You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: read_nex_event.m
    path of file: ./repos/spm12/external/fieldtrip/fileio/private
    
    the code of the file until where you have to start completion: function [event] = read_nex_event(filename)

% READ_NEX_EVENT for Plexon *.nex file, supports NEX variable types:
%   marker, interval, and event
%
% Use as
%   [event] = read_nex_event(filename)
%
% The event.type used to select events in ft_trialfun_general is the
% variable name from the NEX file (hdr.varheader.name - not to be confused
% with hdr.varheader.type).
%
% The sample numbers returned in event.sample correspond with the

    
function [event] = read_nex_event(filename)

% READ_NEX_EVENT for Plexon *.nex file, supports NEX variable types:
%   marker, interval, and event
%
% Use as
%   [event] = read_nex_event(filename)
%
% The event.type used to select events in ft_trialfun_general is the
% variable name from the NEX file (hdr.varheader.name - not to be confused
% with hdr.varheader.type).
%
% The sample numbers returned in event.sample correspond with the
% timestamps, correcting for the difference in sampling frequency in the
% continuous LFP channels and the system sampling frequency. Assuming 40kHz
% sampling frequency for the system and 1kHz for the LFP channels, it is
%   event.sample = timestamp / (40000/1000);
% If there are no continuous variables in the file, the system sampling
% frequency is used throughout, so
%   event.sample = timestamp;
%
% See also READ_NEX_HEADER, READ_NEX_DATA

% Copyright (C) 2005-2007, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip 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.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id$

hdr = read_nex_header(filename);
adindx = find(cell2mat({hdr.varheader.typ})==5);
if isempty(adindx)  % this would otherwise produce an error
  ft_warning('No continuous variables found - using hdr.filheader.frequency');
  smpfrq = hdr.filheader.frequency;
else
  smpfrq = hdr.varheader(adindx(1)).wfrequency;
end