interactive Chart::Gnuplot

  # interactive gnuplot terminal
  use Hook::LexWrap;
  wrap 'Chart::Gnuplot::_execute',
      pre  => sub { my ( $self ) = @_;

                  # if this isn't an x11 terminal, there's nothing to do
                  return unless $self->{terminal} eq "x11";

                  # add 'pause' command to script to keep image from immediately disappearing
                  open(GPH, ">>$self->{_script}") || confess("Can't write $self->{_script}");
                  print GPH "\npause mouse button1\n";
                  close(GPH);

                  # output is not a file, delete the 'output' param or we'll get an error in _execute
                  delete $self->{output};
              };