From 7d27bb2510dd466a8c8135d83b3dc0150ce93bef Mon Sep 17 00:00:00 2001
From: Jim Pryor <profjim@jimpryor.net>
Date: Wed, 1 Dec 2010 00:30:24 -0500
Subject: [PATCH] lists-to-contin tweaks

Signed-off-by: Jim Pryor <profjim@jimpryor.net>
---
 from_lists_to_continuations.mdwn | 78 ++++++++++++++++++----------------------
 1 file changed, 34 insertions(+), 44 deletions(-)

diff --git a/from_lists_to_continuations.mdwn b/from_lists_to_continuations.mdwn
index c67d5e86..be7e17f5 100644
--- a/from_lists_to_continuations.mdwn
+++ b/from_lists_to_continuations.mdwn
@@ -19,9 +19,7 @@ updated version.
 
 Expected behavior:
 
-<pre>
-t "abSd" ~~> "ababd"
-</pre>   
+	t "abSd" ~~> "ababd"
 
 
 In linguistic terms, this is a kind of anaphora
@@ -32,39 +30,33 @@ This deceptively simple task gives rise to some mind-bending complexity.
 Note that it matters which 'S' you target first (the position of the *
 indicates the targeted 'S'):
 
-<pre>
-    t "aSbS" 
-        *
-~~> t "aabS" 
-          *
-~~> "aabaab"
-</pre>
+	    t "aSbS" 
+	        *
+	~~> t "aabS" 
+	          *
+	~~> "aabaab"
 
 versus
 
-<pre>
-    t "aSbS"
-          *
-~~> t "aSbaSb" 
-        *
-~~> t "aabaSb"
-           *
-~~> "aabaaabab"
-</pre>   
+	    t "aSbS"
+	          *
+	~~> t "aSbaSb" 
+	        *
+	~~> t "aabaSb"
+	           *
+	~~> "aabaaabab"
 
 versus
 
-<pre>
-    t "aSbS"
-          *
-~~> t "aSbaSb"
-           *
-~~> t "aSbaaSbab"
-            *
-~~> t "aSbaaaSbaabab"
-             *
-~~> ...
-</pre>
+	    t "aSbS"
+	          *
+	~~> t "aSbaSb"
+	           *
+	~~> t "aSbaaSbab"
+	            *
+	~~> t "aSbaaaSbaabab"
+	             *
+	~~> ...
 
 Aparently, this task, as simple as it is, is a form of computation,
 and the order in which the `'S'`s get evaluated can lead to divergent
@@ -80,20 +72,18 @@ zipper `unzipped` and `zipped`; we start with a fully zipped list, and
 move elements to the zipped part by pulling the zipper down until the
 entire list has been unzipped (and so the zipped half of the zipper is empty).
 
-<pre>
-type 'a list_zipper = ('a list) * ('a list);;
-
-let rec tz (z:char list_zipper) = 
-    match z with (unzipped, []) -> List.rev(unzipped) (* Done! *)
-               | (unzipped, 'S'::zipped) -> tz ((List.append unzipped unzipped), zipped) 
-               | (unzipped, target::zipped) -> tz (target::unzipped, zipped);; (* Pull zipper *)
-
-# tz ([], ['a'; 'b'; 'S'; 'd']);;
-- : char list = ['a'; 'b'; 'a'; 'b'; 'd']
-
-# tz ([], ['a'; 'S'; 'b'; 'S']);;
-- : char list = ['a'; 'a'; 'b'; 'a'; 'a'; 'b']
-</pre>
+	type 'a list_zipper = ('a list) * ('a list);;
+	
+	let rec tz (z:char list_zipper) = 
+	    match z with (unzipped, []) -> List.rev(unzipped) (* Done! *)
+	               | (unzipped, 'S'::zipped) -> tz ((List.append unzipped unzipped), zipped) 
+	               | (unzipped, target::zipped) -> tz (target::unzipped, zipped);; (* Pull zipper *)
+	
+	# tz ([], ['a'; 'b'; 'S'; 'd']);;
+	- : char list = ['a'; 'b'; 'a'; 'b'; 'd']
+	
+	# tz ([], ['a'; 'S'; 'b'; 'S']);;
+	- : char list = ['a'; 'a'; 'b'; 'a'; 'a'; 'b']
 
 Note that this implementation enforces the evaluate-leftmost rule.
 Task completed.
-- 
2.11.0