CSE 428: Quizzes

Please write your Name and Student ID at the top of the page. By default, this quiz will be returned in Section 2 (morning section).

[Pts 2] For each of the following datatypes, say whether it is polymorphic (aka parametric) or not

datatype 'a tree = empty | node of 'a tree * 'a * 'a tree;   yes

datatype ('a,'b) tree = leaf of 'a | node of ('a,'b) tree * 'b * ('a,'b) tree;   yes

datatype tree = empty | node of  tree * int * tree;   no

datatype direction = north | south | east | west;   no

[Pts 2] A polymorphic function is (only one answer, please)
- A function without name
- A function with many names
- A function which can be applied to data of different types
- A function with more than one argument
[Pts 2] One of the features of logic programming is (only one answer, please)
- each variable can be used only once
- each predicate can be used in only one query
- all variables must be declared
- each query can return several answers
[Pts 4] Consider the following definition of the mother and of the ancestor predicates:
```
   mother(a,b). /* a is mother of b */
   mother(a,c). /* a is mother of c */
   mother(c,d). /* c is mother of d */
   mother(d,e). /* d is mother of e */

   ancestor(X,Y) :- mother(X,Y).
   ancestor(X,Y) :- mother(X,Z), ancestor(Z,Y).
```
For each of the following queries, please indicate all the answers that are returned (assuming that we interactively keep asking for more answers). If no answers are returned, write "no". If the query generates an error, write "error".
- ?- mother(X,a). no
- ?- mother(a,Y). Y = b ; Y = c
- ?- ancestor(a,Y). Y = b ; Y = c ; Y = d ; Y = e
- ?- ancestor(X,b), ancestor(X,d). X = a ;