diff --git a/core/flow-chart/flow-chart.factor b/core/flow-chart/flow-chart.factor
new file mode 100644
index 0000000000..5b6cb5f4f5
--- /dev/null
+++ b/core/flow-chart/flow-chart.factor
@@ -0,0 +1,74 @@
+USING: kernel words math inference.dataflow sequences
+optimizer.def-use combinators.private namespaces arrays
+math.parser assocs prettyprint io strings inference hashtables ;
+IN: flow-chart
+
+GENERIC: flow-chart* ( n word -- value nodes )
+
+M: word flow-chart*
+    2drop f f ;
+
+M: compound flow-chart*
+    word-def swap 1+ [ drop <computed> ] map
+    [ dataflow-with compute-def-use ] keep
+    first dup used-by prune [ t eq? not ] subset ;
+
+GENERIC: node-word ( node -- word )
+
+M: #call node-word node-param ;
+
+M: #if node-word drop \ if ;
+
+M: #dispatch node-word drop \ dispatch ;
+
+DEFER: flow-chart
+
+: flow-chart-node ( value node -- )
+    [ node-in-d <reversed> index ] keep
+    node-word flow-chart , ;
+
+SYMBOL: pruned
+
+SYMBOL: nesting
+
+SYMBOL: max-nesting
+
+2 max-nesting set
+
+: flow-chart ( n word -- seq )
+    [
+        2dup 2array ,
+        nesting dup inc get max-nesting get > [
+            2drop pruned ,
+        ] [
+            flow-chart* dup length 5 > [
+                2drop pruned ,
+            ] [
+                [ flow-chart-node ] curry* each
+            ] if
+        ] if
+    ] { } make ;
+
+: th ( n -- )
+    dup number>string write
+    100 mod dup 20 > [ 10 mod ] when
+    H{ { 1 "st" } { 2 "nd" } { 3 "rd" } } at "th" or write ;
+
+: chart-heading. ( pair -- )
+    first2 >r 1+ th " argument to " write r> . ;
+
+GENERIC# show-chart 1 ( seq n -- )
+
+: indent CHAR: \s <string> write ;
+
+M: sequence show-chart
+    dup indent
+    >r unclip chart-heading. r>
+    2 + [ show-chart ] curry each ;
+
+M: word show-chart
+    dup indent
+    "... pruned" print ;
+
+: flow-chart. ( n word -- )
+    flow-chart 2 show-chart ;
diff --git a/core/vocabs/loader/loader.factor b/core/vocabs/loader/loader.factor
index e9dc4f3e55..a7a112b58a 100644
--- a/core/vocabs/loader/loader.factor
+++ b/core/vocabs/loader/loader.factor
@@ -145,7 +145,7 @@ SYMBOL: load-help?
 : update-roots ( vocabs -- )
     [ dup find-vocab-root swap vocab set-vocab-root ] each ;
 
-: to-refresh ( prefix -- seq )
+: to-refresh ( prefix -- modified-sources modified-docs )
     child-vocabs
     dup update-roots
     dup modified-sources swap modified-docs ;