README

NAME
    Debuggit - A fairly simplistic debug statement handler

SYNOPSIS
        use Debuggit DEBUG => 1;

        # say you have a global hashref for your site configuration
        # (not to imply that global vars are good)
        our $Config = get_global_config();

        # now we can set some config things based on whether we're in debug mode or not
        $Config->{'DB'} = DEBUG ? 'dev' : 'prod';

        # maybe we need to pull our local Perl modules from our VC working copy
        push @INC, $Config->{'vcdir/lib'} if DEBUG;

        # basic debugging output
        debuggit("only print this if debugging is on");
        debuggit(3 => "only print this if debugging is level 3 or higher");

        # show off our formatting
        my $var1 = 6;
        my $var2;
        my $var3 = " leading and trailing spaces   ";
        # assuming debugging is enabled ...
        debuggit("var1 is", $var1);   # var1 is 6
        debuggit("var2 is", $var2);   # var2 is <<undef>>
        debuggit("var3 is", $var3);   # var3 is << leading and trailing spaces   >>
        # note that spaces between args, as well as final newlines, are provided automatically

        # use "functions" in the debugging args list
        my $var4 = { complex => 'hash', with => 'lots', of => 'stuff' };
        # this will call Data::Dumper::Dumper() for you
        # (even if you've never loaded Data::Dumper)
        debuggit("var4 is", DUMP => $var4);

        # or maybe you prefer Data::Printer instead?
        use Debuggit DEBUG => 1, DataPrinter => 1;
        debuggit("var4 is", DUMP => $var4);

        # make your own function
        Debuggit::add_func(CONFIG => 1,
                sub { my ($self, $var) = $_; return (lc($self), 'var', $var, 'is', $Config->{$var}) });
        # and use it like so
        debuggit(CONFIG => 'DB');     # config var DB is dev

DESCRIPTION
    You want debugging? No, you want sophisticated, full-featured, on-demand
    debugging, and you don't want to take it out when you release the code
    because you might need it again later, but you also don't want it to
    take up any space or cause any slowdown of your production application.
    Sound impossible? Nah. Just use Debuggit.

  Quick Start
    To start:

        use strict;
        use warnings;

        use Debuggit;


        my $var = 6;
        debuggit(2 => "var is", $var);      # this does not print
        debuggit(4 => "var is", $var);      # neither does this

    Later ...

        use strict;
        use warnings;

        use Debuggit DEBUG => 2;


        my $var = 6;
        debuggit(2 => "var is", $var);      # now this prints
        debuggit(4 => "var is", $var);      # but this still doesn't

    That's it. Really. Everything else is just gravy.

  Documentation
    This POD explains just the basics of using "Debuggit". For full details,
    see Debuggit::Manual.

EXPORTS
  DEBUG
    DEBUG is a constant integer set to whatever value you choose:

        use Debuggit DEBUG => 2;

    or to 0 if you don't choose:

        use Debuggit;

    Actually, failure to specify a value only defaults to 0 the first time
    in a program this is seen. Subsequent times (e.g. in modules included by
    the main script), DEBUG will be set to the first value passed in. In
    this way, you can set DEBUG in the main script and have it "fall
    through" to all included modules. See "The DEBUG Constant" in
    Debuggit::Manual for full details.

  Functions exported
    Only "debuggit" is exported.

FUNCTIONS
  debuggit
    Use this function to conditionally print debugging output. If the first
    argument is a positive integer, the output is printed only if DEBUG is
    set to that number or higher. The remaining arguments are concatenated
    with spaces, a newline is appended, and the results are printed to
    STDERR. Some minor formatting is done to help distinguish "undef" values
    and values with leading or trailing spaces. To get further details, or
    to learn how to override any of those things, see "The debuggit
    function" in Debuggit::Manual.

  default_formatter
    This is what "debuggit" is set to initially. You can call it directly if
    you want to "wrap" "debuggit". For examples of this, see "Wrapping the
    debugging output" in Debuggit::Cookbook.

  add_func
  remove_func
    Add or remove debugging functions. Please see "Debugging Functions" in
    Debuggit::Manual.

