| # -*- coding: utf-8 -*- |
| """ |
| jinja2.nodes |
| ~~~~~~~~~~~~ |
| |
| This module implements additional nodes derived from the ast base node. |
| |
| It also provides some node tree helper functions like `in_lineno` and |
| `get_nodes` used by the parser and translator in order to normalize |
| python and jinja nodes. |
| |
| :copyright: (c) 2010 by the Jinja Team. |
| :license: BSD, see LICENSE for more details. |
| """ |
| import operator |
| |
| from collections import deque |
| from jinja2.utils import Markup |
| from jinja2._compat import next, izip, with_metaclass, text_type, \ |
| method_type, function_type |
| |
| |
| #: the types we support for context functions |
| _context_function_types = (function_type, method_type) |
| |
| |
| _binop_to_func = { |
| '*': operator.mul, |
| '/': operator.truediv, |
| '//': operator.floordiv, |
| '**': operator.pow, |
| '%': operator.mod, |
| '+': operator.add, |
| '-': operator.sub |
| } |
| |
| _uaop_to_func = { |
| 'not': operator.not_, |
| '+': operator.pos, |
| '-': operator.neg |
| } |
| |
| _cmpop_to_func = { |
| 'eq': operator.eq, |
| 'ne': operator.ne, |
| 'gt': operator.gt, |
| 'gteq': operator.ge, |
| 'lt': operator.lt, |
| 'lteq': operator.le, |
| 'in': lambda a, b: a in b, |
| 'notin': lambda a, b: a not in b |
| } |
| |
| |
| class Impossible(Exception): |
| """Raised if the node could not perform a requested action.""" |
| |
| |
| class NodeType(type): |
| """A metaclass for nodes that handles the field and attribute |
| inheritance. fields and attributes from the parent class are |
| automatically forwarded to the child.""" |
| |
| def __new__(cls, name, bases, d): |
| for attr in 'fields', 'attributes': |
| storage = [] |
| storage.extend(getattr(bases[0], attr, ())) |
| storage.extend(d.get(attr, ())) |
| assert len(bases) == 1, 'multiple inheritance not allowed' |
| assert len(storage) == len(set(storage)), 'layout conflict' |
| d[attr] = tuple(storage) |
| d.setdefault('abstract', False) |
| return type.__new__(cls, name, bases, d) |
| |
| |
| class EvalContext(object): |
| """Holds evaluation time information. Custom attributes can be attached |
| to it in extensions. |
| """ |
| |
| def __init__(self, environment, template_name=None): |
| self.environment = environment |
| if callable(environment.autoescape): |
| self.autoescape = environment.autoescape(template_name) |
| else: |
| self.autoescape = environment.autoescape |
| self.volatile = False |
| |
| def save(self): |
| return self.__dict__.copy() |
| |
| def revert(self, old): |
| self.__dict__.clear() |
| self.__dict__.update(old) |
| |
| |
| def get_eval_context(node, ctx): |
| if ctx is None: |
| if node.environment is None: |
| raise RuntimeError('if no eval context is passed, the ' |
| 'node must have an attached ' |
| 'environment.') |
| return EvalContext(node.environment) |
| return ctx |
| |
| |
| class Node(with_metaclass(NodeType, object)): |
| """Baseclass for all Jinja2 nodes. There are a number of nodes available |
| of different types. There are four major types: |
| |
| - :class:`Stmt`: statements |
| - :class:`Expr`: expressions |
| - :class:`Helper`: helper nodes |
| - :class:`Template`: the outermost wrapper node |
| |
| All nodes have fields and attributes. Fields may be other nodes, lists, |
| or arbitrary values. Fields are passed to the constructor as regular |
| positional arguments, attributes as keyword arguments. Each node has |
| two attributes: `lineno` (the line number of the node) and `environment`. |
| The `environment` attribute is set at the end of the parsing process for |
| all nodes automatically. |
| """ |
| fields = () |
| attributes = ('lineno', 'environment') |
| abstract = True |
| |
| def __init__(self, *fields, **attributes): |
| if self.abstract: |
