interleave: allow the 'between' quot to access the stack

basis/ui/gadgets/gadgets.factor

@@ -112,8 +112,7 @@ M: gadget gadget-text-separator
     orientation>> vertical = "\n" "" ? ;
 
 : gadget-seq-text ( seq gadget -- )
-    gadget-text-separator swap
-    [ dup % ] [ gadget-text* ] interleave drop ;
+    gadget-text-separator '[ _ % ] [ gadget-text* ] interleave ;
 
 M: gadget gadget-text*
     [ children>> ] keep gadget-seq-text ;

core/sequences/sequences-tests.factor

@@ -286,3 +286,8 @@ M: bogus-hashcode hashcode* 2drop 0 >bignum ;
 [ f f ] [
     { 1 2 3 4 5 6 7 8 } [ H{ { 11 "hi" } } at ] map-find
 ] unit-test
+
+USE: make
+
+[ { "a" 1 "b" 1 "c" } ]
+[ 1 { "a" "b" "c" } [ [ dup , ] [ , ] interleave drop ] { } make ] unit-test

core/sequences/sequences.factor

@@ -406,6 +406,9 @@ PRIVATE>
     [ 2drop f f ]
     if ; inline
 
+: interleave-step ( elt between quot -- )
+    [ dip ] dip call ; inline
+
 PRIVATE>
 
 : each ( seq quot -- )
@@ -510,7 +513,7 @@ PRIVATE>
 : interleave ( seq between quot -- )
     pick empty? [ 3drop ] [
         [ [ drop first-unsafe ] dip call ]
-        [ [ rest-slice ] 2dip [ [ call ] bi@ ] 2curry each ]
+        [ [ rest-slice ] 2dip [ interleave-step ] 2curry each ]
         3bi
     ] if ; inline