Revert "graphs: change closure to use a set and operate on sequences."

This reverts commit 2cc201a38a.

core/classes/classes.factor

@@ -130,11 +130,9 @@ GENERIC: implementors ( class/classes -- seq )
         tri
     ] { } make ;
 
-: class-usage ( class -- seq )
-    update-map get at keys ;
+: class-usage ( class -- seq ) update-map get at ;
 
-: class-usages ( class -- seq )
-    [ class-usage ] closure sets:members ;
+: class-usages ( class -- seq ) [ class-usage ] closure keys ;
 
 M: class implementors implementors-map get at sets:members ;
 
@@ -172,7 +170,7 @@ GENERIC: metaclass-changed ( use class -- )
 : check-metaclass ( class metaclass -- usages/f )
     over class? [
         over "metaclass" word-prop eq?
-        [ drop f ] [ class-usage ] if
+        [ drop f ] [ class-usage keys ] if
     ] [ 2drop f ] if ;
 
 : ?define-symbol ( word -- )

core/classes/tuple/tuple.factor

@@ -298,7 +298,7 @@ PRIVATE>
 GENERIC: make-final ( class -- )
 
 M: tuple-class make-final
-    [ dup class-usage ?metaclass-changed ]
+    [ dup class-usage keys ?metaclass-changed ]
     [ t "final" set-word-prop ]
     bi ;
 

core/graphs/graphs-docs.factor

@@ -1,5 +1,4 @@
-USING: assocs hashtables help.markup help.syntax kernel
-sequences sets ;
+USING: assocs hashtables help.markup help.syntax kernel sequences ;
 IN: graphs
 
 ARTICLE: "graphs" "Directed graph utilities"
@@ -29,5 +28,5 @@ HELP: remove-vertex
 { $side-effects "graph" } ;
 
 HELP: closure
-{ $values { "obj" object } { "quot" { $quotation "( obj -- assoc )" } } { "set" set } }
+{ $values { "obj" object } { "quot" { $quotation "( obj -- assoc )" } } { "assoc" "a new assoc" } }
 { $description "Outputs a set of all vertices reachable from " { $snippet "vertex" } " via edges given by the quotation. The set always includes " { $snippet "vertex" } "." } ;

core/graphs/graphs-tests.factor

@@ -1,5 +1,4 @@
 USING: graphs tools.test namespaces kernel sorting assocs ;
-FROM: sets => members ;
 
 H{ } "g" set
 { 1 2 3 } "v" set
@@ -15,7 +14,7 @@ H{
 } "g" set
 
 [ { 2 3 4 5 } ] [
-    2 [ "g" get at keys ] closure members natural-sort
+    2 [ "g" get at ] closure keys natural-sort 
 ] unit-test
 
 H{ } "g" set

core/graphs/graphs.factor

@@ -31,12 +31,15 @@ PRIVATE>
 
 <PRIVATE
 
-: (closure) ( obj set quot: ( elt -- seq ) -- )
-    2over ?adjoin [
-        [ dip ] keep [ (closure) ] 2curry each
-    ] [ 3drop ] if ; inline recursive
+: (closure) ( obj assoc quot: ( elt -- assoc ) -- )
+    2over key? [
+        3drop
+    ] [
+        2over conjoin [ dip ] keep
+        [ [ drop ] 3dip (closure) ] 2curry assoc-each
+    ] if ; inline recursive
 
 PRIVATE>
 
-: closure ( obj quot -- set )
-    HS{ } clone [ swap (closure) ] keep ; inline
+: closure ( obj quot -- assoc )
+    H{ } clone [ swap (closure) ] keep ; inline