assocs.extras: add intersect-keys-as and unit tests

[factor.git] / extra / assocs / extras / extras.factor

diff --git a/extra/assocs/extras/extras.factor b/extra/assocs/extras/extras.factor
index 8aee7d6d9db110e65d14d15979093f9d2586ae93..7073a074382ca3ed6fa105dcb0466d9b8327c444 100644 (file)
--- a/extra/assocs/extras/extras.factor
+++ b/extra/assocs/extras/extras.factor
@@ -217,8 +217,11 @@ PRIVATE>
 : flatten-values ( assoc -- assoc' )
     dup any-multi-value? [ expand-values-set-at flatten-values ] when ;
 
+: intersect-keys-as ( assoc seq exemplar -- elts )
+  [ [ of ] with ] dip zip-with-as sift-values ; inline
+
 : intersect-keys ( assoc seq -- elts )
-    [ of ] with zip-with sift-values ; inline
+    over intersect-keys-as ; inline
 
 : values-of ( assoc seq -- seq' )
     [ of ] with map ; inline