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9cacd33f47
This first step deals with the consequences of such removal.
The removal itself will happen in stage 2. That step will
add "is" to the prolog module in the library.
compiler/add_pred.m:
Prepare for "is" being in the prolog module.
compiler/options.m:
Add a way to test whether the change to add_pred.m is in the
installed compiler.
tests/accumulator/base.m:
tests/accumulator/call_in_base.m:
tests/accumulator/chain.m:
tests/accumulator/commutative.m:
tests/accumulator/construct_test.m:
tests/accumulator/dcg.m:
tests/accumulator/deconstruct_test.m:
tests/accumulator/disj.m:
tests/accumulator/func.m:
tests/accumulator/heuristic.m:
tests/accumulator/highorder.m:
tests/accumulator/identity.m:
tests/accumulator/inter.m:
tests/accumulator/nonrec.m:
tests/accumulator/out_to_in.m:
tests/accumulator/qsort.m:
tests/accumulator/simple.m:
tests/accumulator/split.m:
tests/accumulator/swap.m:
tests/benchmarks/cqueens.m:
tests/benchmarks/crypt.m:
tests/benchmarks/deriv.m:
tests/benchmarks/deriv2.m:
tests/benchmarks/nrev.m:
tests/benchmarks/poly.m:
tests/benchmarks/primes.m:
tests/benchmarks/qsort.m:
tests/benchmarks/query.m:
tests/benchmarks/tak.m:
tests/debugger/interactive.m:
tests/declarative_debugger/Mercury.options:
tests/declarative_debugger/io_read_bug.m:
tests/declarative_debugger/queens.exp:
tests/declarative_debugger/queens.m:
tests/dppd/imperative_solve_impl.m:
tests/dppd/map_impl.m:
tests/dppd/max_length_impl.m:
tests/dppd/sum.m:
tests/dppd/upto_sum_impl.m:
tests/par_conj/dep_par_21.m:
tests/tabling/seq.m:
tests/term/dds3_14.m:
tests/term/mmatrix.m:
tests/term/money.m:
tests/term/occur.m:
tests/term/pl4_5_2.m:
tests/term/queens.m:
tests/typeclasses/inference_test.m:
tests/typeclasses/inference_test_2.m:
tests/valid/lazy_list.m:
tests/warnings/duplicate_const.m:
Replace calls to "is" with unifications. In many places,
bring programming style up to date.
57 lines
1.0 KiB
Mathematica
57 lines
1.0 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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:- module queens.
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:- interface.
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:- type list(T)
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---> []
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; [T | list(T)].
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:- pred queens(list(int)::in, list(int)::out) is nondet.
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:- implementation.
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:- import_module int.
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:- import_module prolog.
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queens(X, Y) :-
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perm(X, Y),
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safe(Y).
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:- pred perm(list(T), list(T)).
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:- mode perm(in, out).
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perm([], []).
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perm([X | Y], [V | Res]) :-
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delete(V, [X | Y], Rest),
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perm(Rest, Res).
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:- pred delete(T, list(T), list(T)).
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:- mode delete(out, in, out).
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delete(X, [X | Y], Y).
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delete(X, [F | T], [F | R]) :-
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delete(X, T, R).
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:- pred safe(list(int)).
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:- mode safe(in).
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safe([]).
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safe([X | Y]) :-
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noattack(X, Y, 1),
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safe(Y).
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:- pred noattack(int, list(int), int).
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:- mode noattack(in, in, di).
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noattack(_X, [], _N).
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noattack(X, [F | T], N) :-
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X \= F,
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X \= F + N,
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F \= X + N,
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N1 = N + 1,
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noattack(X, T, N1).
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