| raise TypeError('abstract nodes are not instanciable') |
| if fields: |
| if len(fields) != len(self.fields): |
| if not self.fields: |
| raise TypeError('%r takes 0 arguments' % |
| self.__class__.__name__) |
| raise TypeError('%r takes 0 or %d argument%s' % ( |
| self.__class__.__name__, |
| len(self.fields), |
| len(self.fields) != 1 and 's' or '' |
| )) |
| for name, arg in izip(self.fields, fields): |
| setattr(self, name, arg) |
| for attr in self.attributes: |
| setattr(self, attr, attributes.pop(attr, None)) |
| if attributes: |
| raise TypeError('unknown attribute %r' % |
| next(iter(attributes))) |
| |
| def iter_fields(self, exclude=None, only=None): |
| """This method iterates over all fields that are defined and yields |
| ``(key, value)`` tuples. Per default all fields are returned, but |
| it's possible to limit that to some fields by providing the `only` |
| parameter or to exclude some using the `exclude` parameter. Both |
| should be sets or tuples of field names. |
| """ |
| for name in self.fields: |
| if (exclude is only is None) or \ |
| (exclude is not None and name not in exclude) or \ |
| (only is not None and name in only): |
| try: |
| yield name, getattr(self, name) |
| except AttributeError: |
| pass |
| |
| def iter_child_nodes(self, exclude=None, only=None): |
| """Iterates over all direct child nodes of the node. This iterates |
| over all fields and yields the values of they are nodes. If the value |
| of a field is a list all the nodes in that list are returned. |
| """ |
| for field, item in self.iter_fields(exclude, only): |
| if isinstance(item, list): |
| for n in item: |
| if isinstance(n, Node): |
| yield n |
| elif isinstance(item, Node): |
| yield item |
| |
| def find(self, node_type): |
| """Find the first node of a given type. If no such node exists the |
| return value is `None`. |
| """ |
| for result in self.find_all(node_type): |
| return result |
| |
| def find_all(self, node_type): |
| """Find all the nodes of a given type. If the type is a tuple, |
| the check is performed for any of the tuple items. |
| """ |
| for child in self.iter_child_nodes(): |
| if isinstance(child, node_type): |
| yield child |
| for result in child.find_all(node_type): |
| yield result |
| |
| def set_ctx(self, ctx): |
| """Reset the context of a node and all child nodes. Per default the |
| parser will all generate nodes that have a 'load' context as it's the |
| most common one. This method is used in the parser to set assignment |
| targets and other nodes to a store context. |
| """ |
| todo = deque([self]) |
| while todo: |
| node = todo.popleft() |
| if 'ctx' in node.fields: |
| node.ctx = ctx |
| todo.extend(node.iter_child_nodes()) |
| return self |
| |
| def set_lineno(self, lineno, override=False): |
| """Set the line numbers of the node and children.""" |
| todo = deque([self]) |
| while todo: |
| node = todo.popleft() |
| if 'lineno' in node.attributes: |
| if node.lineno is None or override: |
| node.lineno = lineno |
| todo.extend(node.iter_child_nodes()) |
| return self |
| |
| def set_environment(self, environment): |
| """Set the environment for all nodes.""" |
| todo = deque([self]) |
| while todo: |
| node = todo.popleft() |
| node.environment = environment |
| todo.extend(node.iter_child_nodes()) |
| return self |
| |
| def __eq__(self, other): |
| return type(self) is type(other) and \ |
| tuple(self.iter_fields()) == tuple(other.iter_fields()) |
| |
| def __ne__(self, other): |
| return not self.__eq__(other) |
| |
| # Restore Python 2 hashing behavior on Python 3 |
| __hash__ = object.__hash__ |
| |
| def __repr__(self): |
| return '%s(%s)' % ( |
| self.__class__.__name__, |
| ', '.join('%s=%r' % (arg, getattr(self, arg, None)) for |
| arg in self.fields) |
| ) |
| |
| |
| class Stmt(Node): |
