Python ast.operator() Examples

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _check_string_concat(
        self,
        left: ast.AST,
        op: ast.operator,
        right: Optional[ast.AST] = None,
    ) -> None:
        if not isinstance(op, ast.Add):
            return

        left_line = getattr(left, 'lineno', 0)
        if left_line != getattr(right, 'lineno', left_line):
            # By default we treat nodes that do not have lineno
            # as nodes on the same line.
            return

        for node in (left, right):
            if isinstance(node, self._string_nodes):
                self.add_violation(
                    consistency.ExplicitStringConcatViolation(node),
                )
                return 

def _check_useless_math_operator(
        self,
        op: ast.operator,
        left: Optional[ast.AST],
        right: Optional[ast.AST] = None,
    ) -> None:
        if isinstance(left, ast.Num) and left.n in self._left_special_cases:
            if right and isinstance(op, self._left_special_cases[left.n]):
                left = None

        non_negative_numbers = self._get_non_negative_nodes(left, right)

        for number in non_negative_numbers:
            forbidden = self._meaningless_operations.get(number.n, None)
            if forbidden and isinstance(op, forbidden):
                self.add_violation(
                    consistency.MeaninglessNumberOperationViolation(number),
                ) 

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _rewrite_assign(tok):
    """Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    Parameters
    ----------
    tok : tuple of int, str
        ints correspond to the all caps constants in the tokenize module

    Returns
    -------
    t : tuple of int, str
        Either the input or token or the replacement values
    """
    toknum, tokval = tok
    return toknum, '==' if tokval == '=' else tokval 

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _rewrite_assign(tok):
    """Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    Parameters
    ----------
    tok : tuple of int, str
        ints correspond to the all caps constants in the tokenize module

    Returns
    -------
    t : tuple of int, str
        Either the input or token or the replacement values
    """
    toknum, tokval = tok
    return toknum, '==' if tokval == '=' else tokval 

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _rewrite_assign(tok):
    """Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    Parameters
    ----------
    tok : tuple of int, str
        ints correspond to the all caps constants in the tokenize module

    Returns
    -------
    t : tuple of int, str
        Either the input or token or the replacement values
    """
    toknum, tokval = tok
    return toknum, '==' if tokval == '=' else tokval 

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _rewrite_assign(tok):
    """Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    Parameters
    ----------
    tok : tuple of int, str
        ints correspond to the all caps constants in the tokenize module

    Returns
    -------
    t : tuple of int, str
        Either the input or token or the replacement values
    """
    toknum, tokval = tok
    return toknum, '==' if tokval == '=' else tokval 

def _op_maker(op_class, op_symbol):
    """Return a function to create an op class with its symbol already passed.

    Returns
    -------
    f : callable
    """

    def f(self, node, *args, **kwargs):
        """Return a partial function with an Op subclass with an operator
        already passed.

        Returns
        -------
        f : callable
        """
        return partial(op_class, op_symbol, *args, **kwargs)
    return f 

def _rewrite_assign(tok):
    """Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    Parameters
    ----------
    tok : tuple of int, str
        ints correspond to the all caps constants in the tokenize module

    Returns
    -------
    t : tuple of int, str
        Either the input or token or the replacement values
    """
    toknum, tokval = tok
    return toknum, '==' if tokval == '=' else tokval 

def visit_NamedExpr(
        self,
        node: NamedExpr,
    ) -> None:  # pragma: py-lt-38
        """
        Disallows walrus ``:=`` operator.

        Raises:
            WalrusViolation

        """
        self.add_violation(consistency.WalrusViolation(node))
        self.generic_visit(node) 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                self.env.remove_tmp(right.name)
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                self.env.remove_tmp(left.name)
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _check_negation(self, op: ast.operator, right: ast.AST) -> None:
        is_double_minus = (
            isinstance(op, (ast.Add, ast.Sub)) and
            isinstance(right, ast.UnaryOp) and
            isinstance(right.op, ast.USub)
        )
        if is_double_minus:
            self.add_violation(
                consistency.OperationSignNegationViolation(right),
            ) 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _check_zero_division(self, op: ast.operator, number: ast.AST) -> None:
        number = unwrap_unary_node(number)

