add racket:current-tabify-reverse

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

Author: mflatt

gui-doc/scribblings/framework/racket.scrbl

@@ -74,18 +74,18 @@
   @defmethod*[(((tabify (start-pos exact-integer?
                                    (send this get-start-position)))
                 void?))]{
-    Tabs the line containing by @racket[start-pos]
+    Tabs the line containing by @racket[start-pos]. See also @racket[racket:current-tabify-reverse].
   }
 
   @defmethod*[(((tabify-selection (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].
+    through @racket[end]. See also @racket[racket:current-tabify-reverse].
   }
 
   @defmethod*[(((tabify-all) void?))]{
-    Tabs all lines.
+    Tabs all lines. See also @racket[racket:current-tabify-reverse].
 
   Indentation results depend on the graphical context associated with the object;
   if there is not one, the indentation is based on the assumption that a fixed-width

gui-lib/framework/main.rkt

@@ -1639,7 +1639,18 @@ are currently open in tabs.
   (listof (list/c symbol? symbol?))
   @{The default parentheses that are matched when using @racket[racket:text-mode-mixin].
 
- @history[#:added "1.60"]})
+        @history[#:added "1.60"]})
+
+ (parameter-doc
+  racket:current-tabify-reverse
+  (parameter/c boolean?)
+  reverse?
+  @{A parameter that indicates whether tabbing should cycle through options (if any) in reverse mode.
+      This parameter is meant to be set before calling @method[racket:text<%> tabify],
+      @method[racket:text<%> tabify-selection], or @method[racket:text<%> tabify-all],
+      although default implementations of those methods do not use the parameter.
+
+  @history[#:added "1.77"]})
 
  (proc-doc/names
   racket:add-preferences-panel

gui-lib/framework/private/racket.rkt

@@ -48,6 +48,8 @@
     ("[" . "]")
     ("{" . "}")))
 
+(define current-tabify-reverse (make-parameter #f))
+
 (define text-balanced?
   (lambda (text [start 0] [in-end #f])
     (let* ([end (or in-end (send text last-position))]
@@ -1714,6 +1716,9 @@
                      (λ (x) (send x select-up-sexp)))
   (add-edit-function "tabify-at-caret"
                      (λ (x) (send x tabify-selection)))
+  (add-edit-function "reverse-tabify-at-caret"
+                     (λ (x) (parameterize ([current-tabify-reverse #t])
+                              (send x tabify-selection))))
   (add-edit-function "do-return"
                      (λ (x) (send x insert-return)))
   (add-edit-function "comment-out"
@@ -1827,6 +1832,7 @@
     (send keymap map-function key func))
 
   (map "TAB" "tabify-at-caret")
+  (map "s:TAB" "reverse-tabify-at-caret")
 
   (map "return" "do-return")
   (map "s:return" "do-return")

gui-lib/framework/private/sig.rkt

@@ -418,7 +418,8 @@
 
      text-balanced?
 
-     default-paren-matches))
+     default-paren-matches
+     current-tabify-reverse))
 
   (define-signature main-class^ ())
   (define-signature main^ extends main-class^ ())

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))