| """Base node for all statements.""" |
| abstract = True |
| |
| |
| class Helper(Node): |
| """Nodes that exist in a specific context only.""" |
| abstract = True |
| |
| |
| class Template(Node): |
| """Node that represents a template. This must be the outermost node that |
| is passed to the compiler. |
| """ |
| fields = ('body',) |
| |
| |
| class Output(Stmt): |
| """A node that holds multiple expressions which are then printed out. |
| This is used both for the `print` statement and the regular template data. |
| """ |
| fields = ('nodes',) |
| |
| |
| class Extends(Stmt): |
| """Represents an extends statement.""" |
| fields = ('template',) |
| |
| |
| class For(Stmt): |
| """The for loop. `target` is the target for the iteration (usually a |
| :class:`Name` or :class:`Tuple`), `iter` the iterable. `body` is a list |
| of nodes that are used as loop-body, and `else_` a list of nodes for the |
| `else` block. If no else node exists it has to be an empty list. |
| |
| For filtered nodes an expression can be stored as `test`, otherwise `None`. |
| """ |
| fields = ('target', 'iter', 'body', 'else_', 'test', 'recursive') |
| |
| |
| class If(Stmt): |
| """If `test` is true, `body` is rendered, else `else_`.""" |
| fields = ('test', 'body', 'else_') |
| |
| |
| class Macro(Stmt): |
| """A macro definition. `name` is the name of the macro, `args` a list of |
| arguments and `defaults` a list of defaults if there are any. `body` is |
| a list of nodes for the macro body. |
| """ |
| fields = ('name', 'args', 'defaults', 'body') |
| |
| |
| class CallBlock(Stmt): |
| """Like a macro without a name but a call instead. `call` is called with |
| the unnamed macro as `caller` argument this node holds. |
| """ |
| fields = ('call', 'args', 'defaults', 'body') |
| |
| |
| class FilterBlock(Stmt): |
| """Node for filter sections.""" |
| fields = ('body', 'filter') |
| |
| |
| class Block(Stmt): |
| """A node that represents a block.""" |
| fields = ('name', 'body', 'scoped') |
| |
| |
| class Include(Stmt): |
| """A node that represents the include tag.""" |
| fields = ('template', 'with_context', 'ignore_missing') |
| |
| |
| class Import(Stmt): |
| """A node that represents the import tag.""" |
| fields = ('template', 'target', 'with_context') |
| |
| |
| class FromImport(Stmt): |
| """A node that represents the from import tag. It's important to not |
| pass unsafe names to the name attribute. The compiler translates the |
| attribute lookups directly into getattr calls and does *not* use the |
| subscript callback of the interface. As exported variables may not |
| start with double underscores (which the parser asserts) this is not a |
| problem for regular Jinja code, but if this node is used in an extension |
| extra care must be taken. |
| |
| The list of names may contain tuples if aliases are wanted. |
| """ |
| fields = ('template', 'names', 'with_context') |
| |
| |
| class ExprStmt(Stmt): |
| """A statement that evaluates an expression and discards the result.""" |
| fields = ('node',) |
| |
| |
| class Assign(Stmt): |
| """Assigns an expression to a target.""" |
| fields = ('target', 'node') |
| |
| |
| class Expr(Node): |
| """Baseclass for all expressions.""" |
| abstract = True |
| |
| def as_const(self, eval_ctx=None): |
| """Return the value of the expression as constant or raise |
| :exc:`Impossible` if this was not possible. |
| |
| An :class:`EvalContext` can be provided, if none is given |
| a default context is created which requires the nodes to have |
| an attached environment. |
| |
| .. versionchanged:: 2.4 |
| the `eval_ctx` parameter was added. |
| """ |
| raise Impossible() |
| |
| def can_assign(self): |
| """Check if it's possible to assign something to this node.""" |
| return False |
| |
| |
| class BinExpr(Expr): |
