diff --git a/table.lua b/table.lua
index ca14fcf..b96f89b 100644
--- a/table.lua
+++ b/table.lua
@@ -321,6 +321,22 @@ function foreach(table, func)
 	end
 end
 
+function deep_foreach_any(table, func)
+	local seen = {}
+	local function visit(value)
+		func(value)
+		if type(value) == "table" then
+			if seen[value] then return end
+			seen[value] = true
+			for k, v in pairs(value) do
+				visit(k)
+				visit(v)
+			end
+		end
+	end
+	visit(table)
+end
+
 function foreach_value(table, func)
 	for _, v in pairs(table) do
 		func(v)
diff --git a/test.lua b/test.lua
index 1ac2a16..e230c8e 100644
--- a/test.lua
+++ b/test.lua
@@ -61,6 +61,24 @@ do
 	rope:write" "
 	rope:write"world"
 	assert(rope:to_text() == "hello world", rope:to_text())
+	tab = {a = 1, b = {2}}
+	tab[3] = tab
+	local contents = {
+		a = 1,
+		[1] = 1,
+		b = 1,
+		[tab.b] = 1,
+		[2] = 1,
+		[tab] = 1,
+		[3] = 1
+	}
+	table.deep_foreach_any(tab, function(content)
+		assert(contents[content], content)
+		contents[content] = 2
+	end)
+	for _, value in pairs(contents) do
+		assert(value == 2)
+	end
 end
 
 -- heap