X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=code%2Ftree_monadize.ml;h=55b0f7b0080a76510a940ff1916281c929472b28;hp=7c419a342402ce77a965eb1c2810e4b332cdfcde;hb=f502dd05e49a51cfb4e6c2f339764d99d0511c82;hpb=c9a9cb39ae6852c63c43d80ed4ebb05aec6c1e05

diff --git a/code/tree_monadize.ml b/code/tree_monadize.ml
index 7c419a34..55b0f7b0 100644
--- a/code/tree_monadize.ml
+++ b/code/tree_monadize.ml
@@ -115,7 +115,7 @@ let t1 = Node
 
 module Tree_monadizer(X : sig
   (* the module we're using as a parameter has to supply function values
-   * for unit and bind, as well as a monadic type constructor m *)
+   * for unit and bind, as well as a monadic type constructor *)
   type 'a monad
   val unit : 'a -> 'a monad
   val bind : 'a monad -> ('a -> 'b monad) -> 'b monad
@@ -197,7 +197,7 @@ let env = fun i -> i + i in
 TreeReader.monadize int_readerize t1 env;;
 
 (* You can also avoid declaring a separate toplevel TreeReader module
- * (or even a separate Reader_monad module) by ysing one of these forms:
+ * (or even a separate Reader_monad module) by using one of these forms:
  *     ...
  *     let module T = Tree_monadizer(Reader_monad) in
  *     T.monadize int_readerize t1 env;;
@@ -269,3 +269,27 @@ TreeCont.monadize (fun a k -> k [a; a*a]) t1 initial_continuation;;
 let initial_continuation = fun t -> 0 in
 TreeCont.monadize (fun a k -> 1 + k a) t1 initial_continuation;;
 
+(*
+(* Tree monad *)
+
+(* type 'a tree defined above *)
+let tree_unit (a: 'a) : 'a tree = Leaf a;;
+let rec tree_bind (u : 'a tree) (f : 'a -> 'b tree) : 'b tree =
+    match u with
+    | Leaf a -> f a
+    | Node (l, r) -> Node (tree_bind l f, tree_bind r f);;
+
+type ('a) treeT_reader =
+    'a tree reader;;
+
+let unit (a: 'a) : 'a tree reader =
+    reader_unit (Leaf a);;
+
+let rec bind (u : 'a tree_reader) (f : 'a -> ('b, M) tree) : ('b, M) tree =
+    match u with
+    | Leaf a -> M.bind (f a) (fun b -> M.unit (Leaf b))
+    | Node (l, r) -> M.bind (bind l f) (fun l' ->
+                        M.bind (bind r f) (fun r' ->
+                            M.unit (Node (l', r'));;
+
+ *)