Mini Shell
# -*- coding: utf-8 -*-
"""Compiles nodes from the parser into Python code."""
from collections import namedtuple
from functools import update_wrapper
from itertools import chain
from keyword import iskeyword as is_python_keyword
from markupsafe import escape
from markupsafe import Markup
from . import nodes
from ._compat import imap
from ._compat import iteritems
from ._compat import izip
from ._compat import NativeStringIO
from ._compat import range_type
from ._compat import string_types
from ._compat import text_type
from .exceptions import TemplateAssertionError
from .idtracking import Symbols
from .idtracking import VAR_LOAD_ALIAS
from .idtracking import VAR_LOAD_PARAMETER
from .idtracking import VAR_LOAD_RESOLVE
from .idtracking import VAR_LOAD_UNDEFINED
from .nodes import EvalContext
from .optimizer import Optimizer
from .utils import concat
from .visitor import NodeVisitor
operators = {
"eq": "==",
"ne": "!=",
"gt": ">",
"gteq": ">=",
"lt": "<",
"lteq": "<=",
"in": "in",
"notin": "not in",
}
# what method to iterate over items do we want to use for dict iteration
# in generated code? on 2.x let's go with iteritems, on 3.x with items
if hasattr(dict, "iteritems"):
dict_item_iter = "iteritems"
else:
dict_item_iter = "items"
code_features = ["division"]
# does this python version support generator stops? (PEP 0479)
try:
exec("from __future__ import generator_stop")
code_features.append("generator_stop")
except SyntaxError:
pass
# does this python version support yield from?
try:
exec("def f(): yield from x()")
except SyntaxError:
supports_yield_from = False
else:
supports_yield_from = True
def optimizeconst(f):
def new_func(self, node, frame, **kwargs):
# Only optimize if the frame is not volatile
if self.optimized and not frame.eval_ctx.volatile:
new_node = self.optimizer.visit(node, frame.eval_ctx)
if new_node != node:
return self.visit(new_node, frame)
return f(self, node, frame, **kwargs)
return update_wrapper(new_func, f)
def generate(
node, environment, name, filename, stream=None, defer_init=False, optimized=True
):
"""Generate the python source for a node tree."""
if not isinstance(node, nodes.Template):
raise TypeError("Can't compile non template nodes")
generator = environment.code_generator_class(
environment, name, filename, stream, defer_init, optimized
)
generator.visit(node)
if stream is None:
return generator.stream.getvalue()
def has_safe_repr(value):
"""Does the node have a safe representation?"""
if value is None or value is NotImplemented or value is Ellipsis:
return True
if type(value) in (bool, int, float, complex, range_type, Markup) + string_types:
return True
if type(value) in (tuple, list, set, frozenset):
for item in value:
if not has_safe_repr(item):
return False
return True
elif type(value) is dict:
for key, value in iteritems(value):
if not has_safe_repr(key):
return False
if not has_safe_repr(value):
return False
return True
return False
def find_undeclared(nodes, names):
"""Check if the names passed are accessed undeclared. The return value
is a set of all the undeclared names from the sequence of names found.
"""
visitor = UndeclaredNameVisitor(names)
try:
for node in nodes:
visitor.visit(node)
except VisitorExit:
pass
return visitor.undeclared
class MacroRef(object):
def __init__(self, node):
self.node = node
self.accesses_caller = False
self.accesses_kwargs = False
self.accesses_varargs = False
class Frame(object):
"""Holds compile time information for us."""
def __init__(self, eval_ctx, parent=None, level=None):
self.eval_ctx = eval_ctx
self.symbols = Symbols(parent and parent.symbols or None, level=level)
# a toplevel frame is the root + soft frames such as if conditions.
self.toplevel = False
# the root frame is basically just the outermost frame, so no if
# conditions. This information is used to optimize inheritance
# situations.
self.rootlevel = False
# in some dynamic inheritance situations the compiler needs to add
# write tests around output statements.
self.require_output_check = parent and parent.require_output_check
# inside some tags we are using a buffer rather than yield statements.
# this for example affects {% filter %} or {% macro %}. If a frame
# is buffered this variable points to the name of the list used as
# buffer.
self.buffer = None
# the name of the block we're in, otherwise None.
self.block = parent and parent.block or None
# the parent of this frame
self.parent = parent
if parent is not None:
self.buffer = parent.buffer
def copy(self):
"""Create a copy of the current one."""
rv = object.__new__(self.__class__)
rv.__dict__.update(self.__dict__)
rv.symbols = self.symbols.copy()
return rv
def inner(self, isolated=False):
"""Return an inner frame."""
if isolated:
return Frame(self.eval_ctx, level=self.symbols.level + 1)
return Frame(self.eval_ctx, self)
def soft(self):
"""Return a soft frame. A soft frame may not be modified as
standalone thing as it shares the resources with the frame it
was created of, but it's not a rootlevel frame any longer.
This is only used to implement if-statements.
