Fix inspector problem with empty hashtables

library/test/inspector.factor

@@ -13,3 +13,4 @@ V{ } clone inspector-stack set
 f (inspect)
 \ + (inspect)
 H{ } (inspect)
+H{ } describe

library/tools/describe.factor

@@ -78,8 +78,12 @@ M: word summary ( word -- )
 DEFER: describe
 
 : sheet. ( sheet -- )
-    dup format-sheet swap peek
-    [ dup [ describe ] curry simple-outliner terpri ] 2each ;
+    dup empty? [
+        drop
+    ] [
+        dup format-sheet swap peek
+        [ dup [ describe ] curry simple-outliner terpri ] 2each
+    ] if ;
 
 : describe ( object -- ) dup summary print sheet sheet. ;
 

library/tools/inspector.factor

@@ -8,8 +8,10 @@ prettyprint sequences words ;
 SYMBOL: inspector-slots
 
 : sheet-numbers ( sheet -- sheet )
-    dup first length >array 1array swap append
-    dup peek inspector-slots set ;
+    dup empty? [
+        dup first length >array 1array swap append
+        dup peek inspector-slots set
+    ] unless ;
 
 SYMBOL: inspector-stack
 
@@ -18,7 +20,7 @@ SYMBOL: inspector-stack
 : (inspect) ( obj -- )
     dup inspector-stack get push
     dup summary print
-    sheet dup empty? [ drop ] [ sheet-numbers sheet. ] if ;
+    sheet sheet-numbers sheet. ;
 
 : inspector-help ( -- )
     "Object inspector." print