#!/usr/bin/perl

use strict;

$SIG{__DIE__} = sub {
    if(my ($d) = $_[0] =~ /line (\d+)/) {
        seek DATA,0,0;
        while(<DATA>) {
            if($. == $d) {
                warn '> '.$..' '.$_;
            } else {
                warn '  '.$..' '.$_ if ($. > $d - 4) && ($. < $d + 4);
            }
        } 
    } 
};

my $foo = 'bar';

blah($foo);
learn('nothing');
sub blah (\[&]) {
    warn "don't talk nonsense";
    $_[0]->();
} 
sub learn {
    my $self->teach(shift);
    warn "got it";
} 
__END__