add get-colors' to color-database<%>'

collects/racket/draw/private/color.rkt

@@ -7,7 +7,8 @@
          color-green
          color-blue
          color-alpha
-         color-database<%> the-color-database
+         (rename-out [color-database-intf color-database<%>])
+         the-color-database
          color->immutable-color)
 
 (define-local-member-name
@@ -88,7 +89,13 @@
 
 (define color-objects (make-hash))
 
-(defclass color-database<%> object%
+(define color-database-intf
+  (let ([color-database<%> (interface ()
+                             find-color
+                             get-names)])
+    color-database<%>))
+
+(defclass* color-database<%> object% (color-database-intf)
   (super-new)
   (def/public (find-color [string? name])
     (let ([name (string-downcase name)])
@@ -100,7 +107,9 @@
                   (send c set-immutable)
                   (hash-set! color-objects name c)
                   c)
-                #f))))))
+                #f)))))
+  (def/public (get-names)
+    (sort (hash-map colors (lambda (k v) k)) string<?)))
 
 (define the-color-database (new color-database<%>))
 

collects/scribblings/draw/color-database-intf.scrbl

@@ -202,10 +202,16 @@ See also @racket[color%].
 
 
 @defmethod[(find-color [color-name string?])
-           (or/c (is-a?/c color%) false/c)]{
+           (or/c (is-a?/c color%) #f)]{
 
 Finds a color by name (character case is ignored). If no color is
- found for the name, @racket[#f] is returned.
+ found for the name, @racket[#f] is returned.}
 
-}}
+
+@defmethod[(get-names) (listof string?)]{
+
+Returns an alphabetically sorted list of case-folded color names for which
+@method[color-database<%> find-color] returns a @racket[color%] value.}
+
+}
 

doc/release-notes/racket/HISTORY.txt

@@ -4,6 +4,7 @@ Regexps are `equal?' when they have the same source [byte] string
 Numbers, characters, strings, byte strings, and regexps are interned by
  read and datum->syntax
 Added read-intern-literal
+racket/draw: added get-names to color-database<%>
 mzlib/pconvert: added add-make-prefix-to-constructor parameter,
  which changes the default constructor-style printing in DrRacket
  to avoid a make- prefix; the HtDP languages set the parameter to #t