This function loads the package specified by package from the file filename if not already loaded. If filename is not specified, the list of directories specified in the set loadpath command option is searched for a file named package.acl, where .acl is the Arbortext Command Language file name suffix. Returns 1 (True) if the package was loaded or 0 (False) if the package file could not be opened or if the specified package is not defined after the file is read.