"""
rv = self.copy()
rv.rootlevel = False
return rv
__copy__ = copy
class VisitorExit(RuntimeError):
"""Exception used by the `UndeclaredNameVisitor` to signal a stop."""
class DependencyFinderVisitor(NodeVisitor):
"""A visitor that collects filter and test calls."""
def __init__(self):
self.filters = set()
self.tests = set()
def visit_Filter(self, node):
self.generic_visit(node)
self.filters.add(node.name)
def visit_Test(self, node):
self.generic_visit(node)
self.tests.add(node.name)
def visit_Block(self, node):
"""Stop visiting at blocks."""
class UndeclaredNameVisitor(NodeVisitor):
"""A visitor that checks if a name is accessed without being
declared. This is different from the frame visitor as it will
not stop at closure frames.
"""
def __init__(self, names):
self.names = set(names)
self.undeclared = set()
def visit_Name(self, node):
if node.ctx == "load" and node.name in self.names:
self.undeclared.add(node.name)
if self.undeclared == self.names:
raise VisitorExit()
else:
self.names.discard(node.name)
def visit_Block(self, node):
"""Stop visiting a blocks."""
class CompilerExit(Exception):
"""Raised if the compiler encountered a situation where it just
doesn't make sense to further process the code. Any block that
raises such an exception is not further processed.
"""
class CodeGenerator(NodeVisitor):
def __init__(
self, environment, name, filename, stream=None, defer_init=False, optimized=True
):
if stream is None:
stream = NativeStringIO()
self.environment = environment
self.name = name
self.filename = filename
self.stream = stream
self.created_block_context = False
self.defer_init = defer_init
self.optimized = optimized
if optimized:
self.optimizer = Optimizer(environment)
# aliases for imports
self.import_aliases = {}
# a registry for all blocks. Because blocks are moved out
# into the global python scope they are registered here
self.blocks = {}
# the number of extends statements so far
self.extends_so_far = 0
# some templates have a rootlevel extends. In this case we
# can safely assume that we're a child template and do some
# more optimizations.
self.has_known_extends = False
# the current line number
self.code_lineno = 1
# registry of all filters and tests (global, not block local)
self.tests = {}
self.filters = {}
# the debug information
self.debug_info = []
self._write_debug_info = None
# the number of new lines before the next write()
self._new_lines = 0
# the line number of the last written statement
self._last_line = 0
# true if nothing was written so far.
self._first_write = True
# used by the `temporary_identifier` method to get new
# unique, temporary identifier
self._last_identifier = 0
# the current indentation
self._indentation = 0
# Tracks toplevel assignments
self._assign_stack = []
# Tracks parameter definition blocks
self._param_def_block = []
# Tracks the current context.
self._context_reference_stack = ["context"]
# -- Various compilation helpers
def fail(self, msg, lineno):
"""Fail with a :exc:`TemplateAssertionError`."""
raise TemplateAssertionError(msg, lineno, self.name, self.filename)
def temporary_identifier(self):
"""Get a new unique identifier."""
self._last_identifier += 1
return "t_%d" % self._last_identifier
def buffer(self, frame):
"""Enable buffering for the frame from that point onwards."""
frame.buffer = self.temporary_identifier()
self.writeline("%s = []" % frame.buffer)
def return_buffer_contents(self, frame, force_unescaped=False):
"""Return the buffer contents of the frame."""
if not force_unescaped:
if frame.eval_ctx.volatile:
self.writeline("if context.eval_ctx.autoescape:")
self.indent()
self.writeline("return Markup(concat(%s))" % frame.buffer)
self.outdent()
self.writeline("else:")
self.indent()
self.writeline("return concat(%s)" % frame.buffer)
self.outdent()
return
elif frame.eval_ctx.autoescape:
self.writeline("return Markup(concat(%s))" % frame.buffer)
return
self.writeline("return concat(%s)" % frame.buffer)
def indent(self):
"""Indent by one."""
self._indentation += 1
def outdent(self, step=1):
"""Outdent by step."""
self._indentation -= step
def start_write(self, frame, node=None):
"""Yield or write into the frame buffer."""
if frame.buffer is None:
self.writeline("yield ", node)
else:
self.writeline("%s.append(" % frame.buffer, node)
def end_write(self, frame):
"""End the writing process started by `start_write`."""
if frame.buffer is not None:
self.write(")")
def simple_write(self, s, frame, node=None):
"""Simple shortcut for start_write + write + end_write."""
self.start_write(frame, node)
self.write(s)
self.end_write(frame)
def blockvisit(self, nodes, frame):
"""Visit a list of nodes as block in a frame. If the current frame
is no buffer a dummy ``if 0: yield None`` is written automatically.