| """Baseclass for all binary expressions.""" |
| fields = ('left', 'right') |
| operator = None |
| abstract = True |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| # intercepted operators cannot be folded at compile time |
| if self.environment.sandboxed and \ |
| self.operator in self.environment.intercepted_binops: |
| raise Impossible() |
| f = _binop_to_func[self.operator] |
| try: |
| return f(self.left.as_const(eval_ctx), self.right.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| |
| |
| class UnaryExpr(Expr): |
| """Baseclass for all unary expressions.""" |
| fields = ('node',) |
| operator = None |
| abstract = True |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| # intercepted operators cannot be folded at compile time |
| if self.environment.sandboxed and \ |
| self.operator in self.environment.intercepted_unops: |
| raise Impossible() |
| f = _uaop_to_func[self.operator] |
| try: |
| return f(self.node.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| |
| |
| class Name(Expr): |
| """Looks up a name or stores a value in a name. |
| The `ctx` of the node can be one of the following values: |
| |
| - `store`: store a value in the name |
| - `load`: load that name |
| - `param`: like `store` but if the name was defined as function parameter. |
| """ |
| fields = ('name', 'ctx') |
| |
| def can_assign(self): |
| return self.name not in ('true', 'false', 'none', |
| 'True', 'False', 'None') |
| |
| |
| class Literal(Expr): |
| """Baseclass for literals.""" |
| abstract = True |
| |
| |
| class Const(Literal): |
| """All constant values. The parser will return this node for simple |
| constants such as ``42`` or ``"foo"`` but it can be used to store more |
| complex values such as lists too. Only constants with a safe |
| representation (objects where ``eval(repr(x)) == x`` is true). |
| """ |
| fields = ('value',) |
| |
| def as_const(self, eval_ctx=None): |
| return self.value |
| |
| @classmethod |
| def from_untrusted(cls, value, lineno=None, environment=None): |
| """Return a const object if the value is representable as |
| constant value in the generated code, otherwise it will raise |
| an `Impossible` exception. |
| """ |
| from .compiler import has_safe_repr |
| if not has_safe_repr(value): |
| raise Impossible() |
| return cls(value, lineno=lineno, environment=environment) |
| |
| |
| class TemplateData(Literal): |
| """A constant template string.""" |
| fields = ('data',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if eval_ctx.volatile: |
| raise Impossible() |
| if eval_ctx.autoescape: |
| return Markup(self.data) |
| return self.data |
| |
| |
| class Tuple(Literal): |
| """For loop unpacking and some other things like multiple arguments |
| for subscripts. Like for :class:`Name` `ctx` specifies if the tuple |
| is used for loading the names or storing. |
| """ |
| fields = ('items', 'ctx') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return tuple(x.as_const(eval_ctx) for x in self.items) |
| |
| def can_assign(self): |
| for item in self.items: |
| if not item.can_assign(): |
| return False |
| return True |
| |
| |
| class List(Literal): |
| """Any list literal such as ``[1, 2, 3]``""" |
| fields = ('items',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return [x.as_const(eval_ctx) for x in self.items] |
| |
| |
| class Dict(Literal): |
| """Any dict literal such as ``{1: 2, 3: 4}``. The items must be a list of |
| :class:`Pair` nodes. |
| """ |
| fields = ('items',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return dict(x.as_const(eval_ctx) for x in self.items) |
| |
| |
| class Pair(Helper): |
| """A key, value pair for dicts.""" |
| fields = ('key', 'value') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return self.key.as_const(eval_ctx), self.value.as_const(eval_ctx) |
