function varargout = spm_get_defaults(defstr, varargin)
% Get/set the defaults values associated with an identifier
% FORMAT defaults = spm_get_defaults
% Return the global "defaults" variable defined in spm_defaults.m.
%
% FORMAT defval = spm_get_defaults(defstr)
% Return the defaults value associated with identifier "defstr". 
% Currently, this is a '.' subscript reference into the global  
% "defaults" variable defined in spm_defaults.m.
%
% FORMAT spm_get_defaults(defstr, defval)
% Set the defaults value associated with identifier "defstr" to defval.
% The new defaults value applies immediately to:
% * new modules in batch jobs
% * modules in batch jobs that have not been saved yet
% This value will not be saved for future sessions of SPM. To make
% persistent changes, see help section in spm_defaults.m.
%__________________________________________________________________________
% Copyright (C) 2008-2014 Wellcome Trust Centre for Neuroimaging

% Volkmar Glauche
% $Id: spm_get_defaults.m 6157 2014-09-05 18:17:54Z guillaume $


global defaults;

if isempty(defaults)
    spm_defaults;
end

if nargin == 0
    varargout{1} = defaults;
    return
end

% construct subscript reference struct from dot delimited tag string
tags = textscan(defstr,'%s', 'delimiter','.');
subs = struct('type','.','subs',tags{1}');

if nargin == 1
    varargout{1} = subsref(defaults, subs);
else
    defaults = subsasgn(defaults, subs, varargin{1});
end