function [dataout] = ft_examplefunction(cfg, datain)

% FT_EXAMPLEFUNCTION demonstrates to new developers how a FieldTrip function should look like

%

% Use as

% outdata = ft_examplefunction(cfg, indata)

% where indata is <<describe the type of data or where it comes from>>

% and cfg is a configuration structure that should contain

%

% <<note that the cfg list should be indented with two spaces

%

% cfg.option1 = value, explain the value here (default = something)

% cfg.option2 = value, describe the value here and if needed

% continue here to allow automatic parsing of the help

%

% The configuration can optionally contain

% cfg.option3 = value, explain it here (default is automatic)

%

% To facilitate data-handling and distributed computing you can use

% cfg.inputfile = ...

% cfg.outputfile = ...

% If you specify one of these (or both) the input data will be read from a *.mat

% file on disk and/or the output data will be written to a *.mat file. These mat

% files should contain only a single variable, corresponding with the

% input/output structure.

%

% See also <<give a list of function names, all in capitals>>

% Here come the Copyrights

%

% Here comes the Revision tag, which is auto-updated by the version control system

% $Id$

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% the initial part deals with parsing the input options and data

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% these are used by the ft_preamble/ft_postamble function and scripts

ft_revision = '$Id$';

ft_nargin = nargin;

ft_nargout = nargout;

% do the general setup of the function

% the ft_preamble function works by calling a number of scripts from

% fieldtrip/utility/private that are able to modify the local workspace

ft_defaults % this ensures that the path is correct and that the ft_defaults global variable is available

ft_preamble init % this will reset ft_warning and show the function help if nargin==0 and return an error

ft_preamble debug % this allows for displaying or saving the function name and input arguments upon an error

ft_preamble loadvar datain % this reads the input data in case the user specified the cfg.inputfile option

ft_preamble provenance datain % this records the time and memory usage at the beginning of the function

% the ft_abort variable is set to true or false in ft_preamble_init

if ft_abort

% do not continue function execution in case the outputfile is present and the user indicated to keep it

return

end

% ensure that the input data is valid for this function, this will also do

% backward-compatibility conversions of old data that for example was

% read from an old *.mat file

datain = ft_checkdata(datain, 'datatype', {'raw+comp', 'raw'}, 'feedback', 'yes', 'hassampleinfo', 'yes');

% check if the input cfg is valid for this function

cfg = ft_checkconfig(cfg, 'deprecated', {'normalizecov', 'normalizevar'});

cfg = ft_checkconfig(cfg, 'renamed', {'blc', 'demean'});

cfg = ft_checkconfig(cfg, 'renamed', {'blcwindow', 'baselinewindow'});

% ensure that the required options are present

cfg = ft_checkconfig(cfg, 'required', {'method', 'foi', 'tapsmofrq'});

% ensure that the options are valid

cfg = ft_checkopt(cfg, 'vartrllen', 'double', {0, 1, 2});

cfg = ft_checkopt(cfg, 'method', 'char', {'mtm', 'convol'});

% check the user-supplied options or set the defaults

% store them in cfg, so that they end up in dataout.cfg

cfg.method = ft_getopt(cfg, 'method'); % there is no default, this wil be []

cfg.vartrllen = ft_getopt(cfg, 'vartrllen', 2); % the default is 2

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% the actual computation is done in the middle part

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% do your stuff...

dataout = [];

% this might involve more active checking of whether the input options

% are consistent with the data and with each other

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% deal with the output

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% do the general cleanup and bookkeeping at the end of the function

% the ft_postamble function works by calling a number of scripts from

% fieldtrip/utility/private that are able to modify the local workspace

ft_postamble debug % this clears the onCleanup function used for debugging in case of an error

ft_postamble previous datain % this copies the datain.cfg structure into the cfg.previous field. You can also use it for multiple inputs, or for "varargin"

ft_postamble provenance dataout % this records the time and memory at the end of the function, prints them on screen and adds this information together with the function name and MATLAB version etc. to the output cfg

ft_postamble history dataout % this adds the local cfg structure to the output data structure, i.e. dataout.cfg = cfg

ft_postamble savevar dataout % this saves the output data structure to disk in case the user specified the cfg.outputfile option