        is_zero_division = (
            isinstance(op, self._zero_divisors) and
            isinstance(number, ast.Num) and
            number.n == 0
        )
        if is_zero_division:
            self.add_violation(consistency.ZeroDivisionViolation(number)) 

def visit_Compare(self, node: ast.Compare) -> Any:
        if len(node.ops) > 1:
            raise ParseException('chained comparisons are not supported')

        op_type = type(node.ops[0])
        if op_type not in ExpressionParser.NODE_TO_COMPOP:
            raise ParseException(
                f'comparison operator {op_type.__name__} not allowed in expressions'
            )

        op_callable = ExpressionParser.NODE_TO_COMPOP[op_type]
        return op_callable(self.visit(node.left), self.visit(node.comparators[0])) 

def visit_BinOp(self, node: ast.BinOp) -> Any:
        op_type = type(node.op)
        if op_type not in ExpressionParser.NODE_TO_BINOP:
            raise ParseException(
                f'binary operator {op_type.__name__} not allowed in expressions'
            )

        op_callable = ExpressionParser.NODE_TO_BINOP[op_type]
        return op_callable(self.visit(node.left), self.visit(node.right)) 

def visit_UnaryOp(self, node: ast.UnaryOp) -> Any:
        op_type = type(node.op)
        if op_type not in ExpressionParser.NODE_TO_UNOP:
            raise ParseException(
                f'unary operator {op_type.__name__} not allowed in expressions'
            )

        op_callable = ExpressionParser.NODE_TO_UNOP[op_type]
        return op_callable(self.visit(node.operand)) 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _rewrite_membership_op(self, node, left, right):
        # the kind of the operator (is actually an instance)
        op_instance = node.op
        op_type = type(op_instance)

        # must be two terms and the comparison operator must be ==/!=/in/not in
        if is_term(left) and is_term(right) and op_type in self.rewrite_map:

            left_list, right_list = map(_is_list, (left, right))
            left_str, right_str = map(_is_str, (left, right))

            # if there are any strings or lists in the expression
            if left_list or right_list or left_str or right_str:
                op_instance = self.rewrite_map[op_type]()

            # pop the string variable out of locals and replace it with a list
            # of one string, kind of a hack
            if right_str:
                name = self.env.add_tmp([right.value])
                right = self.term_type(name, self.env)

            if left_str:
                name = self.env.add_tmp([left.value])
                left = self.term_type(name, self.env)

        op = self.visit(op_instance)
        return op, op_instance, left, right 

def _rewrite_assign(source):
    """Rewrite the assignment operator for PyTables expression that want to use
    ``=`` as a substitute for ``==``.
    """
    res = []
    g = tokenize.generate_tokens(StringIO(source).readline)
    for toknum, tokval, _, _, _ in g:
        res.append((toknum, '==' if tokval == '=' else tokval))
    return tokenize.untokenize(res) 

def __init__(self, gbls=None, lcls=None, level=1, resolvers=None,
                 target=None):
        self.level = level
        self.resolvers = tuple(resolvers or [])
        self.globals = dict()
        self.locals = dict()
        self.target = target
        self.ntemps = 1  # number of temporary variables in this scope

        if isinstance(lcls, Scope):
            ld, lcls = lcls, dict()
            self.locals.update(ld.locals.copy())
            self.globals.update(ld.globals.copy())
            self.resolvers += ld.resolvers
            if ld.target is not None:
                self.target = ld.target
            self.update(ld.level)

        frame = sys._getframe(level)
        try:
            self.globals.update(gbls or frame.f_globals)
            self.locals.update(lcls or frame.f_locals)
        finally:
            del frame

        # add some useful defaults
        self.globals['Timestamp'] = pd.lib.Timestamp
        self.globals['datetime'] = datetime

        # SUCH a hack
        self.globals['True'] = True
        self.globals['False'] = False

        # function defs
        self.globals['list'] = list
        self.globals['tuple'] = tuple

        res_keys = (list(o.keys()) for o in self.resolvers)
        self.resolver_keys = frozenset(reduce(operator.add, res_keys, []))
        self._global_resolvers = self.resolvers + (self.locals, self.globals)
        self._resolver = None

        self.resolver_dict = {}
        for o in self.resolvers:
            self.resolver_dict.update(dict(o))