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900,"def next(self, *expectation, **kwargs):
""""""
Parses the next token from the input and returns it. The new token can be
accessed from the #token attribute after the method was called.
If one or more arguments are specified, they must be rule names that are to
be expected at the current position. They will be attempted to be matched
first (in the specicied order). If the expectation could not be met, an
#UnexpectedTokenError is raised.
An expected Token will not be skipped, even if its rule defines it so.
# Arguments
expectation (str): The name of one or more rules that are expected from the
current position of the parser. If empty, the first matching token of ALL
rules will be returned. In this case, skippable tokens will be skipped.
as_accept (bool): If passed True, this method behaves the same as the
#accept() method. The default value is #False.
weighted (bool): If passed True, the tokens specified with *expectations*
are checked first, effectively giving them a higher priority than other
they would have from the order in the #rules list. The default value is
#False.
# Raises
ValueError: if an expectation doesn't match with a rule name.
UnexpectedTokenError: Ff an expectation is given and the expectation
wasn't fulfilled. Only when *as_accept* is set to #False.
TokenizationError: if a token could not be generated from the current
position of the Scanner.
""""""
as_accept = kwargs.pop('as_accept', False)
weighted = kwargs.pop('weighted', False)
for key in kwargs:
raise TypeError('unexpected keyword argument {0!r}'.format(key))
if self.token and self.token.type == eof:
if not as_accept and expectation and eof not in expectation:
raise UnexpectedTokenError(expectation, self.token)
elif as_accept and eof in expectation:
return self.token
elif as_accept:
return None
return self.token
token = None
while token is None:
# Stop if we reached the end of the input.
cursor = self.scanner.cursor
if not self.scanner:
token = Token(eof, cursor, None, None)
break
value = None
# Try to match the expected tokens.
if weighted:
for rule_name in expectation:
if rule_name == eof:
continue
rules = self.rules_map.get(rule_name)
if rules is None:
raise ValueError('unknown rule', rule_name)
for rule in rules:
value = rule.tokenize(self.scanner)
if value:
break
if value:
break
self.scanner.restore(cursor)
# Match the rest of the rules, but only if we're not acting
# like the accept() method that doesn't need the next token
# for raising an UnexpectedTokenError.
if not value:
if as_accept and weighted:
# Check only skippable rules if we're only trying to accept
# a certain token type and may consume any skippable tokens
# until then.
check_rules = self.skippable_rules
else:
check_rules = self.rules
for rule in check_rules:
if weighted and expectation and rule.name in expectation:
# Skip rules that we already tried.
continue
value = rule.tokenize(self.scanner)
if value:
break
self.scanner.restore(cursor)
if not value:
if as_accept:
return None
token = Token(None, cursor, self.scanner.char, None)
else:
assert rule, ""we should have a rule by now""
if type(value) is not Token:
if isinstance(value, tuple):
value, string_repr = value