def _followups(self, nonterm):
"""Return the set of token types that could follow the given
nonterminal."""
res = {}
for nonterm2, symb in self._parse_table.keys():
if nonterm == nonterm2:
set_add(res, symb)
return seq_sorted([Token.type_description(key) for key in res.keys()])
def parse_error(self, top, _previous_token, token):
"Raises a ParserException describing a parse error."
if is_nonterminal(top):
follow = self._followups(top)
else:
follow = [Token.type_description(top)]
if len(follow) == 1:
msg = i18n.i18n('Found: %s\nExpected: %s') % (token, follow[0])
else:
msg = ''
msg += i18n.i18n('\n'.join([
'Found: %s',
'Expected one of the following tokens:'])) % (
token,)
msg += '\n' + utils.indent('\n'.join(follow))
raise ParserException(msg, position.ProgramAreaNear(token))
