From 409efc67477072cceb755f567d5ba380ddcbe61c Mon Sep 17 00:00:00 2001 From: jim Date: Thu, 19 Feb 2015 10:07:17 -0500 Subject: [PATCH 1/1] add anchor for imp --- topics/week3_unit.mdwn | 1 + 1 file changed, 1 insertion(+) diff --git a/topics/week3_unit.mdwn b/topics/week3_unit.mdwn index f599227c..762f63bf 100644 --- a/topics/week3_unit.mdwn +++ b/topics/week3_unit.mdwn @@ -160,6 +160,7 @@ and Scheme will display the result like this: --- perhaps with a further single-quote prefix, depending on your configuration. It's also possible to specify a vector using that latter syntax. Vectors are like tuples in Kapulet, Haskell, and OCaml, in that their different elements can be of heterogenous types. They are like Kapulet's heavyweight tuples in that they can be assigned to single variables, can be discrete elements in other structures, including other vectors, and so on. Scheme vectors are *unlike* the tuple structures in the other languages in that they are usually *mutable*: one and numerically the same vector container can contain different elements at different stages in the program's evaluation. But some Scheme implementations also have immutable vectors. + The other notion in Scheme for expressing longer *n*-tuples is what I'll call the possibly-improper list, or **imp**. (This isn't standard Scheme terminology. I think it's conceptually cleaner to start here and work your way toward the standard Scheme ways of talking.) I won't say yet how you tell Scheme to construct an imp, but they are displayed like this: (5 0 . #f) -- 2.11.0