edits

[lambda.git] / topics / week12_list_and_tree_zippers.mdwn

diff --git a/topics/week12_list_and_tree_zippers.mdwn b/topics/week12_list_and_tree_zippers.mdwn
index 2f5d5dc..3f7ca7a 100644 (file)
--- a/topics/week12_list_and_tree_zippers.mdwn
+++ b/topics/week12_list_and_tree_zippers.mdwn
@@ -213,7 +213,7 @@ siblings of the focussed tree:
 
     Branch (Leaf 2, Leaf 3), ([], [Leaf 4])
 
-We still need to add the rest of the context.  But just computed that
+We still need to add the rest of the context.  But we just computed that
 context a minute ago.  It was ([Leaf 1], []).  If we add it here, we get:
 
     Branch (Leaf 2, Leaf 3), ([], [Leaf 4], ([Leaf 1], [])
@@ -223,13 +223,13 @@ Here's the type suggested by this idea:
     type context = Root | Context of (tree list) * (tree list) * context
     type zipper = tree * context
 
-We can gloss `Context of (tree list) * (tree list) * context` as 
-`Context of (left siblings) * (right siblings) * (context of parent)`.
+We can gloss the triple `(tree list) * (tree list) * context` as 
+`(left siblings) * (right siblings) * (context of parent)`.
 
 Here, then, is the full tree zipper we've been looking for:
 
-  (Branch [Leaf 2; Leaf 3],
-   Context ([], [Leaf 4], Context ([Leaf 1], [], Root)))
+    (Branch [Leaf 2; Leaf 3],
+     Context ([], [Leaf 4], Context ([Leaf 1], [], Root)))
 
 Just as with the simple list zipper, note that elements that are near
 the focussed element in the tree are near the focussed element in the