Updated doc.

README.md

@@ -55,25 +55,22 @@ DogSingleton = immutable(0, {name="DogSingleton", bark=function(self) print("woo
 DogSingleton():bark()
 ```
 
-## Tuple recipe
-With immutable tables, it's pretty simple to emulate Python-like tuples:
+## Tuples
+If no field names are passed in, `immutable()` defaults to creating immutable tables that behave like Python's tuples:
 ```lua
-local tuple_classes = {}
-Tuple = function(...)
-    local n = select('#', ...)
-    if not tuple_classes[n] then
-        tuple_classes[n] = immutable(n)
-    end
-    return tuple_classes[n](...)
-end
-assert(Tuple(5,6,7) == Tuple(5,6,7))
-assert(tostring(Tuple(8,9)) == "(8, 9)")
+local Tuple = immutable()
+local t0 = Tuple()
+local t1 = Tuple(1,2)
+local t2 = Tuple(1,2,3,4,5)
+assert(t0 == Tuple())
+assert(({[t1]='yep'})[Tuple(1,2)])
+assert(tostring(Tuple(1,2)) == "(1, 2)")
 ```
 
 ## General purpose immutable table recipe
-Using the tuple recipe above, you can make a function that returns an immutable version
-of a table with arbitrary keys.
+Using tuples, you can make a function that returns an immutable version of a table with arbitrary keys, though it is a little bit hacky.
 ```lua
+local Tuple = immutable()
 local immutable_classes = {}
 Immutable = function(t)
     local keys = {}