colors.cmyk: make sure cmyka is a color.

diff --git a/extra/colors/cmyk/cmyk.factor b/extra/colors/cmyk/cmyk.factor
index ad38089a74dd137db4f4b792ac2c08cdb635a7f1..6492998d9b7a0d883f603c94baf883112a1de3f0 100644 (file)
--- a/extra/colors/cmyk/cmyk.factor
+++ b/extra/colors/cmyk/cmyk.factor
@@ -6,7 +6,7 @@ math.order ;
 
 IN: colors.cmyk
 
-TUPLE: cmyka
+TUPLE: cmyka < color
 { cyan read-only }
 { magenta read-only }
 { yellow read-only }