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https://github.com/Mercury-Language/mercury.git
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5db4b3befd
Estimated hours taken: 4 Make declarative debugging enabled by default, and add test cases. The declarative debugger, while not complete, is fairly stable so users will be able to experiment with it after this change without having to re-configure the whole system. However, the main motivation for this change is so that developers who make changes to the system will have access to these test cases. configure.in: Turn the decl-debug feature on by default. tests/debugger/declarative: New directory containing tests for the declarative debugger. tests/debugger/declarative/*.m: tests/debugger/declarative/*.inp: tests/debugger/declarative/*.exp: Declarative debugger test cases. tests/debugger/declarative/Mmakefile: Mmakefile to do the declarative debugger tests. tests/debugger/Mmakefile: For each target, make the corresponding target in the 'declarative' subdirectory. WORK_IN_PROGRESS: Document the new (incomplete) feature.
102 lines
1.6 KiB
Mathematica
102 lines
1.6 KiB
Mathematica
:- module queens.
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:- interface.
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:- import_module io.
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:- pred main(io__state, io__state).
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:- mode main(di, uo) is cc_multi.
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:- implementation.
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:- import_module list, int.
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main -->
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( { data(Data), queen(Data, Out) } ->
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print_list(Out)
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;
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io__write_string("No solution\n")
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).
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:- pred data(list(int)).
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:- mode data(out) is det.
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:- pred queen(list(int), list(int)).
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:- mode queen(in, out) is nondet.
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:- pred qperm(list(T), list(T)).
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:- mode qperm(in, out) is nondet.
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:- pred qdelete(T, list(T), list(T)).
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:- mode qdelete(out, in, out) is nondet.
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:- pred safe(list(int)).
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:- mode safe(in) is semidet.
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:- pred nodiag(int, int, list(int)).
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:- mode nodiag(in, in, in) is semidet.
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data([1,2,3,4,5]).
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queen(Data, Out) :-
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qperm(Data, Out),
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safe(Out).
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qperm([], []).
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qperm([X|Y], K) :-
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qdelete(U, [X|Y], Z),
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K = [U|V],
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qperm(Z, V).
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qdelete(A, [A|L], L).
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qdelete(X, [A|Z], [A|R]) :-
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qdelete(X, Z, R).
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safe([]).
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safe([N|L]) :-
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nodiag(N, 1, L),
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safe(L).
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nodiag(_, _, []).
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nodiag(B, D, [N|L]) :-
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NmB is N - B,
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BmN is B - N,
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( D = NmB ->
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fail
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; D = BmN ->
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fail
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;
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true
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),
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D1 is D + 1,
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nodiag(B, D1, L).
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:- pred print_list(list(int), io__state, io__state).
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:- mode print_list(in, di, uo) is det.
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print_list(Xs) -->
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(
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{ Xs = [] }
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->
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io__write_string("[]\n")
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;
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io__write_string("["),
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print_list_2(Xs),
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io__write_string("]\n")
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).
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:- pred print_list_2(list(int), io__state, io__state).
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:- mode print_list_2(in, di, uo) is det.
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print_list_2([]) --> [].
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print_list_2([X|Xs]) -->
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io__write_int(X),
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(
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{ Xs = [] }
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->
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[]
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;
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io__write_string(", "),
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print_list_2(Xs)
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).
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