ch06.078_best

来自「Perl Best Practices the source code」· 078_BEST 代码 · 共 57 行

##############################################################################
##   Code fragment (Recommended) from Chapter 6 of "Perl Best Practices"    ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;


package Debugging;
 
use Carp;
use Log::Stdlog  { level => 'debug' };
 
BEGIN {

# Choice of actions when debugging...
my %debug_mode = (
  # MODE           DEBUGGING ACTION
    off    => sub {},
    logged => sub { return print {*STDLOG} debug =>  @_; },
    loud   => sub {                  carp 'DEBUG: ', @_; },
    fatal  => sub {                 croak 'DEBUG: ', @_; },
);
 
# Change debugging behaviour whenever module is used...
sub import {
    my $package = shift;
    my $mode    = @_ > 0 ? shift : 'loud';   # Default to carping
 
    # Locate appropriate behaviour, or die trying...
    my $debugger = $debug_mode{$mode};
    croak "Unknown debugging mode ('$mode')" if !defined $debugger;
 
    # Install new behaviour...
    use Sub::Installer;
    caller()->reinstall_sub(debug  => $debugger);
 
    return;
}  

}


BEGIN { Debugging->import(); }


debug "Oops!";