Sync

Task/Deepcopy/Deja-Vu/deepcopy.djv

@@ -0,0 +1,56 @@
+local :no-copy set{ :num :str :ident :pair :frac :func }
+(deepcopy) obj cache:
+	if has cache obj:
+		return get-from cache obj
+	if has no-copy type obj:
+		# this object is either immutable
+		# or a function object which can't be copied
+		return obj
+	if = :list type obj:
+		local :new []
+		set-to cache obj new
+		for value in reversed copy obj:
+			push-to new (deepcopy) value cache
+		return new
+	else:
+		local :new {}
+		set-to cache obj new
+		for key in keys obj:
+			set-to new (deepcopy) key cache (deepcopy) get-from obj key cache
+		return new
+
+deepcopy obj:
+	(deepcopy) obj {}
+
+#example usage:
+#a reasonably complicated object:
+set :A { :foo [ "bar" ] [] [ & 1 2 & 3 4 ] }
+set :B deepcopy A
+
+. A
+#prints: { [ ] [ & 1 2 & 3 4 ] :foo [ "bar" ] }
+. B
+#prints: { [ ] [ & 1 2 & 3 4 ] :foo [ "bar" ] }
+
+push-to get-from B :foo "HODOR"
+
+. A
+#prints: { [ ] [ & 1 2 & 3 4 ] :foo [ "bar" ] }
+. B
+#prints: { [ ] [ & 1 2 & 3 4 ] :foo [ "bar" "HODOR" ] }
+
+#it works with cycles:
+set :C push-through dup []
+set :D deepcopy C
+
+. C
+#prints: [ [ [ [ [...] ] ] ] ]
+. D
+#prints: [ [ [ [ [...] ] ] ] ]
+
+push-to C 7
+
+. C
+#prints: [ [ [ [ [...] 7 ] 7 ] 7 ] 7 ]
+. D
+#prints: [ [ [ [ [...] ] ] ] ]