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b9c0ec0a21
Estimated hours taken: 0. Branches: main tests/debugger/declarative/sort.m: Import maybe instead of std_util.
150 lines
3.5 KiB
Mathematica
150 lines
3.5 KiB
Mathematica
%----------------------------------------------------------------------------%
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:- module sort.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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%----------------------------------------------------------------------------%
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%----------------------------------------------------------------------------%
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:- implementation.
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:- import_module exception.
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:- import_module int.
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:- import_module list.
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:- import_module maybe.
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:- import_module string.
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%----------------------------------------------------------------------------%
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:- type line == string.
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:- type lines == list(string).
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main(!IO) :-
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io.command_line_arguments(Args, !IO),
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open_stream(Args, MaybeStream, !IO),
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(
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MaybeStream = ok(InputStream),
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some [!Words] (
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read_lines(InputStream, !:Words, !IO),
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sort_lines(!Words),
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print_lines(!.Words, !IO)
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)
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;
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MaybeStream = error(ErrorMessage),
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io.stderr_stream(StdErr, !IO),
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io.format(StdErr, "%s\n", [s(ErrorMessage)], !IO),
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io.set_exit_status(1, !IO)
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).
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%----------------------------------------------------------------------------%
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:- pred open_stream(list(string)::in, maybe_error(io.input_stream)::out,
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io::di, io::uo) is det.
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open_stream([], MaybeStream, !IO) :-
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io.stdin_stream(Stdin, !IO),
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MaybeStream = ok(Stdin).
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open_stream([Arg], MaybeStream, !IO) :-
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io.open_input(Arg, MaybeStream0, !IO),
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(
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MaybeStream0 = ok(Stream),
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MaybeStream = ok(Stream)
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;
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MaybeStream0 = error(Error),
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io.error_message(Error, ErrorMessage),
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MaybeStream = error(ErrorMessage)
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).
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open_stream([_,_|_], error(ErrorMessage), !IO) :-
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ErrorMessage = "usage: sort [Input]".
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%----------------------------------------------------------------------------%
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:- pred read_lines(io.input_stream::in, lines::out, io::di, io::uo) is det.
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read_lines(Stream, Lines, !IO) :-
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read_lines_2(Stream, [], Lines, !IO).
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:- pred read_lines_2(io.input_stream::in, lines::in,
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lines::out, io::di, io::uo) is det.
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read_lines_2(Stream, !Lines, !IO) :-
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io.read_line_as_string(Stream, Result, !IO),
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(
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Result = ok(Line),
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list.cons(Line, !Lines),
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read_lines_2(Stream, !Lines, !IO)
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;
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Result = eof
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;
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Result = error(Error),
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io.error_message(Error, ErrorMessage),
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throw(ErrorMessage)
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).
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%----------------------------------------------------------------------------%
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:- pred sort_lines(lines::in, lines::out) is det.
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sort_lines(Us, Ss) :-
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N = list.length(Us),
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msort_n(N, Us, Ss, _).
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:- pred msort_n(int::in, lines::in, lines::out, lines::out) is det.
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msort_n(N, Unsorted, SortedPart, Rest) :-
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(
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N =< 0
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->
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SortedPart = [],
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Rest = Unsorted
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;
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N = 1
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->
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(
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Unsorted = [U | Us],
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SortedPart = [U],
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Rest = Us
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;
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Unsorted = [],
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throw("Unsorted = [] and N = 0")
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)
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;
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N1 = N // 2,
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sort.msort_n(N1, Unsorted, Ss1, Us2),
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N2 = N - N1,
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msort_n(N2, Us2, Ss2, Rest),
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sort.merge(Ss1, Ss2, SortedPart)
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).
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:- pred merge(lines::in, lines::in, lines::out) is det.
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merge([], [], []).
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merge([S | Ss], [], [S | Ss]).
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merge([], [S | Ss], [S | Ss]).
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merge([A | As], [B | Bs], [C | Cs]) :-
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compare(Cmp, A, B),
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(
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( Cmp = (<) ; Cmp = (=) )
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->
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sort.merge(As, [B | Bs], Cs),
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C = A
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;
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sort.merge(As, [B | Bs], Cs), % BUG
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C = B
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).
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%----------------------------------------------------------------------------%
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:- pred print_lines(lines::in, io::di, io::uo) is det.
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print_lines(Lines, !IO) :- io.write_list(Lines, "", io.write_string, !IO).
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%----------------------------------------------------------------------------%
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:- end_module sort.
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%----------------------------------------------------------------------------%
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