# More on Lists #
+<a id=comprehensions></a>
## Comprehensions ##
We know you are already familiar with the following kind of notation for designating sets:
[ 10*x + y | y <- [4, 5, 6] | x <- [1, 2, 3] ]
-will evaluate to `[14, 25, 36]`. If the lists are of unequal length, Haskell stops when it exhausts the first. These behaviors are similar to the `map2` function you defined in the week 1 homework. That also took an argument from each of several sequences in parallel. (The corresponding functions in Haskell are called `zip` and `zipWith`.)
+will evaluate to `[14, 25, 36]`. If the lists are of unequal length, Haskell stops when it exhausts the shortest. These behaviors are similar to the `map2` function you defined in the week 1 homework. That also took an argument from each of several sequences in parallel. (The corresponding functions in Haskell are called `zip` and `zipWith`.)
OCaml [permits lists comprehensions as an extension](http://stackoverflow.com/questions/27652428/list-comprehension-in-ocaml), and [so too does Scheme](http://srfi.schemers.org/srfi-42/srfi-42.html), but these are a bit harder to use.
To get the latter, you'd need to apply `join` twice.
+
+<a id=tails></a>
## Tails ##
For the Lambda Calculus, we've proposed to encode lists in terms of higher-order functions that perform right-folds on (what we intuitively regard as) the real list. Thus, the list we'd write in Kapulet or Haskell as:
and the result will be `\f z. f b (f c z)`, our encoding of `[b, c]`.
+
+<a id=v2-lists></a>