X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=zipper-lists-continuations.mdwn;h=a9d0e8faa237e271f7ca44b8de76d80b5d9afaa5;hb=449ca8e544f4f19ddfc567850014d94b6b985598;hp=bfd144c1ede17257d7847957abf1fded70590127;hpb=aeec785e1d00c613973b4912d4b0f510954491ec;p=lambda.git

diff --git a/zipper-lists-continuations.mdwn b/zipper-lists-continuations.mdwn
index bfd144c1..a9d0e8fa 100644
--- a/zipper-lists-continuations.mdwn
+++ b/zipper-lists-continuations.mdwn
@@ -26,10 +26,10 @@ constructor is
 
 then we can deduce the unit and the bind:
 
-    runit x:'a -> 'a reader = fun (e:env) -> x
+    r_unit x:'a -> 'a reader = fun (e:env) -> x
 
 Since the type of an `'a reader` is `fun e:env -> 'a` (by definition),
-the type of the `runit` function is `'a -> e:env -> 'a`, which is a
+the type of the `r_unit` function is `'a -> e:env -> 'a`, which is a
 specific case of the type of the *K* combinator.  So it makes sense
 that *K* is the unit for the reader monad.
 
@@ -43,13 +43,14 @@ We can deduce the correct `bind` function as follows:
 
 We have to open up the `u` box and get out the `'a` object in order to
 feed it to `f`.  Since `u` is a function from environments to
-objects of type `'a`, we'll have
+objects of type `'a`, the way we open a box in this monad is
+by applying it to an environment:
 
          .... f (u e) ...
 
 This subexpression types to `'b reader`, which is good.  The only
-problem is that we don't have an `e`, so we have to abstract over that
-variable:
+problem is that we invented an environment `e` that we didn't already have ,
+so we have to abstract over that variable to balance the books:
 
          fun e -> f (u e) ...