| |
| |
| class Keyword(Helper): |
| """A key, value pair for keyword arguments where key is a string.""" |
| fields = ('key', 'value') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return self.key, self.value.as_const(eval_ctx) |
| |
| |
| class CondExpr(Expr): |
| """A conditional expression (inline if expression). (``{{ |
| foo if bar else baz }}``) |
| """ |
| fields = ('test', 'expr1', 'expr2') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if self.test.as_const(eval_ctx): |
| return self.expr1.as_const(eval_ctx) |
| |
| # if we evaluate to an undefined object, we better do that at runtime |
| if self.expr2 is None: |
| raise Impossible() |
| |
| return self.expr2.as_const(eval_ctx) |
| |
| |
| class Filter(Expr): |
| """This node applies a filter on an expression. `name` is the name of |
| the filter, the rest of the fields are the same as for :class:`Call`. |
| |
| If the `node` of a filter is `None` the contents of the last buffer are |
| filtered. Buffers are created by macros and filter blocks. |
| """ |
| fields = ('node', 'name', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if eval_ctx.volatile or self.node is None: |
| raise Impossible() |
| # we have to be careful here because we call filter_ below. |
| # if this variable would be called filter, 2to3 would wrap the |
| # call in a list beause it is assuming we are talking about the |
| # builtin filter function here which no longer returns a list in |
| # python 3. because of that, do not rename filter_ to filter! |
| filter_ = self.environment.filters.get(self.name) |
| if filter_ is None or getattr(filter_, 'contextfilter', False): |
| raise Impossible() |
| obj = self.node.as_const(eval_ctx) |
| args = [x.as_const(eval_ctx) for x in self.args] |
| if getattr(filter_, 'evalcontextfilter', False): |
| args.insert(0, eval_ctx) |
| elif getattr(filter_, 'environmentfilter', False): |
| args.insert(0, self.environment) |
| kwargs = dict(x.as_const(eval_ctx) for x in self.kwargs) |
| if self.dyn_args is not None: |
| try: |
| args.extend(self.dyn_args.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| if self.dyn_kwargs is not None: |
| try: |
| kwargs.update(self.dyn_kwargs.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| try: |
| return filter_(obj, *args, **kwargs) |
| except Exception: |
| raise Impossible() |
| |
| |
| class Test(Expr): |
| """Applies a test on an expression. `name` is the name of the test, the |
| rest of the fields are the same as for :class:`Call`. |
| """ |
| fields = ('node', 'name', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs') |
| |
| |
| class Call(Expr): |
| """Calls an expression. `args` is a list of arguments, `kwargs` a list |
| of keyword arguments (list of :class:`Keyword` nodes), and `dyn_args` |
| and `dyn_kwargs` has to be either `None` or a node that is used as |
| node for dynamic positional (``*args``) or keyword (``**kwargs``) |
| arguments. |
| """ |
| fields = ('node', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if eval_ctx.volatile: |
| raise Impossible() |
| obj = self.node.as_const(eval_ctx) |
| |
| # don't evaluate context functions |
| args = [x.as_const(eval_ctx) for x in self.args] |
| if isinstance(obj, _context_function_types): |
| if getattr(obj, 'contextfunction', False): |
| raise Impossible() |
| elif getattr(obj, 'evalcontextfunction', False): |
| args.insert(0, eval_ctx) |
| elif getattr(obj, 'environmentfunction', False): |
| args.insert(0, self.environment) |
| |
| kwargs = dict(x.as_const(eval_ctx) for x in self.kwargs) |
| if self.dyn_args is not None: |
| try: |
| args.extend(self.dyn_args.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| if self.dyn_kwargs is not None: |
| try: |
| kwargs.update(self.dyn_kwargs.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| try: |
