week9 tweak

[lambda.git] / week9.mdwn

diff --git a/week9.mdwn b/week9.mdwn
index 568fc81..2b80483 100644 (file)
--- a/week9.mdwn
+++ b/week9.mdwn
@@ -291,7 +291,11 @@ Now we're going to relativize our interpretations not only to the assignment fun
 
 >      \[[expression]]<sub>g s</sub> = (value, s')
 
 
 >      \[[expression]]<sub>g s</sub> = (value, s')
 

-For expressions we already know how to interpret, `s'` will usually just be `s`. One exception is complex expressions like `let var = expr1 in expr2`. Part of interpreting this will be to interpret the sub-expression `expr1`, and we have to allow that in doing that, the store may have already been updated. We want to use that possibly updated store when interpreting `expr2`. Like this:
+For expressions we already know how to interpret, expect `s'` to just be `s`.
+An exception is complex expressions like `let var = expr1 in expr2`. Part of
+interpreting this will be to interpret the sub-expression `expr1`, and we have
+to allow that in doing that, the store may have already been updated. We want
+to use that possibly updated store when interpreting `expr2`. Like this:

 
        let rec eval expression g s =
                match expression with
 
        let rec eval expression g s =
                match expression with