Re: attack of silly coding standard?

From:
Leigh Johnston <leigh@i42.co.uk>
Newsgroups:
comp.lang.c++
Date:
Wed, 08 Dec 2010 17:05:05 +0000
Message-ID:
<gLadneJ-ZOomJ2LRnZ2dnUVZ8tidnZ2d@giganews.com>
On 08/12/2010 16:59, Yannick Tremblay wrote:

In article<45d42867-bfec-462d-9e3f-b77b275bf780@d24g2000prj.googlegroups.com>,
hanukas<jukka@liimatta.org> wrote:

SESE may help making the compiled machine code smaller. Example;

const char* getError(GLenum error)
{
    switch (error)
    {
        case GL_BLA: return "bla";
        case GL_FOO: return "foo";
        // ... etc ...
    }
    // ... etc ...
}

YMMV, but often compilers replicate the return statement as many times
as you have case statements there. This will bloat the binary a lot.
There is a good mechanism to overcome that:


Arggh!

If the above code is causing your binary to bloat a lot you have either:

- Incredibly well optimised code
- A very different meaning of "a lot2"than I am used to.

const char* v;
switch (error)
{
    case GL_BLA: v = "bla"; break;
    // ... etc.
    default: v = "unknown error"; break;
}
return v;

Also use ## in a nice macro to save some typing when converting error
into string. ;-)

This was just one example that came to mind (probably because this is
a common case). Multiple returns are more often less clear than single
return, but doesn't mean it isn't true from time to time.

Rules like that are a good thing when you have junior staff members.
They will eventually learn what time it is and make good design calls
based on experience; when you have a good reason to have many exits,
by all means do it.


I think this is a very fundamental thing. I have authored coding
guidelines that contains some items that I do not believe should be
rules for experienced programmers. However, coding guidelines are at
their most useful as a set of reminders to more junior staff members
steering them towards best practices.

So for example, although I do not beleive that there exists a number
of lines per functions that is the threshold between a bad and a good
function, in some evironment, it can be worthwhile to place a rule
that say that all "all functions must be less than XX lines unless a
good explanation is provided".


Why provide a good explanation? Functions that contain switch
statements are often long and require no explanation. The following
function of mine is over 100 lines long and requires no explanation:

