my @holdem;
my %dispatch = ( one => \&subone, two => \&subtwo );
my $target;

open( $pipe, "-|", "ls" );
while ( <$pipe> ) {
    if ( $target ) {
        $target->( $_ );
    }
    else {
        push @holdem, $_;
        my $decision = look_for_evidence( $_ );
        if ( $decision =~ /one|two/ ) {
            $target = $dispatch{$decision};
            $target->( $_ ) for ( @holdem );
        }
    }
}