Sooner or later, every plugin developers will likely want to store user data. Since Typesetter doesn't use a database, saving and retrieving data is easily accomplished with two functions.

global $addonPathData;
$file = $addonPathData.'/data.php';

//saving data
$data = array('your'=>'array','of'=>'data'); 
if( !gpFiles::SaveData($file, 'data', $data) ){
	//... warn user data didn't save
}


//retrieve stored data
$data = gpFiles::Get($file,'data');

SaveData() and Get() are both available as of Typesetter 4.4