def _parse_and(self, tokens):
# Handle "... and ... and ..."
lexpr = self._parse_not(tokens)
if tokens and tokens[0] == 'and':
tokens.pop(0)
rexpr = self._parse_and(tokens) # recurs
return ExpressionOperator(operator.and_, lexpr, rexpr)
else:
return lexpr
def _parse(self, tokens):
# Operator precedence: or, and, not, <, <=, >, >=, <>, !=, ==
# so we start with parsing " ... or .. or .." and decent from there
lexpr = self._parse_and(tokens)
if tokens and tokens[0] == 'or':
tokens.pop(0)
rexpr = self._parse(tokens) # recurs
return ExpressionOperator(operator.or_, lexpr, rexpr)
else:
return lexpr
def _parse_comparison(self, tokens):
# Handle "... op ..." where op is: <, <=, >, >=, <>, !=, ==
lexpr = self._parse_statement(tokens)
if tokens and tokens[0] in self.operators \
and tokens[0] not in ('or', 'and', 'not'):
op = tokens.pop(0)
rexpr = self._parse_statement(tokens)
return ExpressionOperator(self.operators[op], lexpr, rexpr)
else:
return lexpr