✎ pp:l11 [books]

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====== Generative predicates ======

1. Write the predicate ''sublist/2'' which constructs **each** sublist of a given list. Hint: use ''append''.
<code>
?- sublist([7,2,9],R).
% R will subsequently be bound to [], [7], [2], [9], [7,2], [2,9], [7,2,9] 
</code>

2. Rewrite the predicate such that the empty list is reported only once.

3. Write the predicate ''natlist/1'' which generates **each** finite list of natural number in ascending order.
<code>
?- natlist(R).
R = [0] ;
R = [0,1] ;
R = [0,1,2] ; 
...
</code>

4. Write the predicate ''oddOnly/2'' which removes all even integers from a list.
<code>
?- oddOnly([1,2,3,4],R).
R = [2,4].
</code>

5. Write the predicate ''oddList/1'' which generates all finite lists of odd numbers, in ascending order.

6. Write a predicate ''eqelem/1'' which generates all lists of **uninstantiated** variables which must be equal. Example:
<code>
?- eqelem(L), length(L,3), L=[0|_].
L = [0,0,0].
</code>

7. Use the previous predicate to write ''repeat/3'' which returns a list containing the same value ''X'' repeated ''K'' times.

8. Write a function ''pal/1'' which generates **all** lists of palindroms. Hint: use only ''append''.

9.