[m-rev.] for post-commit review: improve consistency of usage message for mmc, mprof and mcov

[Zoltan Somogyi]

On 2023-09-04 17:20 +10:00 AEST, "Julien Fischer" <jfischer at opturion.com> wrote:
> @@ -3152,21 +3151,31 @@ long_usage(ProgressStream, !IO) :-
>      % copies of the long usage message. We can print both a short and along
>      % usage message, but there is no simple way to avoid that.
>      library.version(Version, Fullarch),
> -    Template =
> -        "Name: mmc -- Melbourne Mercury Compiler, version %s on %s\n" ++
> -        "Copyright (C) 1993-2012 The University of Melbourne\n" ++
> -        "Copyright (C) 2013-2023 The Mercury team\n" ++
> -        "Usage: mmc [<options>] <arguments>\n" ++
> -        "Arguments:\n" ++
> -        "\tArguments ending in `.m' are assumed to be source file names.\n" ++
> -        "\tArguments that do not end in `.m' " ++
> -            "are assumed to be module names.\n" ++
> -        "\tArguments in the form @file " ++
> -            "are replaced with the contents of the file.\n",
> -    io.format(ProgressStream, Template, [s(Version), s(Fullarch)], !IO),
> +    io.format(ProgressStream,
> +        "Name: mmc - Melbourne Mercury Compiler, version %s, on %s\n",
> +        [s(Version), s(Fullarch)], !IO),
> +    write_copyright_notice(ProgressStream, !IO),
> +    io.write_strings(ProgressStream, [
> +        "Usage: mmc [<options>] <arguments>\n",
> +        "Arguments:\n",
> +        "\tArguments ending in `.m' are assumed to be source file names.\n",
> +        "\tArguments that do not end in `.m' ",
> +            "are assumed to be module names.\n",
> +        "\tArguments in the form @file ",
> +            "are replaced with the contents of the file.\n"
> +    ], !IO),

Why not use write_prefixed_lines?

> +:- pred write_copyright_notice(io.text_output_stream::in, io::di, io::uo)
> +    is det.
> +
> +write_copyright_notice(Stream, !IO) :-
> +    io.write_strings(Stream, [
> +        "Copyright (C) 1993-2012 The University of Melbourne\n",
> +        "Copyright (C) 2013-2023 The Mercury team\n"
> +    ], !IO).

This code is still repeated in several places.

I would add a function to library/library.m that returns the copyright
message as a two-line string, and then just print that string with the
rest of whatever usage message each program has.

The diff is otherwise fine.

Zoltan.