script::script(program& aProgram) : instance(Instance, aProgram),
iCompiling(false), iPass(1), iPuretime(false), iState(ParsingNamespace),
iTypeOk(false)
{
    add_namespace(scope::Global, L"");
    add_namespace(scope::Namespace, L"system");
    add_namespace(scope::Namespace, L"text");
    add_namespace(scope::Namespace, L"math");
    add_namespace(scope::Namespace, L"time");
    add_namespace(scope::Namespace, L"stdio");
    add_namespace(scope::Namespace, L"gui");
    add_namespace(scope::Namespace, L"media");
    add_namespace(scope::Namespace, L"irc");
    specific_namespace(L"system").symbol_table().insert(L"wait",
value(FunctionDefinition, function_ptr(new wait_1())));
    specific_namespace(L"system").symbol_table().insert(L"wait",
value(FunctionDefinition, function_ptr(new wait_2())));
    specific_namespace(L"system").symbol_table().insert(L"create_thread",
value(FunctionDefinition, function_ptr(new create_thread_1())));
    specific_namespace(L"system").symbol_table().insert(L"create_thread",
value(FunctionDefinition, function_ptr(new create_thread_2())));
    specific_namespace(L"system").symbol_table().insert(L"send",
value(FunctionDefinition, function_ptr(new send_object_1())));
    specific_namespace(L"system").symbol_table().insert(L"send",
value(FunctionDefinition, function_ptr(new send_object_2())));
    specific_namespace(L"system").symbol_table().insert(L"post",
value(FunctionDefinition, function_ptr(new post_object_1())));
    specific_namespace(L"system").symbol_table().insert(L"post",
value(FunctionDefinition, function_ptr(new post_object_2())));
    specific_namespace(L"system").symbol_table().insert(L"available",
value(FunctionDefinition, function_ptr(new available())));
    specific_namespace(L"system").symbol_table().insert(L"which",
value(FunctionDefinition, function_ptr(new which())));
    specific_namespace(L"system").symbol_table().insert(L"get",
value(FunctionDefinition, function_ptr(new get())));
    specific_namespace(L"system").symbol_table().insert(L"open",
value(FunctionDefinition, function_ptr(new resource::file_open())));
    specific_namespace(L"system").symbol_table().insert(L"read",
value(FunctionDefinition, function_ptr(new resource::file_read_1())));
    specific_namespace(L"system").symbol_table().insert(L"read",
value(FunctionDefinition, function_ptr(new resource::file_read_2())));
    specific_namespace(L"system").symbol_table().insert(L"read_line",
value(FunctionDefinition, function_ptr(new resource::file_read_line())));
    specific_namespace(L"system").symbol_table().insert(L"write",
value(FunctionDefinition, function_ptr(new resource::file_write_1())));
    specific_namespace(L"system").symbol_table().insert(L"write",
value(FunctionDefinition, function_ptr(new resource::file_write_2())));
    specific_namespace(L"system").symbol_table().insert(L"write_line",
value(FunctionDefinition, function_ptr(new resource::file_write_line())));
    specific_namespace(L"system").symbol_table().insert(L"seek_read",
value(FunctionDefinition, function_ptr(new resource::file_seek_read_1())));
    specific_namespace(L"system").symbol_table().insert(L"seek_read",
value(FunctionDefinition, function_ptr(new resource::file_seek_read_2())));
    specific_namespace(L"system").symbol_table().insert(L"tell_read",
value(FunctionDefinition, function_ptr(new resource::file_tell_read())));
    specific_namespace(L"system").symbol_table().insert(L"seek_write",
value(FunctionDefinition, function_ptr(new resource::file_seek_write_1())));
    specific_namespace(L"system").symbol_table().insert(L"seek_write",
value(FunctionDefinition, function_ptr(new resource::file_seek_write_2())));
    specific_namespace(L"system").symbol_table().insert(L"tell_write",
value(FunctionDefinition, function_ptr(new resource::file_tell_write())));
    specific_namespace(L"system").symbol_table().insert(L"is_good",
value(FunctionDefinition, function_ptr(new resource::file_is_good())));
    specific_namespace(L"system").symbol_table().insert(L"close",
value(FunctionDefinition, function_ptr(new resource::file_close())));
    specific_namespace(L"text").symbol_table().insert(L"tokens",
value(FunctionDefinition, function_ptr(new tokens())));
    specific_namespace(L"text").symbol_table().insert(L"to_utf8",
value(FunctionDefinition, function_ptr(new to_utf8())));
    specific_namespace(L"text").symbol_table().insert(L"from_utf8",
value(FunctionDefinition, function_ptr(new from_utf8())));
    specific_namespace(L"math").symbol_table().insert(L"set_precision",
value(FunctionDefinition, function_ptr(new ::set_precision())));
    specific_namespace(L"math").symbol_table().insert(L"set_fixed",
value(FunctionDefinition, function_ptr(new ::set_fixed())));
    specific_namespace(L"math").symbol_table().insert(L"set_scientific",
value(FunctionDefinition, function_ptr(new set_scientific())));
    specific_namespace(L"math").symbol_table().insert(L"hex",
value(FunctionDefinition, function_ptr(new hex())));
    specific_namespace(L"math").symbol_table().insert(L"oct",
value(FunctionDefinition, function_ptr(new oct())));
    specific_namespace(L"math").symbol_table().insert(L"from_hex",
value(FunctionDefinition, function_ptr(new from_hex())));
    specific_namespace(L"math").symbol_table().insert(L"from_oct",
value(FunctionDefinition, function_ptr(new from_oct())));
    specific_namespace(L"stdio").symbol_table().insert(L"print",
value(FunctionDefinition, function_ptr(new print())));
    specific_namespace(L"stdio").symbol_table().insert(L"print_line",
value(FunctionDefinition, function_ptr(new print_line())));
    specific_namespace(L"stdio").symbol_table().insert(L"input",
value(FunctionDefinition, function_ptr(new input())));
