(define true (lambda (t) (lambda (f) t)))
(define false (lambda (t) (lambda (f) f)))
- [8] Define a "neg" operator that negates "true" and "false".
+ 8. Define a "neg" operator that negates "true" and "false".
+
Expected behavior:
(((neg true) 10) 20)
evaluates to 10.
- [9] Define an "and" operator.
+ 9. Define an "and" operator.
+
+ 10. Define an "xor" operator.
- [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
+ 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: