edits

[lambda.git] / week7.mdwn

diff --git a/week7.mdwn b/week7.mdwn
index 62ef89f..a78a77e 100644 (file)
--- a/week7.mdwn
+++ b/week7.mdwn
@@ -48,22 +48,24 @@ that provides at least the following three elements:
   use a container metaphor: if `x` has type `int option`, then `x` is
   a box that (may) contain an integer.
 
-    type 'a option = None | Some of 'a;;
+    `type 'a option = None | Some of 'a;;`
 
 * A way to turn an ordinary value into a monadic value.  In Ocaml, we
   did this for any integer n by mapping an arbitrary integer `n` to
   the option `Some n`.  To be official, we can define a function
   called unit:
 
-    let unit x = Some x;;
-    val unit : 'a -> 'a option = <fun>
+    `let unit x = Some x;;`
+
+    `val unit : 'a -> 'a option = <fun>`
 
     So `unit` is a way to put something inside of a box.
 
 * A bind operation (note the type):
 
-     let bind m f = match m with None -> None | Some n -> f n;;
-     val bind : 'a option -> ('a -> 'b option) -> 'b option = <fun>
+     `let bind m f = match m with None -> None | Some n -> f n;;`
+
+     `val bind : 'a option -> ('a -> 'b option) -> 'b option = <fun>`
 
      `bind` takes two arguments (a monadic object and a function from
      ordinary objects to monadic objects), and returns a monadic
@@ -75,7 +77,7 @@ that provides at least the following three elements:
      Then the second argument uses `x` to compute a new monadic
      value.  Conceptually, then, we have
 
-    let bind m f = (let x = unwrap m in f x);;
+    `let bind m f = (let x = unwrap m in f x);;`
 
     The guts of the definition of the `bind` operation amount to
     specifying how to unwrap the monadic object `m`.  In the bind
@@ -103,14 +105,14 @@ them from hurting the people that use them or themselves.
      object, we have `(unit x) * f == f x`.  For instance, `unit` is a
      function of type `'a -> 'a option`, so we have
 
-<pre>
-# let ( * ) m f = match m with None -> None | Some n -> f n;;
-val ( * ) : 'a option -> ('a -> 'b option) -> 'b option = <fun>
-# let unit x = Some x;;
-val unit : 'a -> 'a option = <fun>
-# unit 2 * unit;;
-- : int option = Some 2
-</pre>
+    <pre>
+    # let ( * ) m f = match m with None -> None | Some n -> f n;;
+    val ( * ) : 'a option -> ('a -> 'b option) -> 'b option = <fun>
+    # let unit x = Some x;;
+    val unit : 'a -> 'a option = <fun>
+    # unit 2 * unit;;
+    - : int option = Some 2
+    </pre>
 
        The parentheses is the magic for telling Ocaml that the
        function to be defined (in this case, the name of the function