| return obj(*args, **kwargs) |
| except Exception: |
| raise Impossible() |
| |
| |
| class Getitem(Expr): |
| """Get an attribute or item from an expression and prefer the item.""" |
| fields = ('node', 'arg', 'ctx') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if self.ctx != 'load': |
| raise Impossible() |
| try: |
| return self.environment.getitem(self.node.as_const(eval_ctx), |
| self.arg.as_const(eval_ctx)) |
| except Exception: |
| raise Impossible() |
| |
| def can_assign(self): |
| return False |
| |
| |
| class Getattr(Expr): |
| """Get an attribute or item from an expression that is a ascii-only |
| bytestring and prefer the attribute. |
| """ |
| fields = ('node', 'attr', 'ctx') |
| |
| def as_const(self, eval_ctx=None): |
| if self.ctx != 'load': |
| raise Impossible() |
| try: |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return self.environment.getattr(self.node.as_const(eval_ctx), |
| self.attr) |
| except Exception: |
| raise Impossible() |
| |
| def can_assign(self): |
| return False |
| |
| |
| class Slice(Expr): |
| """Represents a slice object. This must only be used as argument for |
| :class:`Subscript`. |
| """ |
| fields = ('start', 'stop', 'step') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| def const(obj): |
| if obj is None: |
| return None |
| return obj.as_const(eval_ctx) |
| return slice(const(self.start), const(self.stop), const(self.step)) |
| |
| |
| class Concat(Expr): |
| """Concatenates the list of expressions provided after converting them to |
| unicode. |
| """ |
| fields = ('nodes',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return ''.join(text_type(x.as_const(eval_ctx)) for x in self.nodes) |
| |
| |
| class Compare(Expr): |
| """Compares an expression with some other expressions. `ops` must be a |
| list of :class:`Operand`\s. |
| """ |
| fields = ('expr', 'ops') |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| result = value = self.expr.as_const(eval_ctx) |
| try: |
| for op in self.ops: |
| new_value = op.expr.as_const(eval_ctx) |
| result = _cmpop_to_func[op.op](value, new_value) |
| value = new_value |
| except Exception: |
| raise Impossible() |
| return result |
| |
| |
| class Operand(Helper): |
| """Holds an operator and an expression.""" |
| fields = ('op', 'expr') |
| |
| if __debug__: |
| Operand.__doc__ += '\nThe following operators are available: ' + \ |
| ', '.join(sorted('``%s``' % x for x in set(_binop_to_func) | |
| set(_uaop_to_func) | set(_cmpop_to_func))) |
| |
| |
| class Mul(BinExpr): |
| """Multiplies the left with the right node.""" |
| operator = '*' |
| |
| |
| class Div(BinExpr): |
| """Divides the left by the right node.""" |
| operator = '/' |
| |
| |
| class FloorDiv(BinExpr): |
| """Divides the left by the right node and truncates conver the |
| result into an integer by truncating. |
| """ |
| operator = '//' |
| |
| |
| class Add(BinExpr): |
| """Add the left to the right node.""" |
| operator = '+' |
| |
| |
| class Sub(BinExpr): |
| """Substract the right from the left node.""" |
| operator = '-' |
| |
| |
| class Mod(BinExpr): |
| """Left modulo right.""" |
| operator = '%' |
| |
| |
| class Pow(BinExpr): |
| """Left to the power of right.""" |
| operator = '**' |
| |
| |
| class And(BinExpr): |
| """Short circuited AND.""" |
| operator = 'and' |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return self.left.as_const(eval_ctx) and self.right.as_const(eval_ctx) |
| |
| |
| class Or(BinExpr): |
| """Short circuited OR.""" |
| operator = 'or' |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return self.left.as_const(eval_ctx) or self.right.as_const(eval_ctx) |
| |
| |
| class Not(UnaryExpr): |
| """Negate the expression.""" |
| operator = 'not' |
| |
| |
| class Neg(UnaryExpr): |
