package Off_hand_code;
use Exporter;
use Carp;

our @ISA = "Exporter";
our @EXPORT = qw/ routine /;
our @EXPORT_OK = qw/ set_debug /;

our $debug;    # current debug level


# debugging level definitions

use constant BUG => 1;
use constant TRACE => 2;

use constant ALL => 3;


# Set the $debug variable, complain if new setting is
# not an integer or is out of range (0 thru ALL).
# Tri-nature function.
#
sub set_debug {
    $debug = shift;
    $debug = shift if ref($debug) || $debug eq __PACKAGE__;
    no warnings;
    carp qq/Unexpected debug level "$debug"./ if
        ( $debug < 0 || $debug > ALL ) ||
        ($debug =~ /\D/ );
}


# With no args  return the current debugging level for package.
# With an arg return 0 unless arg is part of current debugging level.
#
sub _debug {
    carp "Wrong number of args to ",__PACKAGE__,"::_debug" if @_ > 1;
    return $debug unless @_;
    return $_[0] if $_[0] & $debug;
    return 0;
}


# XXX  set_debug_output( $output_method) 
# XXX  debug( $level, $output_method, $error_message) 
# instead of Carp::.* etc.

# a routine
#
sub routine {
    warn "debug message" if  _debug && "something";
    warn "trace message" if _debug(TRACE);
}