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a653024ab7
If we want to encourage people to read the sample programs
and learn Mercury programming from them, they should not be written
in an obsolete style.
samples/beer.m:
samples/calculator.m:
samples/calculator2.m:
samples/concurrency/midimon/midimon.m:
samples/diff/diff_out.m:
samples/e.m:
samples/eliza.m:
samples/muz/dict.m:
samples/muz/higher_order.m:
samples/muz/muz.m:
samples/muz/typecheck.m:
samples/muz/word.m:
samples/muz/zabstract.m:
samples/muz/zlogic.m:
samples/muz/zparser.m:
samples/muz/ztoken.m:
samples/muz/ztoken_io.m:
samples/muz/ztype.m:
samples/muz/ztype_op.m:
samples/rot13/rot13_concise.m:
samples/rot13/rot13_gustavo.m:
samples/rot13/rot13_juergen.m:
samples/rot13/rot13_ralph.m:
samples/rot13/rot13_verbose.m:
samples/solutions/all_solutions.m:
samples/solutions/n_solutions.m:
samples/solutions/one_solution.m:
samples/solutions/some_solutions.m:
samples/solver_types/eqneq.m:
samples/solver_types/sudoku.m:
samples/solver_types/test_eqneq.m:
Replace uses of __ as module qualifier with dot.
Replace (C->T;E) with (if C then T else E).
Use our usual indentation for if-then-elses and for switches.
Import one module per line. Put those imports into alphabetical order.
Replace many uses of DCGs with state variables, leaving DCGs
mostly just for parsing code.
Use predmode declarations where this helps.
Put predicates in top-down order where relevant.
Use io.format where this helps.
Do not put more than one predicate call on one line.
Put each function symbol in a du type on a separate line.
Put spaces after commas, around the bar in list syntax,
around arithmetic operators, and around minus signs used for pairs.
Replace tab indentation with four-space indentation.
Delete spaces at the ends of lines.
Replace two or more consecutive blank lines with one blank line.
Delete blank lines that do not help structure the code.
There are probably still some examples of old practices remaining;
I do not claim to have fixed them all.
55 lines
1.6 KiB
Mathematica
55 lines
1.6 KiB
Mathematica
% An example program to illustrate the use of the `do_while'
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% predicate in Mercury. This program calls a nondeterministic
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% predicate hello/1, prints the first solution it finds, and
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% then asks the user if they want any more solutions;
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% if they do, it finds another solution, prompts the user again,
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% and so on. It stops when there are no more solutions or
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% when the user says no to the "More?" prompt.
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%
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% Note that in the standard "commutative" semantics, the order of
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% solutions is unspecified. If you want to force the order of
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% evaluation, then you would need to use the "strict sequential semantics"
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% (enabled by the `--strict-sequential' option to the Mercury compiler).
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% This source file is hereby placed in the public domain. -fjh (the author).
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:- module some_solutions.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is cc_multi.
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:- implementation.
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:- import_module bool.
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:- import_module char.
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:- import_module list.
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:- import_module solutions.
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main(!IO) :-
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do_while(hello, get_next, !IO),
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io.write_string("No (more) solutions\n", !IO).
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:- pred hello(string::out) is multi.
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hello("Hello, world\n").
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hello("Good day, world\n").
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hello("Greetings, world\n").
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:- pred get_next(string::in, bool::out, io::di, io::uo) is det.
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get_next(String, More, !IO) :-
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% print the first answer
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io.write_string(String, !IO),
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% see if the user wants more answers
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io.write_string("More? ", !IO),
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io.read_line(Line, !IO),
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( if
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Line = ok([FirstChar | _]),
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char.to_upper(FirstChar, 'Y')
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then
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More = yes
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else
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More = no
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).
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