| """Make the expression negative.""" |
| operator = '-' |
| |
| |
| class Pos(UnaryExpr): |
| """Make the expression positive (noop for most expressions)""" |
| operator = '+' |
| |
| |
| # Helpers for extensions |
| |
| |
| class EnvironmentAttribute(Expr): |
| """Loads an attribute from the environment object. This is useful for |
| extensions that want to call a callback stored on the environment. |
| """ |
| fields = ('name',) |
| |
| |
| class ExtensionAttribute(Expr): |
| """Returns the attribute of an extension bound to the environment. |
| The identifier is the identifier of the :class:`Extension`. |
| |
| This node is usually constructed by calling the |
| :meth:`~jinja2.ext.Extension.attr` method on an extension. |
| """ |
| fields = ('identifier', 'name') |
| |
| |
| class ImportedName(Expr): |
| """If created with an import name the import name is returned on node |
| access. For example ``ImportedName('cgi.escape')`` returns the `escape` |
| function from the cgi module on evaluation. Imports are optimized by the |
| compiler so there is no need to assign them to local variables. |
| """ |
| fields = ('importname',) |
| |
| |
| class InternalName(Expr): |
| """An internal name in the compiler. You cannot create these nodes |
| yourself but the parser provides a |
| :meth:`~jinja2.parser.Parser.free_identifier` method that creates |
| a new identifier for you. This identifier is not available from the |
| template and is not threated specially by the compiler. |
| """ |
| fields = ('name',) |
| |
| def __init__(self): |
| raise TypeError('Can\'t create internal names. Use the ' |
| '`free_identifier` method on a parser.') |
| |
| |
| class MarkSafe(Expr): |
| """Mark the wrapped expression as safe (wrap it as `Markup`).""" |
| fields = ('expr',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| return Markup(self.expr.as_const(eval_ctx)) |
| |
| |
| class MarkSafeIfAutoescape(Expr): |
| """Mark the wrapped expression as safe (wrap it as `Markup`) but |
| only if autoescaping is active. |
| |
| .. versionadded:: 2.5 |
| """ |
| fields = ('expr',) |
| |
| def as_const(self, eval_ctx=None): |
| eval_ctx = get_eval_context(self, eval_ctx) |
| if eval_ctx.volatile: |
| raise Impossible() |
| expr = self.expr.as_const(eval_ctx) |
| if eval_ctx.autoescape: |
| return Markup(expr) |
| return expr |
| |
| |
| class ContextReference(Expr): |
| """Returns the current template context. It can be used like a |
| :class:`Name` node, with a ``'load'`` ctx and will return the |
| current :class:`~jinja2.runtime.Context` object. |
| |
| Here an example that assigns the current template name to a |
| variable named `foo`:: |
| |
| Assign(Name('foo', ctx='store'), |
| Getattr(ContextReference(), 'name')) |
| """ |
| |
| |
| class Continue(Stmt): |
| """Continue a loop.""" |
| |
| |
| class Break(Stmt): |
| """Break a loop.""" |
| |
| |
| class Scope(Stmt): |
| """An artificial scope.""" |
| fields = ('body',) |
| |
| |
| class EvalContextModifier(Stmt): |
| """Modifies the eval context. For each option that should be modified, |
| a :class:`Keyword` has to be added to the :attr:`options` list. |
| |
| Example to change the `autoescape` setting:: |
| |
| EvalContextModifier(options=[Keyword('autoescape', Const(True))]) |
| """ |
| fields = ('options',) |
| |
| |
| class ScopedEvalContextModifier(EvalContextModifier): |
| """Modifies the eval context and reverts it later. Works exactly like |
| :class:`EvalContextModifier` but will only modify the |
| :class:`~jinja2.nodes.EvalContext` for nodes in the :attr:`body`. |
| """ |
| fields = ('body',) |
| |
| |
| # make sure nobody creates custom nodes |
| def _failing_new(*args, **kwargs): |
| raise TypeError('can\'t create custom node types') |
| NodeType.__new__ = staticmethod(_failing_new); del _failing_new |
