      [ dup hashcode >fixnum ] [ root>> ] bi* (entry-at)
      dup [ value>> t ] [ f ] if ;
 
-M: persistent-hash new-at ( value key assoc -- assoc' )
+M: persistent-hash new-at
     [
         [ 0 ] 3dip
-        [ dup hashcode >fixnum ] [ root>> ] bi*
-        (new-at) 1 0 ?
-    ] [ count>> ] bi +
-    persistent-hash boa ;
+        [ dup hashcode >fixnum ] [ root>> ] bi* (new-at) 1 0 ?
+    ] [ count>> ] bi + persistent-hash boa ;
 
 M: persistent-hash pluck-at
     [ [ dup hashcode >fixnum ] [ root>> ] bi* (pluck-at) ] keep

! Based on Clojure's PersistentHashMap by Rich Hickey.

USING: kernel math accessors assocs fry combinators parser
prettyprint.custom locals make sequences
persistent.assocs
persistent.hashtables.nodes
persistent.hashtables.nodes.empty
persistent.hashtables.nodes.leaf
persistent.hashtables.nodes.full
persistent.hashtables.nodes.bitmap
persistent.hashtables.nodes.collision ;
IN: persistent.hashtables

TUPLE: persistent-hash
{ root read-only initial: empty-node }
{ count fixnum read-only } ;

M: persistent-hash assoc-size count>> ;



M: persistent-hash >alist [ root>> >alist% ] { } make ;

M: persistent-hash keys >alist keys ;

M: persistent-hash values >alist values ;

: >persistent-hash ( assoc -- phash )
    T{ persistent-hash } swap [ swap rot new-at ] assoc-each ;

M: persistent-hash equal?
    over persistent-hash? [ assoc= ] [ 2drop f ] if ;
