X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment1.mdwn;h=560d288ebc4e7687af786a57f1eccb4a67b05fca;hp=93136f22353c02033c4f263082ae015e017b1744;hb=8f9abe589a3b7c615b72adc6cbf57e7de1d931d3;hpb=97fd9ed2423e6c6d9e0dabdce6bc334f8439637f

diff --git a/assignment1.mdwn b/assignment1.mdwn
index 93136f22..560d288e 100644
--- a/assignment1.mdwn
+++ b/assignment1.mdwn
@@ -26,30 +26,34 @@ In Racket, these can be defined like this:
 	(define true (lambda (t) (lambda (f) t)))
 	(define false (lambda (t) (lambda (f) f)))
 
-8. [8] Define a "neg" operator that negates "true" and "false".
+* Define a "neg" operator that negates "true" and "false".
+
 Expected behavior: 
 
-    (((neg true) 10) 20) 
+    (((neg true) 10) 20)
 
 evaluates to 20, and 
 
-    (((neg false) 10) 20) 
+    (((neg false) 10) 20)
 
 evaluates to 10.
 
-9. [9] Define an "and" operator.
+* Define an "and" operator.
+
+* Define an "xor" operator. 
 
-10. [10] Define an "xor" operator. (If you haven't seen this term before, here's a truth table:
+(If you haven't seen this term before, here's a truth table:
 
-	true xor true = false
-	true xor false = true
-	false xor true = true
-	false xor false = false
+    true xor true = false
+    true xor false = true
+    false xor true = true
+    false xor false = false
 
 )
 
-* 11. Inspired by our definition of boolean values, propose a data structure
-capable of representing one of the two values "black" or "white". If we have
+* Inspired by our definition of boolean values, propose a data structure
+capable of representing one of the two values "black" or "white". 
+If we have
 one of those values, call it a black-or-white-value, we should be able to
 write:
 
@@ -60,7 +64,7 @@ if-white, depending on which of the black-or-white values we started with. Give
 a definition for each of "black" and "white". (Do it in both lambda calculus
 and also in Racket.)
 
-12. Now propose a data structure capable of representing one of the three values
+* Now propose a data structure capable of representing one of the three values
 "red" "green" or "blue," based on the same model. (Do it in both lambda
 calculus and also in Racket.)
 
@@ -80,8 +84,8 @@ To extract the first element of a pair p, you write:
 Here are some defintions in Racket:
 
         (define make-pair (lambda (fst) (lambda (snd) (lambda (f) ((f fst) snd)))))
-        (define get-first (lamda (fst) (lambda (snd) fst)))
-        (define get-second (lamda (fst) (lambda (snd) snd)))
+        (define get-first (lambda (fst) (lambda (snd) fst)))
+        (define get-second (lambda (fst) (lambda (snd) snd)))
 
 Now we can write: