@meta.hook(EBNF, "<STR_LIT>")<EOL>def add_mod(self, seq, mod):
modstr = self.value(mod)<EOL>if modstr == '<STR_LIT>':<EOL><INDENT>seq.parser_tree = parsing.Complement(seq.parser_tree)<EOL><DEDENT>elif modstr == '<STR_LIT>':<EOL><INDENT>seq.parser_tree = parsing.LookAhead(seq.parser_tree)<EOL><DEDENT>elif modstr == '<STR_LIT:!>':<EOL><INDENT>seq.parser_tree = parsing.Neg(seq.parser_tree)<EOL><DEDENT>elif modstr == '<STR_LIT>':<EOL><INDENT>seq.parser_tree = parsing.Until(seq.parser_tree)<EOL><DEDENT>return True<EOL>
Create a tree.{Complement, LookAhead, Neg, Until}