"""
try:
self.writeline("pass")
for node in nodes:
self.visit(node, frame)
except CompilerExit:
pass
def write(self, x):
"""Write a string into the output stream."""
if self._new_lines:
if not self._first_write:
self.stream.write("\n" * self._new_lines)
self.code_lineno += self._new_lines
if self._write_debug_info is not None:
self.debug_info.append((self._write_debug_info, self.code_lineno))
self._write_debug_info = None
self._first_write = False
self.stream.write(" " * self._indentation)
self._new_lines = 0
self.stream.write(x)
def writeline(self, x, node=None, extra=0):
"""Combination of newline and write."""
self.newline(node, extra)
self.write(x)
def newline(self, node=None, extra=0):
"""Add one or more newlines before the next write."""
self._new_lines = max(self._new_lines, 1 + extra)
if node is not None and node.lineno != self._last_line:
self._write_debug_info = node.lineno
self._last_line = node.lineno
def signature(self, node, frame, extra_kwargs=None):
"""Writes a function call to the stream for the current node.
A leading comma is added automatically. The extra keyword
arguments may not include python keywords otherwise a syntax
error could occur. The extra keyword arguments should be given
as python dict.
"""
# if any of the given keyword arguments is a python keyword
# we have to make sure that no invalid call is created.
kwarg_workaround = False
for kwarg in chain((x.key for x in node.kwargs), extra_kwargs or ()):
if is_python_keyword(kwarg):
kwarg_workaround = True
break
for arg in node.args:
self.write(", ")
self.visit(arg, frame)
if not kwarg_workaround:
for kwarg in node.kwargs:
self.write(", ")
self.visit(kwarg, frame)
if extra_kwargs is not None:
for key, value in iteritems(extra_kwargs):
self.write(", %s=%s" % (key, value))
if node.dyn_args:
self.write(", *")
self.visit(node.dyn_args, frame)
if kwarg_workaround:
if node.dyn_kwargs is not None:
self.write(", **dict({")
else:
self.write(", **{")
for kwarg in node.kwargs:
self.write("%r: " % kwarg.key)
self.visit(kwarg.value, frame)
self.write(", ")
if extra_kwargs is not None:
for key, value in iteritems(extra_kwargs):
self.write("%r: %s, " % (key, value))
if node.dyn_kwargs is not None:
self.write("}, **")
self.visit(node.dyn_kwargs, frame)
self.write(")")
else:
self.write("}")
elif node.dyn_kwargs is not None:
self.write(", **")
self.visit(node.dyn_kwargs, frame)
def pull_dependencies(self, nodes):
"""Pull all the dependencies."""
visitor = DependencyFinderVisitor()
for node in nodes:
visitor.visit(node)
for dependency in "filters", "tests":
mapping = getattr(self, dependency)
for name in getattr(visitor, dependency):
if name not in mapping:
mapping[name] = self.temporary_identifier()
self.writeline(
"%s = environment.%s[%r]" % (mapping[name], dependency, name)
)
def enter_frame(self, frame):
undefs = []
for target, (action, param) in iteritems(frame.symbols.loads):
if action == VAR_LOAD_PARAMETER:
pass
elif action == VAR_LOAD_RESOLVE:
self.writeline("%s = %s(%r)" % (target, self.get_resolve_func(), param))
elif action == VAR_LOAD_ALIAS:
self.writeline("%s = %s" % (target, param))
elif action == VAR_LOAD_UNDEFINED:
undefs.append(target)
else:
raise NotImplementedError("unknown load instruction")
if undefs:
self.writeline("%s = missing" % " = ".join(undefs))
def leave_frame(self, frame, with_python_scope=False):
if not with_python_scope:
undefs = []
for target, _ in iteritems(frame.symbols.loads):
undefs.append(target)
if undefs:
self.writeline("%s = missing" % " = ".join(undefs))
def func(self, name):
if self.environment.is_async:
return "async def %s" % name
return "def %s" % name
def macro_body(self, node, frame):
"""Dump the function def of a macro or call block."""
frame = frame.inner()
frame.symbols.analyze_node(node)
macro_ref = MacroRef(node)
explicit_caller = None
skip_special_params = set()
args = []
for idx, arg in enumerate(node.args):
if arg.name == "caller":
explicit_caller = idx
if arg.name in ("kwargs", "varargs"):
skip_special_params.add(arg.name)
args.append(frame.symbols.ref(arg.name))
undeclared = find_undeclared(node.body, ("caller", "kwargs", "varargs"))
if "caller" in undeclared:
# In older Jinja versions there was a bug that allowed caller
# to retain the special behavior even if it was mentioned in
# the argument list. However thankfully this was only really
# working if it was the last argument. So we are explicitly
# checking this now and error out if it is anywhere else in
# the argument list.
if explicit_caller is not None:
try:
node.defaults[explicit_caller - len(node.args)]
except IndexError:
self.fail(
"When defining macros or call blocks the "
'special "caller" argument must be omitted '
"or be given a default.",
node.lineno,
)
else:
args.append(frame.symbols.declare_parameter("caller"))
macro_ref.accesses_caller = True
if "kwargs" in undeclared and "kwargs" not in skip_special_params:
args.append(frame.symbols.declare_parameter("kwargs"))
macro_ref.accesses_kwargs = True
if "varargs" in undeclared and "varargs" not in skip_special_params:
args.append(frame.symbols.declare_parameter("varargs"))
macro_ref.accesses_varargs = True
# macros are delayed, they never require output checks
frame.require_output_check = False
frame.symbols.analyze_node(node)
self.writeline("%s(%s):" % (self.func("macro"), ", ".join(args)), node)
self.indent()
self.buffer(frame)
self.enter_frame(frame)
self.push_parameter_definitions(frame)
for idx, arg in enumerate(node.args):
ref = frame.symbols.ref(arg.name)
self.writeline("if %s is missing:" % ref)
self.indent()
try:
default = node.defaults[idx - len(node.args)]
except IndexError:
self.writeline(
"%s = undefined(%r, name=%r)"
% (ref, "parameter %r was not provided" % arg.name, arg.name)
)
else:
self.writeline("%s = " % ref)
self.visit(default, frame)
self.mark_parameter_stored(ref)
self.outdent()
self.pop_parameter_definitions()
self.blockvisit(node.body, frame)
self.return_buffer_contents(frame, force_unescaped=True)
self.leave_frame(frame, with_python_scope=True)
self.outdent()
return frame, macro_ref
def macro_def(self, macro_ref, frame):
"""Dump the macro definition for the def created by macro_body."""
arg_tuple = ", ".join(repr(x.name) for x in macro_ref.node.args)
name = getattr(macro_ref.node, "name", None)
if len(macro_ref.node.args) == 1:
arg_tuple += ","
self.write(
"Macro(environment, macro, %r, (%s), %r, %r, %r, "
"context.eval_ctx.autoescape)"
% (
name,
arg_tuple,
macro_ref.accesses_kwargs,
macro_ref.accesses_varargs,
macro_ref.accesses_caller,
)
)
def position(self, node):
"""Return a human readable position for the node."""
rv = "line %d" % node.lineno
if self.name is not None:
rv += " in " + repr(self.name)
return rv
def dump_local_context(self, frame):
return "{%s}" % ", ".join(
"%r: %s" % (name, target)
for name, target in iteritems(frame.symbols.dump_stores())
)
def write_commons(self):
"""Writes a common preamble that is used by root and block functions.
Primarily this sets up common local helpers and enforces a generator
through a dead branch.
"""
self.writeline("resolve = context.resolve_or_missing")
self.writeline("undefined = environment.undefined")
# always use the standard Undefined class for the implicit else of
# conditional expressions
self.writeline("cond_expr_undefined = Undefined")
self.writeline("if 0: yield None")
def push_parameter_definitions(self, frame):
"""Pushes all parameter targets from the given frame into a local
stack that permits tracking of yet to be assigned parameters. In
particular this enables the optimization from `visit_Name` to skip
undefined expressions for parameters in macros as macros can reference
otherwise unbound parameters.
"""
self._param_def_block.append(frame.symbols.dump_param_targets())
def pop_parameter_definitions(self):
"""Pops the current parameter definitions set."""
self._param_def_block.pop()
def mark_parameter_stored(self, target):
"""Marks a parameter in the current parameter definitions as stored.
This will skip the enforced undefined checks.
"""
if self._param_def_block:
self._param_def_block[-1].discard(target)
def push_context_reference(self, target):
self._context_reference_stack.append(target)
def pop_context_reference(self):
self._context_reference_stack.pop()
def get_context_ref(self):
return self._context_reference_stack[-1]
def get_resolve_func(self):
target = self._context_reference_stack[-1]
if target == "context":
return "resolve"
return "%s.resolve" % target
def derive_context(self, frame):
return "%s.derived(%s)" % (
self.get_context_ref(),
self.dump_local_context(frame),
)
def parameter_is_undeclared(self, target):
"""Checks if a given target is an undeclared parameter."""
if not self._param_def_block:
return False
return target in self._param_def_block[-1]
def push_assign_tracking(self):
"""Pushes a new layer for assignment tracking."""
self._assign_stack.append(set())
def pop_assign_tracking(self, frame):
"""Pops the topmost level for assignment tracking and updates the
context variables if necessary.
"""
vars = self._assign_stack.pop()
if not frame.toplevel or not vars:
return
public_names = [x for x in vars if x[:1] != "_"]
if len(vars) == 1:
name = next(iter(vars))
ref = frame.symbols.ref(name)
self.writeline("context.vars[%r] = %s" % (name, ref))
else:
self.writeline("context.vars.update({")
for idx, name in enumerate(vars):
if idx:
self.write(", ")
ref = frame.symbols.ref(name)
self.write("%r: %s" % (name, ref))
self.write("})")
if public_names:
if len(public_names) == 1:
self.writeline("context.exported_vars.add(%r)" % public_names[0])
else:
self.writeline(
"context.exported_vars.update((%s))"
% ", ".join(imap(repr, public_names))
)
# -- Statement Visitors
def visit_Template(self, node, frame=None):
assert frame is None, "no root frame allowed"
eval_ctx = EvalContext(self.environment, self.name)
from .runtime import exported
self.writeline("from __future__ import %s" % ", ".join(code_features))
self.writeline("from jinja2.runtime import " + ", ".join(exported))
if self.environment.is_async:
self.writeline(
"from jinja2.asyncsupport import auto_await, "
"auto_aiter, AsyncLoopContext"
)
# if we want a deferred initialization we cannot move the
# environment into a local name
envenv = not self.defer_init and ", environment=environment" or ""
