assocs.extras: adding if-assoc-empty.

diff --git a/extra/assocs/extras/extras.factor b/extra/assocs/extras/extras.factor
index 383da2802cff845207632eb83a32093be229a71e..2c7f61cd565bb7a7b38aebbc0f12da6a7f5323b4 100644 (file)
--- a/extra/assocs/extras/extras.factor
+++ b/extra/assocs/extras/extras.factor
@@ -37,4 +37,5 @@ IN: assocs.extras
 
 : sum-values ( assoc -- n ) 0 [ + ] reduce-values ; inline
 
-
+: if-assoc-empty ( ..a assoc quot1: ( ..a -- ..b ) quot2: ( ..a assoc -- ..b ) -- ..b )
+    [ dup assoc-empty? ] [ [ drop ] prepose ] [ ] tri* if ; inline