def file_ref(self):
from metatab.util import slugify<EOL>assert self.file_name is None or isinstance(self.file_name, str)<EOL>if self.file_name is not None and self.row is not None:<EOL><INDENT>parts = split(self.file_name);<EOL>return "<STR_LIT>".format(parts[-<NUM_LIT:1>], self.row, self.col)<EOL><DEDENT>elif self.row is not None:<EOL><INDENT>return "<STR_LIT>".format(self.row, self.col)<EOL><DEDENT>else:<EOL><INDENT>return '<STR_LIT>'<EOL><DEDENT>
Return a string for the file, row and column of the term.