assignment7 tweaks

[lambda.git] / hints / assignment_7_hint_3.mdwn

diff --git a/hints/assignment_7_hint_3.mdwn b/hints/assignment_7_hint_3.mdwn
index 46e9639..0914b79 100644 (file)
--- a/hints/assignment_7_hint_3.mdwn
+++ b/hints/assignment_7_hint_3.mdwn
@@ -27,8 +27,6 @@
 
        we'll just talk about \[[expression]] and let that be a monadic value, implemented in part by a function that takes `(r, h)` as an argument.
 
 
        we'll just talk about \[[expression]] and let that be a monadic value, implemented in part by a function that takes `(r, h)` as an argument.
 

-       More specifically, \[[expression]] will be a set of `'a dpm`s, where `'a` is the appropriate type for *expression*. Each `'a dpm` is implemented by a function that takes `(r, h)` as an argument.
-

 *      In def 2.7, GS&V talk about an operation that takes an existing set of discourse possibilities, and *extends* each member in the set by (i) allocating a new location in the store, (ii) putting some entity `d` from the domain in that location, and (iii) assigning variable `x` to that location in the store.
 It will be useful to have a shorthand way of referring to this operation:
 
 *      In def 2.7, GS&V talk about an operation that takes an existing set of discourse possibilities, and *extends* each member in the set by (i) allocating a new location in the store, (ii) putting some entity `d` from the domain in that location, and (iii) assigning variable `x` to that location in the store.
 It will be useful to have a shorthand way of referring to this operation:
 


@@ -42,7 +40,8 @@ It will be useful to have a shorthand way of referring to this operation:
                                (* next we assign 'x' to location newindex *)
                                in let r' = fun v ->
                                        if v = var_to_bind then newindex else r v
                                (* next we assign 'x' to location newindex *)
                                in let r' = fun v ->
                                        if v = var_to_bind then newindex else r v

-                               in (r',h')
+                               (* the reason for returning true as an initial element will emerge later *)
+                               in (true, r',h')

 
 *      Is that enough? If not, here are some [more hints](/hints/assignment_7_hint_4).
 
 
 *      Is that enough? If not, here are some [more hints](/hints/assignment_7_hint_4).