# do we have an extends tag at all? If not, we can save some
# overhead by just not processing any inheritance code.
have_extends = node.find(nodes.Extends) is not None
# find all blocks
for block in node.find_all(nodes.Block):
if block.name in self.blocks:
self.fail("block %r defined twice" % block.name, block.lineno)
self.blocks[block.name] = block
# find all imports and import them
for import_ in node.find_all(nodes.ImportedName):
if import_.importname not in self.import_aliases:
imp = import_.importname
self.import_aliases[imp] = alias = self.temporary_identifier()
if "." in imp:
module, obj = imp.rsplit(".", 1)
self.writeline("from %s import %s as %s" % (module, obj, alias))
else:
self.writeline("import %s as %s" % (imp, alias))
# add the load name
self.writeline("name = %r" % self.name)
# generate the root render function.
self.writeline(
"%s(context, missing=missing%s):" % (self.func("root"), envenv), extra=1
)
self.indent()
self.write_commons()
# process the root
frame = Frame(eval_ctx)
if "self" in find_undeclared(node.body, ("self",)):
ref = frame.symbols.declare_parameter("self")
self.writeline("%s = TemplateReference(context)" % ref)
frame.symbols.analyze_node(node)
frame.toplevel = frame.rootlevel = True
frame.require_output_check = have_extends and not self.has_known_extends
if have_extends:
self.writeline("parent_template = None")
self.enter_frame(frame)
self.pull_dependencies(node.body)
self.blockvisit(node.body, frame)
self.leave_frame(frame, with_python_scope=True)
self.outdent()
# make sure that the parent root is called.
if have_extends:
if not self.has_known_extends:
self.indent()
self.writeline("if parent_template is not None:")
self.indent()
if supports_yield_from and not self.environment.is_async:
self.writeline("yield from parent_template.root_render_func(context)")
else:
self.writeline(
"%sfor event in parent_template."
"root_render_func(context):"
% (self.environment.is_async and "async " or "")
)
self.indent()
self.writeline("yield event")
self.outdent()
self.outdent(1 + (not self.has_known_extends))
# at this point we now have the blocks collected and can visit them too.
for name, block in iteritems(self.blocks):
self.writeline(
"%s(context, missing=missing%s):"
% (self.func("block_" + name), envenv),
block,
1,
)
self.indent()
self.write_commons()
# It's important that we do not make this frame a child of the
# toplevel template. This would cause a variety of
# interesting issues with identifier tracking.
block_frame = Frame(eval_ctx)
undeclared = find_undeclared(block.body, ("self", "super"))
if "self" in undeclared:
ref = block_frame.symbols.declare_parameter("self")
self.writeline("%s = TemplateReference(context)" % ref)
if "super" in undeclared:
ref = block_frame.symbols.declare_parameter("super")
self.writeline("%s = context.super(%r, block_%s)" % (ref, name, name))
block_frame.symbols.analyze_node(block)
block_frame.block = name
self.enter_frame(block_frame)
self.pull_dependencies(block.body)
self.blockvisit(block.body, block_frame)
self.leave_frame(block_frame, with_python_scope=True)
self.outdent()
self.writeline(
"blocks = {%s}" % ", ".join("%r: block_%s" % (x, x) for x in self.blocks),
extra=1,
)
# add a function that returns the debug info
self.writeline(
"debug_info = %r" % "&".join("%s=%s" % x for x in self.debug_info)
)
def visit_Block(self, node, frame):
"""Call a block and register it for the template."""
level = 0
if frame.toplevel:
# if we know that we are a child template, there is no need to
# check if we are one
if self.has_known_extends:
return
if self.extends_so_far > 0:
self.writeline("if parent_template is None:")
self.indent()
level += 1
if node.scoped:
context = self.derive_context(frame)
else:
context = self.get_context_ref()
if (
supports_yield_from
and not self.environment.is_async
and frame.buffer is None
):
self.writeline(
"yield from context.blocks[%r][0](%s)" % (node.name, context), node
)
else:
loop = self.environment.is_async and "async for" or "for"
self.writeline(
"%s event in context.blocks[%r][0](%s):" % (loop, node.name, context),
node,
)
self.indent()
self.simple_write("event", frame)
self.outdent()
self.outdent(level)
def visit_Extends(self, node, frame):
"""Calls the extender."""