    specific_namespace(L"stdio").symbol_table().insert(L"input_line",
value(FunctionDefinition, function_ptr(new input_line())));
    specific_namespace(L"stdio").symbol_table().insert(L"ignore",
value(FunctionDefinition, function_ptr(new ignore())));
    specific_namespace(L"gui").symbol_table().insert(L"process_messages",
value(FunctionDefinition, function_ptr(new process_messages())));
    specific_namespace(L"gui").symbol_table().insert(L"next_message",
value(FunctionDefinition, function_ptr(new next_message_1())));
    specific_namespace(L"gui").symbol_table().insert(L"next_message",
value(FunctionDefinition, function_ptr(new next_message_2())));
    specific_namespace(L"gui").symbol_table().insert(L"__message_box",
value(FunctionDefinition, function_ptr(new message_box_1())));
    specific_namespace(L"gui").symbol_table().insert(L"__message_box",
value(FunctionDefinition, function_ptr(new message_box_2())));
    specific_namespace(L"gui").symbol_table().insert(L"create_window",
value(FunctionDefinition, function_ptr(new resource::create_window())));
    specific_namespace(L"gui").symbol_table().insert(L"destroy_window",
value(FunctionDefinition, function_ptr(new resource::destroy_window())));
    specific_namespace(L"gui").symbol_table().insert(L"register_message_procedure", value(FunctionDefinition, function_ptr(new resource::register_message_procedure())));
    specific_namespace(L"gui").symbol_table().insert(L"resize_client_area",
value(FunctionDefinition, function_ptr(new
resource::resize_client_area())));
    specific_namespace(L"gui").symbol_table().insert(L"create_canvas",
value(FunctionDefinition, function_ptr(new resource::create_canvas())));
    specific_namespace(L"gui").symbol_table().insert(L"plot",
value(FunctionDefinition, function_ptr(new resource::plot())));
    specific_namespace(L"gui").symbol_table().insert(L"clear",
value(FunctionDefinition, function_ptr(new resource::clear())));
    specific_namespace(L"media").symbol_table().insert(L"play_sound",
value(FunctionDefinition, function_ptr(new play_sound())));
    specific_namespace(L"math").symbol_table().insert(L"random",
value(FunctionDefinition, function_ptr(new random_0())));
    specific_namespace(L"math").symbol_table().insert(L"random",
value(FunctionDefinition, function_ptr(new random_1())));
    specific_namespace(L"math").symbol_table().insert(L"random",
value(FunctionDefinition, function_ptr(new random_2())));
    specific_namespace(L"math").symbol_table().insert(L"seed",
value(FunctionDefinition, function_ptr(new seed_())));
    specific_namespace(L"time").symbol_table().insert(L"time",
value(FunctionDefinition, function_ptr(new time_())));
    specific_namespace(L"time").symbol_table().insert(L"uptime",
value(FunctionDefinition, function_ptr(new uptime())));
    specific_namespace(L"math").symbol_table().insert(L"abs",
value(FunctionDefinition, function_ptr(new external_function_1<int,
int>(L"abs", &abs))));
    specific_namespace(L"math").symbol_table().insert(L"acos",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"acos", &acos))));
    specific_namespace(L"math").symbol_table().insert(L"asin",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"asin", &asin))));
    specific_namespace(L"math").symbol_table().insert(L"atan",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"atan", &atan))));
    specific_namespace(L"math").symbol_table().insert(L"atan2",
value(FunctionDefinition, function_ptr(new external_function_2<double,
double, double>(L"atan2", &atan2))));
    specific_namespace(L"math").symbol_table().insert(L"cos",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"cos", &cos))));
    specific_namespace(L"math").symbol_table().insert(L"cosh",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"cosh", &cosh))));
    specific_namespace(L"math").symbol_table().insert(L"exp",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"exp", &exp))));
    specific_namespace(L"math").symbol_table().insert(L"fabs",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"fabs", &fabs))));
    specific_namespace(L"math").symbol_table().insert(L"fmod",
value(FunctionDefinition, function_ptr(new external_function_2<double,
double, double>(L"fmod", &fmod))));
    specific_namespace(L"math").symbol_table().insert(L"log",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"log", &log))));
    specific_namespace(L"math").symbol_table().insert(L"log10",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"log10", &log10))));
    specific_namespace(L"math").symbol_table().insert(L"pow",
value(FunctionDefinition, function_ptr(new external_function_2<double,
double, double>(L"pow", &pow))));
    specific_namespace(L"math").symbol_table().insert(L"sin",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"sin", &sin))));
    specific_namespace(L"math").symbol_table().insert(L"sinh",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"sinh", &sinh))));
    specific_namespace(L"math").symbol_table().insert(L"tan",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"tan", &tan))));
    specific_namespace(L"math").symbol_table().insert(L"tanh",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"tanh", &tanh))));
    specific_namespace(L"math").symbol_table().insert(L"sqrt",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"sqrt", &sqrt))));
    specific_namespace(L"math").symbol_table().insert(L"ceil",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"ceil", &ceil))));
    specific_namespace(L"math").symbol_table().insert(L"floor",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"floor", &floor))));
    specific_namespace(L"math").symbol_table().insert(L"frexp",
value(FunctionDefinition, function_ptr(new frexp_())));
    specific_namespace(L"math").symbol_table().insert(L"hypot",
