List Sorting

[MinasTirith]

?Hey guys,

Im working on a family structure file tutorial and I am trying to sort a list using a bubble sort in descending order of salary. I have to firstly find all the person structures in the file whose salary are between 15000 & 35000 inclusive. Then sort them by salary and print them out.

The family structure I am using is:

family(
	person(alan,sartre,date(5,may,1962),works(mopper-ups,15000)),
	person(caitlin,sartre,date(11,october,1964),works(limolux,100000)),
	[	person(yvonne,sartre,date(12,november,1991),unemployed),
		person(alan_jr,sartre,date(4,august,1989),unemployed)
	]

My code is:

q18_get_list(List):-
	findall(Person, passes_test(Person), List).

passes_test(Person):-
	Person = person(Name, Surname, Dob, works(Co, Salary),
	exists(Person),
	Salary >= 15000,
	Salary =< 35000.
Syntax Error here!!!

bubblesort(List, Sorted):-
	swap(List, List1),!,
	bubblesort(List1, Sorted).
	bubblesort(Sorted, Sorted).

swap([X,Y|Rest], [Y,X|Rest]):-
	X<Y,
swap([Z|Rest], [Z,Rest1]).


print_list:-
	nl,nl,
	mylist(List),
	write_out(List).

write_out([Head|Tail]):-
	write(Head),
	nl,
	write_out(Tail).

write_out([]):-
	nl,nl.

I keep getting a syntax error just below the passes_test predicate. Could someone point me in the right direction as to where I am going wrong? Im really confused on this one.

Thanks
MT

 

[MinasTirith]

Ok I managed to sort the syntax error, didnt close my brackets of properly, but now I am getting an Error 20 Predicate not defined:

! Error 20 : Predicate Not Defined
! Goal : bubblesort(_37214,_37216) :- swap(_37214,_37232),!,bubblesort(_37232,_37216)

Not sure what the numbers mean or where exactly the error is, I am pretty new to prolog.