if not frame.toplevel:
self.fail("cannot use extend from a non top-level scope", node.lineno)
# if the number of extends statements in general is zero so
# far, we don't have to add a check if something extended
# the template before this one.
if self.extends_so_far > 0:
# if we have a known extends we just add a template runtime
# error into the generated code. We could catch that at compile
# time too, but i welcome it not to confuse users by throwing the
# same error at different times just "because we can".
if not self.has_known_extends:
self.writeline("if parent_template is not None:")
self.indent()
self.writeline("raise TemplateRuntimeError(%r)" % "extended multiple times")
# if we have a known extends already we don't need that code here
# as we know that the template execution will end here.
if self.has_known_extends:
raise CompilerExit()
else:
self.outdent()
self.writeline("parent_template = environment.get_template(", node)
self.visit(node.template, frame)
self.write(", %r)" % self.name)
self.writeline(
"for name, parent_block in parent_template.blocks.%s():" % dict_item_iter
)
self.indent()
self.writeline("context.blocks.setdefault(name, []).append(parent_block)")
self.outdent()
# if this extends statement was in the root level we can take
# advantage of that information and simplify the generated code
# in the top level from this point onwards
if frame.rootlevel:
self.has_known_extends = True
# and now we have one more
self.extends_so_far += 1
def visit_Include(self, node, frame):
"""Handles includes."""
if node.ignore_missing:
self.writeline("try:")
self.indent()
func_name = "get_or_select_template"
if isinstance(node.template, nodes.Const):
if isinstance(node.template.value, string_types):
func_name = "get_template"
elif isinstance(node.template.value, (tuple, list)):
func_name = "select_template"
elif isinstance(node.template, (nodes.Tuple, nodes.List)):
func_name = "select_template"
self.writeline("template = environment.%s(" % func_name, node)
self.visit(node.template, frame)
self.write(", %r)" % self.name)
if node.ignore_missing:
self.outdent()
self.writeline("except TemplateNotFound:")
self.indent()
self.writeline("pass")
self.outdent()
self.writeline("else:")
self.indent()
skip_event_yield = False
if node.with_context:
loop = self.environment.is_async and "async for" or "for"
self.writeline(
"%s event in template.root_render_func("
"template.new_context(context.get_all(), True, "
"%s)):" % (loop, self.dump_local_context(frame))
)
elif self.environment.is_async:
self.writeline(
"for event in (await "
"template._get_default_module_async())"
"._body_stream:"
)
else:
if supports_yield_from:
self.writeline("yield from template._get_default_module()._body_stream")
skip_event_yield = True
else:
self.writeline(
"for event in template._get_default_module()._body_stream:"
)
if not skip_event_yield:
self.indent()
self.simple_write("event", frame)
self.outdent()
if node.ignore_missing:
self.outdent()
def visit_Import(self, node, frame):
"""Visit regular imports."""
self.writeline("%s = " % frame.symbols.ref(node.target), node)
if frame.toplevel:
self.write("context.vars[%r] = " % node.target)
if self.environment.is_async:
self.write("await ")
self.write("environment.get_template(")
self.visit(node.template, frame)
self.write(", %r)." % self.name)
if node.with_context:
self.write(
"make_module%s(context.get_all(), True, %s)"
% (
self.environment.is_async and "_async" or "",
self.dump_local_context(frame),
)
)
elif self.environment.is_async:
self.write("_get_default_module_async()")
else:
self.write("_get_default_module()")
if frame.toplevel and not node.target.startswith("_"):
self.writeline("context.exported_vars.discard(%r)" % node.target)
def visit_FromImport(self, node, frame):
"""Visit named imports."""
self.newline(node)
self.write(
"included_template = %senvironment.get_template("
% (self.environment.is_async and "await " or "")
)
self.visit(node.template, frame)
self.write(", %r)." % self.name)
if node.with_context:
self.write(
"make_module%s(context.get_all(), True, %s)"
% (
self.environment.is_async and "_async" or "",
self.dump_local_context(frame),
)
)
elif self.environment.is_async:
self.write("_get_default_module_async()")
else:
self.write("_get_default_module()")
var_names = []
discarded_names = []
for name in node.names:
if isinstance(name, tuple):
name, alias = name
else:
alias = name
self.writeline(
"%s = getattr(included_template, "
"%r, missing)" % (frame.symbols.ref(alias), name)
)
self.writeline("if %s is missing:" % frame.symbols.ref(alias))
self.indent()
self.writeline(
"%s = undefined(%r %% "
"included_template.__name__, "
"name=%r)"
% (
frame.symbols.ref(alias),
"the template %%r (imported on %s) does "
"not export the requested name %s"
% (self.position(node), repr(name)),
name,
)
)
self.outdent()
if frame.toplevel:
var_names.append(alias)
if not alias.startswith("_"):
discarded_names.append(alias)
if var_names:
if len(var_names) == 1:
name = var_names[0]
self.writeline(
"context.vars[%r] = %s" % (name, frame.symbols.ref(name))
)
else:
self.writeline(
"context.vars.update({%s})"
% ", ".join(
"%r: %s" % (name, frame.symbols.ref(name)) for name in var_names
)
)
if discarded_names:
if len(discarded_names) == 1:
self.writeline("context.exported_vars.discard(%r)" % discarded_names[0])
else:
self.writeline(
"context.exported_vars.difference_"
"update((%s))" % ", ".join(imap(repr, discarded_names))
)
def visit_For(self, node, frame):
loop_frame = frame.inner()
test_frame = frame.inner()
else_frame = frame.inner()