value(FunctionDefinition, function_ptr(new external_function_2<double,
double, double>(L"hypot", &_hypot))));
    specific_namespace(L"math").symbol_table().insert(L"_j0",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"_j0", &_j0))));
    specific_namespace(L"math").symbol_table().insert(L"_j1",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"_j1", &_j1))));
    specific_namespace(L"math").symbol_table().insert(L"_jn",
value(FunctionDefinition, function_ptr(new external_function_2<double,
int, double>(L"_jn", &_jn))));
    specific_namespace(L"math").symbol_table().insert(L"ldexp",
value(FunctionDefinition, function_ptr(new external_function_2<double,
double, int>(L"ldexp", &ldexp))));
    specific_namespace(L"math").symbol_table().insert(L"floor",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"floor", &floor))));
    specific_namespace(L"math").symbol_table().insert(L"_y0",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"_y0", &_y0))));
    specific_namespace(L"math").symbol_table().insert(L"_y1",
value(FunctionDefinition, function_ptr(new external_function_1<double,
double>(L"_y1", &_y1))));
    specific_namespace(L"math").symbol_table().insert(L"_yn",
value(FunctionDefinition, function_ptr(new external_function_2<double,
int, double>(L"_yn", &_yn))));
    specific_namespace(L"math").symbol_table().insert(L"modf",
value(FunctionDefinition, function_ptr(new modf_())));
    specific_namespace(L"irc").symbol_table().insert(L"message_create",
value(FunctionDefinition, function_ptr(new
resource::irc::message_create())));
    specific_namespace(L"irc").symbol_table().insert(L"message_id",
value(FunctionDefinition, function_ptr(new resource::irc::message_id())));
    specific_namespace(L"irc").symbol_table().insert(L"message_time",
value(FunctionDefinition, function_ptr(new resource::irc::message_time())));
    specific_namespace(L"irc").symbol_table().insert(L"message_is_ctcp",
value(FunctionDefinition, function_ptr(new
resource::irc::message_is_ctcp())));
    specific_namespace(L"irc").symbol_table().insert(L"message_direction",
value(FunctionDefinition, function_ptr(new
resource::irc::message_direction())));
    specific_namespace(L"irc").symbol_table().insert(L"message_origin",
value(FunctionDefinition, function_ptr(new
resource::irc::message_origin())));
    specific_namespace(L"irc").symbol_table().insert(L"message_command",
value(FunctionDefinition, function_ptr(new
resource::irc::message_command())));
    specific_namespace(L"irc").symbol_table().insert(L"message_command_as_string", value(FunctionDefinition, function_ptr(new resource::irc::message_command_as_string())));
    specific_namespace(L"irc").symbol_table().insert(L"message_target",
value(FunctionDefinition, function_ptr(new
resource::irc::message_target())));
    specific_namespace(L"irc").symbol_table().insert(L"message_parameter_count", value(FunctionDefinition, function_ptr(new resource::irc::message_parameter_count())));
    specific_namespace(L"irc").symbol_table().insert(L"message_parameter",
value(FunctionDefinition, function_ptr(new
resource::irc::message_parameter())));
    specific_namespace(L"irc").symbol_table().insert(L"message_set_direction", value(FunctionDefinition, function_ptr(new resource::irc::message_set_direction())));
    specific_namespace(L"irc").symbol_table().insert(L"message_set_origin",
value(FunctionDefinition, function_ptr(new
resource::irc::message_set_origin())));
    specific_namespace(L"irc").symbol_table().insert(L"message_set_command", value(FunctionDefinition, function_ptr(new resource::irc::message_set_command_1())));
    specific_namespace(L"irc").symbol_table().insert(L"message_set_command", value(FunctionDefinition, function_ptr(new resource::irc::message_set_command_2())));
    specific_namespace(L"irc").symbol_table().insert(L"message_add_parameter", value(FunctionDefinition, function_ptr(new resource::irc::message_add_parameter())));
    specific_namespace(L"irc").symbol_table().insert(L"buffer_type",
value(FunctionDefinition, function_ptr(new resource::irc::buffer_type())));
    specific_namespace(L"irc").symbol_table().insert(L"buffer_name",
value(FunctionDefinition, function_ptr(new resource::irc::buffer_name())));
    specific_namespace(L"irc").symbol_table().insert(L"buffer_send_message", value(FunctionDefinition, function_ptr(new resource::irc::buffer_send_message())));
    specific_namespace(L"irc").symbol_table().insert(L"buffer_send_command", value(FunctionDefinition, function_ptr(new resource::irc::buffer_send_command())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_name",
value(FunctionDefinition, function_ptr(new
resource::irc::connection_name())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_server_buffer", value(FunctionDefinition, function_ptr(new resource::irc::connection_server_buffer())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_buffer_from_name", value(FunctionDefinition, function_ptr(new resource::irc::connection_buffer_from_name())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_send_message", value(FunctionDefinition, function_ptr(new resource::irc::connection_send_message())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_send_command", value(FunctionDefinition, function_ptr(new resource::irc::connection_send_command())));
    specific_namespace(L"irc").symbol_table().insert(L"connection_receive_message", value(FunctionDefinition, function_ptr(new resource::irc::connection_receive_message())));
    specific_namespace(L"irc").symbol_table().insert(L"create_event_handler", value(FunctionDefinition, function_ptr(new resource::irc::create_event_handler())));
}

/Leigh

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