X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=code%2Fcalculator%2Fcalc4.ml;h=1343827d69844c6bd5386af8f76ac2dd7dc8d62b;hp=a04587b86291b3fc143ccd6f2400e9ce6dfc88ce;hb=573a8b36ce653c84c2aecb2b81ef99128cb41d13;hpb=38f178b5967f0875383d87a92330ecd58979f83e

diff --git a/code/calculator/calc4.ml b/code/calculator/calc4.ml
index a04587b8..1343827d 100644
--- a/code/calculator/calc4.ml
+++ b/code/calculator/calc4.ml
@@ -1,4 +1,4 @@
-(* calc3.ml, enhanced with Mutable Cells *)
+(* calc4.ml: calc3.ml enhanced with Mutable Cells *)
 
     type term =
       Intconstant of int
@@ -88,12 +88,12 @@
         in let g' = (var_to_bind, Recursive_Closure (var_to_bind, arg_var, body, savedg)) :: g
         in eval t3 g' s'
     | Newref (t1) ->
-        let (starting_val, s') = eval t1 g s
+        let (value1, s') = eval t1 g s
         (* note that s' may be different from s, if t1 itself contained any mutation operations *)
         (* now we want to retrieve the next free index in s' *)
         in let new_index = List.length s'
-        (* now we want to insert starting_val there; the following is an easy but inefficient way to do it *)
-        in let s'' = List.append s' [starting_val]
+        (* now we want to insert value1 there; the following is an easy but inefficient way to do it *)
+        in let s'' = List.append s' [value1]
         (* now we return a pair of a wrapped new_index, and the new store *)
         in (Mutcell new_index, s'')
     | Deref (t1) ->
@@ -105,12 +105,12 @@
         (* we don't handle cases where t1 doesn't evaluate to a Mutcell *)
         let (Mutcell index1, s') = eval t1 g s
         (* note that s' may be different from s, if t1 itself contained any mutation operations *)
-        in let (new_value, s'') = eval t2 g s'
-        (* now we create a list which is just like s'' except it has new_value in index1 *)
+        in let (value2, s'') = eval t2 g s'
+        (* now we create a list which is just like s'' except it has value2 in index1 *)
         in let rec replace_nth lst m =
             match lst with
             | [] -> failwith "list too short"
-            | x::xs when m = 0 -> new_value :: xs
+            | x::xs when m = 0 -> value2 :: xs
             | x::xs -> x :: replace_nth xs (m - 1)
         in let s''' = replace_nth s'' index1
         (* we'll arbitrarily return Int 42 as the expressed_value of a Setref operation *)