# try to figure out if we have an extended loop. An extended loop
# is necessary if the loop is in recursive mode if the special loop
# variable is accessed in the body.
extended_loop = node.recursive or "loop" in find_undeclared(
node.iter_child_nodes(only=("body",)), ("loop",)
)
loop_ref = None
if extended_loop:
loop_ref = loop_frame.symbols.declare_parameter("loop")
loop_frame.symbols.analyze_node(node, for_branch="body")
if node.else_:
else_frame.symbols.analyze_node(node, for_branch="else")
if node.test:
loop_filter_func = self.temporary_identifier()
test_frame.symbols.analyze_node(node, for_branch="test")
self.writeline("%s(fiter):" % self.func(loop_filter_func), node.test)
self.indent()
self.enter_frame(test_frame)
self.writeline(self.environment.is_async and "async for " or "for ")
self.visit(node.target, loop_frame)
self.write(" in ")
self.write(self.environment.is_async and "auto_aiter(fiter)" or "fiter")
self.write(":")
self.indent()
self.writeline("if ", node.test)
self.visit(node.test, test_frame)
self.write(":")
self.indent()
self.writeline("yield ")
self.visit(node.target, loop_frame)
self.outdent(3)
self.leave_frame(test_frame, with_python_scope=True)
# if we don't have an recursive loop we have to find the shadowed
# variables at that point. Because loops can be nested but the loop
# variable is a special one we have to enforce aliasing for it.
if node.recursive:
self.writeline(
"%s(reciter, loop_render_func, depth=0):" % self.func("loop"), node
)
self.indent()
self.buffer(loop_frame)
# Use the same buffer for the else frame
else_frame.buffer = loop_frame.buffer
# make sure the loop variable is a special one and raise a template
# assertion error if a loop tries to write to loop
if extended_loop:
self.writeline("%s = missing" % loop_ref)
for name in node.find_all(nodes.Name):
if name.ctx == "store" and name.name == "loop":
self.fail(
"Can't assign to special loop variable in for-loop target",
name.lineno,
)
if node.else_:
iteration_indicator = self.temporary_identifier()
self.writeline("%s = 1" % iteration_indicator)
self.writeline(self.environment.is_async and "async for " or "for ", node)
self.visit(node.target, loop_frame)
if extended_loop:
if self.environment.is_async:
self.write(", %s in AsyncLoopContext(" % loop_ref)
else:
self.write(", %s in LoopContext(" % loop_ref)
else:
self.write(" in ")
if node.test:
self.write("%s(" % loop_filter_func)
if node.recursive:
self.write("reciter")
else:
if self.environment.is_async and not extended_loop:
self.write("auto_aiter(")
self.visit(node.iter, frame)
if self.environment.is_async and not extended_loop:
self.write(")")
if node.test:
self.write(")")
if node.recursive:
self.write(", undefined, loop_render_func, depth):")
else:
self.write(extended_loop and ", undefined):" or ":")
self.indent()
self.enter_frame(loop_frame)
self.blockvisit(node.body, loop_frame)
if node.else_:
self.writeline("%s = 0" % iteration_indicator)
self.outdent()
self.leave_frame(
loop_frame, with_python_scope=node.recursive and not node.else_
)
if node.else_:
self.writeline("if %s:" % iteration_indicator)
self.indent()
self.enter_frame(else_frame)
self.blockvisit(node.else_, else_frame)
self.leave_frame(else_frame)
self.outdent()
# if the node was recursive we have to return the buffer contents
# and start the iteration code
if node.recursive:
self.return_buffer_contents(loop_frame)
self.outdent()
self.start_write(frame, node)
if self.environment.is_async:
self.write("await ")
self.write("loop(")
if self.environment.is_async:
self.write("auto_aiter(")
self.visit(node.iter, frame)
if self.environment.is_async:
self.write(")")
self.write(", loop)")
self.end_write(frame)
def visit_If(self, node, frame):
if_frame = frame.soft()
self.writeline("if ", node)
self.visit(node.test, if_frame)
self.write(":")
self.indent()
self.blockvisit(node.body, if_frame)
self.outdent()
for elif_ in node.elif_:
self.writeline("elif ", elif_)
self.visit(elif_.test, if_frame)
self.write(":")
self.indent()
self.blockvisit(elif_.body, if_frame)
self.outdent()
if node.else_:
self.writeline("else:")
self.indent()
self.blockvisit(node.else_, if_frame)
self.outdent()
def visit_Macro(self, node, frame):
macro_frame, macro_ref = self.macro_body(node, frame)
self.newline()
if frame.toplevel:
if not node.name.startswith("_"):
self.write("context.exported_vars.add(%r)" % node.name)
self.writeline("context.vars[%r] = " % node.name)
self.write("%s = " % frame.symbols.ref(node.name))
self.macro_def(macro_ref, macro_frame)
def visit_CallBlock(self, node, frame):
