X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=hints%2Fassignment_7_hint_6.mdwn;h=38f6c2e09b38449cd7bdda53b8aeb7c8c6a6b9a9;hp=0d9f02e8af9f33c454cfadef6dc6ce8ddf37dd95;hb=eb8ac48a126c26a8195d19dfc0e1f60009198746;hpb=c6f572fd09dbe53dff30a91cd07b318b3e5edfd6

diff --git a/hints/assignment_7_hint_6.mdwn b/hints/assignment_7_hint_6.mdwn
index 0d9f02e8..38f6c2e0 100644
--- a/hints/assignment_7_hint_6.mdwn
+++ b/hints/assignment_7_hint_6.mdwn
@@ -27,6 +27,8 @@
 				in unit_set new_dpm;;
 
 
+	**Note: Simon pointed out a subtle error in this code, which we will look into fixing. At the moment, the subtle error is still there.**
+
 *	Representing \[[and φ ψ]] is simple:
 
 		let and_op (phi : clause) (psi : clause) : clause =
@@ -39,7 +41,7 @@
 		let or_op (phi : clause) (psi : clause) =
             fun one_dpm -> unit_set (
                 fun (r, h) ->
-					in let truth_value' = (
+					let truth_value' = (
 						truths (phi one_dpm) (r, h) <> [] ||
 						truths (bind_set (negate_op phi one_dpm) psi) (r, h) <> []
 					) in (truth_value', r, h))
@@ -47,7 +49,7 @@
 		let if_op (phi : clause) (psi : clause) : clause =
             fun one_dpm -> unit_set (
               fun (r, h) ->
-					in let truth_value' = List.for_all (fun one_dpm ->
+					let truth_value' = List.for_all (fun one_dpm ->
 							let (truth_value, _, _) = one_dpm (r, h)
 							in truth_value = false || truths (psi one_dpm) (r, h) <> []
 						) (phi one_dpm)
@@ -76,6 +78,8 @@
 
 		type clause = bool dpm -> bool dpm set;;
 
+*	More:
+
 		(* this generalizes the getx function from hint 4 *)
 		let get (var : char) : entity dpm =
 			fun (r, h) ->
@@ -100,8 +104,6 @@
 					else bind_dpm entity1_dpm (fun e1 -> bind_dpm entity2_dpm (fun e2 -> unit_dpm (f e1 e2)))
 				in fun one_dpm -> unit_set (bind_dpm one_dpm eliminator);;
 
-&nbsp;
-
 		let new_peg_and_assign (var_to_bind : char) (d : entity) : bool -> bool dpm =
 		  fun truth_value ->
 			  fun (r, h) ->
@@ -119,6 +121,8 @@
 
 		(* include negate_op, and_op, or_op, and if_op as above *)
 
+*	More:
+
 		(* some handy utilities *)
 		let (>>=) = bind_set;;
 		let getx = get 'x';;