DIAGNOSTICS
    *   Cannot redefine DEBUG; original value of %s is used

        It means you did something like this:

            use Debuggit DEBUG => 2;
            use Debuggit DEBUG => 3;

        only probably not nearly so obvious. Debuggit tries to be very
        tolerant of multiple imports into the same package, but the "DEBUG"
        symbol is a constant function and can't be redefined without
        engendering severe wonkiness, so Debuggit won't do it. As long as
        you pass the same value for "DEBUG", that's okay. But if the second
        (or more) value is different from the first, then you will get the
        original value regardless. At least this way you'll be forewarned.

PERFORMANCE
    Debuggit is designed to be left in your code, even when running in
    production environments. Because of this, it needs to disappear entirely
    when debugging is turned off. It can achieve this unlikely goal via the
    use of a compile-time constant. Please see "Performance Considerations"
    in Debuggit::Manual for full details.

BUGS and CAVEATS
    *   Once you set "DEBUG", you can't change it. Even if you try, you get
        the original value. See "DIAGNOSTICS".

    *   Doing:

            debuggit(0 => "in production mode");

        never prints anything, even when "DEBUG" is 0. That's because
        "debuggit" is guaranteed to be an empty function when debugging is
        turned off.

    *   Doing:

            debuggit($var, "is the value");

        is inherently dangerous. If $var is a positive integer, "debuggit"
        would interpret it as a debug level, and not print it. So, either do
        this:

            debuggit(1 => $var, "is the value");

        or this:

            debuggit("the value is", $var);

        Or, to look at it another way, you can pass a value as the first arg
        to print, or you can leave off a debugging level altogether, but
        don't try to do both at once.

    *   Doing:

            my $var1 = "DUMP";
            my $var2 = "stuff";
            debuggit(1 => "vars are", $var1, $var2);

        is equivalent to:

            debuggit(1 => "vars are", DUMP => $var2);

        which is probably not going to do what you want, assuming the
        default functions are still in place. See "IMPORTANT CAVEAT!" in
        Debuggit::Manual for full details.

    *   Doing:

            debuggit(2 => "first thousand elements:", @array[0..999]);

        is likely going to have a performance impact even when debugging is
        off. Instead, do:

            debuggit("first thousand elements:", @array[0..999]) if DEBUG >= 2;

        See "Style Considerations" in Debuggit::Manual for another example
        and details on the problem.

    That's all I know of. However, lacking omniscience, I welcome bug
    reports.

SUPPORT
    Debuggit is on GitHub at barefootcoder/debuggit. Feel free to fork and
    submit patches. Please note that I develop via TDD (Test-Driven
    Development), so a patch that includes a failing test is much more
    likely to get accepted (or least likely to get accepted more quickly).

    If you just want to report a problem or request a feature, that's okay
    too. You can create an issue on GitHub, or a bug in CPAN's RT (at
    http://rt.cpan.org). Or just send an email to bug-Debuggit@rt.cpan.org.

AUTHOR
        Buddy Burden
        CPAN ID: BAREFOOT
        Barefoot Software
        barefootcoder@gmail.com

COPYRIGHT
    This program is free software licensed under

        The Artistic License

    The full text of the license can be found in the LICENSE file included
    with this module.

    This module is copyright (c) 2008-2015, Barefoot Software. It has many
    venerable ancestors (some more direct than others), including but not
    limited to:

    *   "Barefoot::debug", (c) 2000-2006 Barefoot Software, 2004-2006
        ThinkGeek

    *   "Barefoot::base", (c) 2001-2006 Barefoot Software

    *   "Geek::Dev::Debug", (c) 2004 ThinkGeek

    *   "VCtools::Base", (c) 2004-2008 Barefoot Software, 2004 ThinkGeek

    *   "Barefoot", (c) 2006-2009 Barefoot Software

    *   "Company::Debug", (c) 2008 Rent.com

SEE ALSO
    Log::Log4perl, debug, Debug, Debug::Message, Debug::EchoMessage.

    Comparison with most of these (and others) can be found in "Comparison
    Matrix" in Debuggit::Manual.