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sub _do_warn {
    local $SIG{'__WARN__'} = 'DEFAULT';
    
    my $msg = join '', @_;
    $msg =~ s/ at (.+?) line (\d+)\.$//;
    $stderr .= $msg;
    $stderr .= "\n" if substr($msg, -1, 1) ne "\n";
    
    _stack_trace($1, $2);
    
    print STDERR $stderr;
    $stderr = '';
    $in_eval = 0;
}


# 
# _do_die()
# -------
sub _do_die {
    local $SIG{'__WARN__'} = 'DEFAULT';
    local $SIG{'__DIE__' } = 'DEFAULT';
    
    CORE::die @_ if ref $_[0] and not $options{showrefs};
    CORE::die @_ if index($_[0], "\n\tat ") >= 0;
    my @args = @_;
    
    _use_data_dumper() if ref $args[0];
    my $msg = join '', map { ref $_ ? "Caught exception object: $_\: ".Dumper($_) : $_ } @args;
    $msg =~ s/ at (.+?) line (\d+)\.$//;
    $stderr .= $msg;
    $stderr .= "\n" if substr($msg, -1, 1) ne "\n";
    
    _stack_trace($1, $2);
    
    if($in_eval) {
        $@ = $stderr;
        $stderr = '';
        $in_eval = 0;
        CORE::die $@
        
    } else {
        print STDERR $stderr;
        $stderr = '';
        exit -1
    }
}


# 
# _stack_trace()
# ------------
sub _stack_trace {
    my($file,$line) = @_;
    $file ||= '';  $line ||= '';
    $file =~ '(eval \d+)' and $file = '<eval>';
    
    my $level = 2;
    my @stack = ( ['', $file, $line] );  # @stack = ( [ function, file, line ], ... )
    
    while(my @context = caller($level++)) {
        $context[1] ||= '';  $context[2] ||= '';
        $context[1] =~ '(eval \d+)' and $context[1] = '<eval>' and $in_eval = 1;
        $context[3] eq '(eval)' and $context[3] = '<eval>' and $in_eval = 1;
        $stack[-1][0] = $context[3];
        push @stack, [ '', @context[1, 2] ];
    }
    $stack[-1][0] = (caller($level-2))[0].'::' || 'main::';
    
    for my $func (@stack) {
        $$func[1] eq '' and $$func[1] = 'unknown source';
        $$func[2] and $$func[1] .= ':';
        $stderr .= "\tat $$func[0]($$func[1]$$func[2])\n";
    }
}


1;

__END__

=head1 NAME

Acme::JavaTrace - Module for using Java-like stack traces

=head1 VERSION

Version 0.08

=head1 SYNOPSIS

On the command-line:

    perl -wMAcme::JavaTrace program_with_strange_errors.pl

Inside a module:

    use Acme::JavaTrace;
    warn "some kind of non-fatal exception occured";
    die "some kind of fatal exception occured";


=head1 DESCRIPTION

C<< <buzzword> >>This module tries to improves the Perl programmer 
experience by porting the Java paradigm to print stack traces, which 
is more professional than Perl's way. C<< </buzzword> >>

This is achieved by modifying the functions C<warn()> and C<die()> 
in order to replace the standard messages by complete stack traces 
that precisely indicates how and where the error or warning occurred. 
Other than this, their use should stay unchanged, even when using 
C<die()> inside C<eval()>. 

For a explanation of why I wrote this module, you can read the slides 
of my lightning talk I<Entreprise Perl>, available here: 
L<http://maddingue.org/conferences/yapc-eu-2004/entreprise-perl/>


=head1 OPTIONS

Options can be set at import time using: 

    perl -wMDevel::SimpleTrace=option1,option2

or 

    use Devel::SimpleTrace qw(option1 option2);