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require 5;
package Pod::Simple::Debug;
use strict;
sub import {
my($value,$variable);
if(@_ == 2) {
$value = $_[1];
} elsif(@_ == 3) {
($variable, $value) = @_[1,2];
($variable, $value) = ($value, $variable)
if defined $value and ref($value) eq 'SCALAR'
and not(defined $variable and ref($variable) eq 'SCALAR')
; # tolerate getting it backwards
unless( defined $variable and ref($variable) eq 'SCALAR') {
require Carp;
Carp::croak("Usage:\n use Pod::Simple::Debug (NUMVAL)\nor"
. "\n use Pod::Simple::Debug (\\\$var, STARTNUMVAL)\nAborting");
}
} else {
require Carp;
Carp::croak("Usage:\n use Pod::Simple::Debug (NUMVAL)\nor"
. "\n use Pod::Simple::Debug (\\\$var, STARTNUMVAL)\nAborting");
}
if( defined &Pod::Simple::DEBUG ) {
require Carp;
Carp::croak("It's too late to call Pod::Simple::Debug -- "
. "Pod::Simple has already loaded\nAborting");
}
$value = 0 unless defined $value;
unless($value =~ m/^-?\d+$/) {
require Carp;
Carp::croak( "$value isn't a numeric value."
. "\nUsage:\n use Pod::Simple::Debug (NUMVAL)\nor"
. "\n use Pod::Simple::Debug (\\\$var, STARTNUMVAL)\nAborting");
}
if( defined $variable ) {
# make a not-really-constant
*Pod::Simple::DEBUG = sub () { $$variable } ;
$$variable = $value;
print "# Starting Pod::Simple::DEBUG = non-constant $variable with val $value\n";
} else {
*Pod::Simple::DEBUG = eval " sub () { $value } ";
print "# Starting Pod::Simple::DEBUG = $value\n";
}
require Pod::Simple;
return;
}
1;
__END__
=head1 NAME
Pod::Simple::Debug -- put Pod::Simple into trace/debug mode
=head1 SYNOPSIS
use Pod::Simple::Debug (5); # or some integer
Or:
my $debuglevel;
use Pod::Simple::Debug (\$debuglevel, 0);
...some stuff that uses Pod::Simple to do stuff, but which
you don't want debug output from...
$debug_level = 4;
...some stuff that uses Pod::Simple to do stuff, but which
you DO want debug output from...
$debug_level = 0;
=head1 DESCRIPTION
This is an internal module for controlling the debug level (a.k.a. trace
level) of Pod::Simple. This is of interest only to Pod::Simple
developers.
=head1 CAVEATS
Note that you should load this module I<before> loading Pod::Simple (or
any Pod::Simple-based class). If you try loading Pod::Simple::Debug
after &Pod::Simple::DEBUG is already defined, Pod::Simple::Debug will
throw a fatal error to the effect that
"it's s too late to call Pod::Simple::Debug".
Note that the C<use Pod::Simple::Debug (\$x, I<somenum>)> mode will make
Pod::Simple (et al) run rather slower, since &Pod::Simple::DEBUG won't
be a constant sub anymore, and so Pod::Simple (et al) won't compile with
constant-folding.
=head1 GUTS
Doing this:
use Pod::Simple::Debug (5); # or some integer
is basically equivalent to:
BEGIN { sub Pod::Simple::DEBUG () {5} } # or some integer
use Pod::Simple ();
And this:
use Pod::Simple::Debug (\$debug_level,0); # or some integer
is basically equivalent to this:
my $debug_level;
BEGIN { $debug_level = 0 }
BEGIN { sub Pod::Simple::DEBUG () { $debug_level }
use Pod::Simple ();
=head1 SEE ALSO
L<Pod::Simple>
The article "Constants in Perl", in I<The Perl Journal> issue
21. See L<http://www.sysadminmag.com/tpj/issues/vol5_5/>
=head1 COPYRIGHT AND DISCLAIMERS
Copyright (c) 2002 Sean M. Burke. All rights reserved.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
This program is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.
=head1 AUTHOR
Sean M. Burke C<sburke@cpan.org>
=cut
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