Assignment 6 for CSCI 431

PART I --- Prolog

Running Prolog:

Use the Java Prolog interpreter introduced in class or you can use this Prolog interpreter

Rules Exercises

Indicate whether the following are syntactically correct Rules.


a :-  b, c, d:- e f.

happy(X):- a , b.

happy(X):- hasmoney(X) & has_friends(X).

fun(fish):- blue(betty), bike(yamaha).

Given the database below, indicate whether you think a particular query will succeed or fail.


likes(john,mary).
likes(john,trains).
likes(peter,fast_cars).       

likes(Person1,Person2):-
hobby(Person1,Hobby),      
    hobby(Person2,Hobby).
       
hobby(john,trainspotting).       
hobby(tim,sailing). 
hobby(helen,trainspotting).                       
hobby(simon,sailing).

?- likes(john,trains).

?- likes(helen,john).

?- likes(tim,helen).

?- likes(john,helen).

Consider the following program.


a(X):-
     b(X), c(X), d(X).
a(X):-
     c(X), d(X).
a(X):-
     d(X).

b(1).                             
b(a).                            
b(2).
b(3).
d(10).
d(11).
c(3).
c(4).

Given the query ?- a(X). Indicate the successive variable bindings that the variable X gets when the above query is run. Separate bindings by a comma (ie. 1,3,5.....)

Lists Exercise

Here are some problems for which unification sometimes succeeds and sometimes fails. Decide which is the case and, if you think the unification succeeds, write down the substitutions made.
1. [a,d,z,c] and [H|T]
2. [apple,pear,grape] and [A,pear|Rest]
3. [a|Rest] and [a,b,c]
4. [a,[]] and [A,B|Rest]
5. [One] and [two|[]]
6. [one] and [Two]
7. [a,b,X] and [a,b,c,d]

Part II --- Ch 7

Consider the Pascal program below


PROGRAM MAIN(INPUT, OUTPUT) ;

  PROCEDURE P(V: INTEGER) ;
  VAR
     X: INTEGER ;

    PROCEDURE Q(V: INTEGER) ;
    BEGIN
      X := V ;
      WRITELN("In Q -- X = ", X:2, ", V = ", V:2) ;
    END ;

    PROCEDURE R(V: INTEGER) ;
      VAR
        X: INTEGER ;

      PROCEDURE S(V: INTEGER) ;
      BEGIN
         X := V ;
         Q(V+1) ;
         WRITELN("In S -- X = ", X:2, ", V = ", V:2) ;
      END ;
  
    BEGIN
      X := V ;
      S(V+1) ;
      WRITELN("In R -- X = ", X:2, ", V = ", V:2) ;
    END ;

  BEGIN
    X := V ;
    R(V+1) ;
    WRITELN("In P -- X = ", X:2, ", V = ", V:2);
    IF (V < 45000) THEN
       P(48048) ;
  END ;

BEGIN
   P(43680) ;
END .

Assuming static scoping, what will be printed?
Assuming dynamic scoping, what will be printed?

Consider the procedure BIGSUB in PL/1 syntax below. For each of the following parameter-passing methods, state the values in the array LIST in BIGSUB after the return from SUB:

parameters passed by value
parameters passed by reference
parameters passed by name
parameters passed by value-result


procedure BIGSUB;
           integer GLOBAL;
           integer array LIST[1..2];
           procedure SUB (PARAM);
              integer PARAM;  (declaration of type for the parameter PARAM)
              begin
              PARAM := 3;
              GLOBAL := GLOBAL +1;
              PARAM := 5;
              end (SUB);
          begin
          LIST[1] := 2;
          LIST[2] := 2;
          GLOBAL := 1;
          SUB(LIST[GLOBAL]);
          end (BIGSUB);

Show the run-time stack with activation record instances, including static and dynamic links, when execution reaches position 1 in the following skeletal program.



   procedure Main;
      procedure A;
         procedure B;
             begin { B }
                                <============ 1
             end; { B }
        procedure C;
             begin { C }
             
             B;
             
             end; { C }
      begin { A }
      
      C;
      
      end; { A }
   begin { Main }
   
   A;
   
   end; { Main }