

Author: mflatt

gui-doc/scribblings/framework/racket.scrbl

@@ -84,6 +84,17 @@
     through @racket[end].
   }
 
+  @defmethod*[(((tabify-selection/reverse-choices (start exact-integer? (send this get-start-position))
+                                                  (end exact-integer? (send this get-end-position)))
+                void?))]{
+    Sets the tabbing for the lines containing positions @racket[start]
+    through @racket[end], but if there are multiple valid tabbings to cycle through,
+    this method should cycle through the choices in reverse order. The default
+    implementation calls @method[racket:text<%> tabify-selection].
+
+    @history[#:added "1.77"]
+  }
+
   @defmethod*[(((tabify-all) void?))]{
     Tabs all lines.
 

gui-lib/framework/private/racket.rkt

@@ -373,6 +373,7 @@
     tabify-on-return?
     tabify
     tabify-selection
+    tabify-selection/reverse-choices
     tabify-all
     insert-return
 
@@ -675,6 +676,10 @@
              (when (< first-para end-para)
                (end-busy-cursor)))))))
 
+    (define/public (tabify-selection/reverse-choices [start-pos (get-start-position)]
+                                                     [end-pos (get-end-position)])
+      (tabify-selection start-pos end-pos))
+
     (define/public (tabify-all) (tabify-selection 0 (last-position)))
     (define/public (insert-return)
       (begin-edit-sequence #t #f)
@@ -1714,6 +1719,8 @@
                      (λ (x) (send x select-up-sexp)))
   (add-edit-function "tabify-at-caret"
                      (λ (x) (send x tabify-selection)))
+  (add-edit-function "tabify-at-caret/reverse-choices"
+                     (λ (x) (send x tabify-selection/reverse-choices)))
   (add-edit-function "do-return"
                      (λ (x) (send x insert-return)))
   (add-edit-function "comment-out"
@@ -1827,6 +1834,7 @@
     (send keymap map-function key func))
 
   (map "TAB" "tabify-at-caret")
+  (map "s:TAB" "tabify-at-caret/reverse-choices")
 
   (map "return" "do-return")
   (map "s:return" "do-return")

gui-lib/info.rkt

@@ -34,7 +34,7 @@
 
 (define pkg-authors '(mflatt robby))
 
-(define version "1.76")
+(define version "1.77")
 
 (define license
   '(Apache-2.0 OR MIT))