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: gmt_gallery.m
    path of file: ./repos/gmtmex/src
    
    the code of the file until where you have to start completion: function  [ps_, t_path_] = gmt_gallery(varargin)

    
function  [ps_, t_path_] = gmt_gallery(varargin)
%	The examples Gallery in GMT-MEX API
%
% gmt_gallery(OPT, R_DIR, O_PATH, VERBOSE)
% or
% [ps_, t_path_] = gmt_gallery(OPT, R_DIR, O_PATH, VERBOSE)
%
% If R_DIR and O_PATH are not transmitted, the defaul value in this function is used (JL paths)
% R_DIR is a string with the path to the root of your GMT installation. E.g.
%	R_DIR = 'C:/progs_cygw/GMTdev/gmt6/'
%
% O_PATH is a string with the output path where the new PS files will be writen
%
% If only R_DIR is set than O_PATH will default to current directory
%
% If the last argin is a logical variable that the examples are run in verbose mode
%
% Examples:
%	gmt_gallery([], true)           Run all examples in verbose mode and use GMT_{ROOT|PLOT}_DIR paths
%	gmt_gallery('ex03', true)       Run example3 in verbose mode and use GMT_{ROOT|PLOT}_DIR paths
%	gmt_gallery([], '/user/PW_GMT_location/', true)	Run all examples in verbose mode and set GMT_ROOT_DIR location

%	$Id$

	global GMT_ROOT_DIR GMT_PLOT_DIR
	if (~exist('GMT_ROOT_DIR', 'var') || isempty(GMT_ROOT_DIR))
		GMT_ROOT_DIR = 'C:/progs_cygw/GMTdev/gmt5/trunk/';
		GMT_PLOT_DIR = 'V:/';		% Set this if you want to save the PS files in a prticular place
	end