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: generator.m
    path of file: ./repos/spinw/swfiles/+swsym
    
    the code of the file until where you have to start completion: function [symOp, symInfo] = generator(sym, fid0)
% returns symmetry operators of a given space group
% 
% ### Syntax
% 
% `[symOp, symInfo] = swsym.generator(sym)`
% 
% `[symOp, symInfo] = swsym.generator(sym,fid)`
%
% ### Description
% 
% `[symOp, symInfo] = swsym.generator(sym)` gives the symmetry operators
% based on a given space group number or a string of symmetry operators.
% Without arguments, the function returns the name of all space groups
% stored in [symmetry.dat] file.
%  
% `[symOp, symInfo] = swsym.generator(sym,fid)` also prints the symmetry
% operators to the file identified by `fid`.
%
% ### Input Arguments
% 
% `sym`
% : Either the label of the space group or the index from
%   the [International Tables of Crystallography](http://it.iucr.org/A/) or
%   string containing the space group operators in the same format as used
%   in the [symmetry.dat] file (for details see [swsym.str]).
% 
% `fid`
% : If non-zero, the symmetry operators will be printed to the file
%   identified by `fid`, the following values are valid:
%   * `0`   no printed output (default),
%   * `1`   standard output (Command Line),
%   * `fid` text file opened before using `fid = fopen(path)`.
% 

    
function [symOp, symInfo] = generator(sym, fid0)
% returns symmetry operators of a given space group
% 
% ### Syntax
% 
% `[symOp, symInfo] = swsym.generator(sym)`
% 
% `[symOp, symInfo] = swsym.generator(sym,fid)`
%
% ### Description
% 
% `[symOp, symInfo] = swsym.generator(sym)` gives the symmetry operators
% based on a given space group number or a string of symmetry operators.
% Without arguments, the function returns the name of all space groups
% stored in [symmetry.dat] file.
%  
% `[symOp, symInfo] = swsym.generator(sym,fid)` also prints the symmetry
% operators to the file identified by `fid`.
%
% ### Input Arguments
% 
% `sym`
% : Either the label of the space group or the index from
%   the [International Tables of Crystallography](http://it.iucr.org/A/) or
%   string containing the space group operators in the same format as used
%   in the [symmetry.dat] file (for details see [swsym.str]).
% 
% `fid`
% : If non-zero, the symmetry operators will be printed to the file
%   identified by `fid`, the following values are valid:
%   * `0`   no printed output (default),
%   * `1`   standard output (Command Line),
%   * `fid` text file opened before using `fid = fopen(path)`.
% 
% ### Output Arguments
% 
% `symOp`
% : Symmetry operators in a matrix with dimensions of $[3\times 4\times
%   n_{op}]$.
%
% `symInfo`
% : Structure that contains additional information about the space 
%   group with the following fields:
%   * `name`    Name of the space group, if the `swsym.generator`
%               function is called with no input, name stores the name of
%               all space groups from [symmetry.dat] file in a cell.
%   * `str`     The string of the symmetry operations.
%   * `num`     The line index in the [symmetry.dat] file.
% 
% ### See Also
% 
% [swsym.add] \| [spinw] \| [spinw.gencoupling] \| [swsym.position]
%

symInfo = struct('name','','str','','num',-1);

if nargin < 2
    fid0 = 0;
end