call_frame, macro_ref = self.macro_body(node, frame)
self.writeline("caller = ")
self.macro_def(macro_ref, call_frame)
self.start_write(frame, node)
self.visit_Call(node.call, frame, forward_caller=True)
self.end_write(frame)
def visit_FilterBlock(self, node, frame):
filter_frame = frame.inner()
filter_frame.symbols.analyze_node(node)
self.enter_frame(filter_frame)
self.buffer(filter_frame)
self.blockvisit(node.body, filter_frame)
self.start_write(frame, node)
self.visit_Filter(node.filter, filter_frame)
self.end_write(frame)
self.leave_frame(filter_frame)
def visit_With(self, node, frame):
with_frame = frame.inner()
with_frame.symbols.analyze_node(node)
self.enter_frame(with_frame)
for target, expr in izip(node.targets, node.values):
self.newline()
self.visit(target, with_frame)
self.write(" = ")
self.visit(expr, frame)
self.blockvisit(node.body, with_frame)
self.leave_frame(with_frame)
def visit_ExprStmt(self, node, frame):
self.newline(node)
self.visit(node.node, frame)
_FinalizeInfo = namedtuple("_FinalizeInfo", ("const", "src"))
#: The default finalize function if the environment isn't configured
#: with one. Or if the environment has one, this is called on that
#: function's output for constants.
_default_finalize = text_type
_finalize = None
def _make_finalize(self):
"""Build the finalize function to be used on constants and at
runtime. Cached so it's only created once for all output nodes.
Returns a ``namedtuple`` with the following attributes:
``const``
A function to finalize constant data at compile time.
``src``
Source code to output around nodes to be evaluated at
runtime.
"""
if self._finalize is not None:
return self._finalize
finalize = default = self._default_finalize
src = None
if self.environment.finalize:
src = "environment.finalize("
env_finalize = self.environment.finalize
def finalize(value):
return default(env_finalize(value))
if getattr(env_finalize, "contextfunction", False) is True:
src += "context, "
finalize = None # noqa: F811
elif getattr(env_finalize, "evalcontextfunction", False) is True:
src += "context.eval_ctx, "
finalize = None
elif getattr(env_finalize, "environmentfunction", False) is True:
src += "environment, "
def finalize(value):
return default(env_finalize(self.environment, value))
self._finalize = self._FinalizeInfo(finalize, src)
return self._finalize
def _output_const_repr(self, group):
"""Given a group of constant values converted from ``Output``
child nodes, produce a string to write to the template module
source.
"""
return repr(concat(group))
def _output_child_to_const(self, node, frame, finalize):
"""Try to optimize a child of an ``Output`` node by trying to
convert it to constant, finalized data at compile time.
If :exc:`Impossible` is raised, the node is not constant and
will be evaluated at runtime. Any other exception will also be
evaluated at runtime for easier debugging.
"""
const = node.as_const(frame.eval_ctx)
if frame.eval_ctx.autoescape:
const = escape(const)
# Template data doesn't go through finalize.
if isinstance(node, nodes.TemplateData):
return text_type(const)
return finalize.const(const)
def _output_child_pre(self, node, frame, finalize):
"""Output extra source code before visiting a child of an
``Output`` node.
"""
if frame.eval_ctx.volatile:
self.write("(escape if context.eval_ctx.autoescape else to_string)(")
elif frame.eval_ctx.autoescape:
self.write("escape(")
else:
self.write("to_string(")
if finalize.src is not None:
self.write(finalize.src)
def _output_child_post(self, node, frame, finalize):
"""Output extra source code after visiting a child of an
``Output`` node.
"""
self.write(")")
if finalize.src is not None:
self.write(")")
def visit_Output(self, node, frame):
# If an extends is active, don't render outside a block.
if frame.require_output_check:
# A top-level extends is known to exist at compile time.
if self.has_known_extends:
return
self.writeline("if parent_template is None:")
self.indent()
finalize = self._make_finalize()
body = []
# Evaluate constants at compile time if possible. Each item in
# body will be either a list of static data or a node to be
# evaluated at runtime.
for child in node.nodes:
try:
if not (
# If the finalize function requires runtime context,
# constants can't be evaluated at compile time.
finalize.const
# Unless it's basic template data that won't be
# finalized anyway.
or isinstance(child, nodes.TemplateData)
):
raise nodes.Impossible()
const = self._output_child_to_const(child, frame, finalize)
except (nodes.Impossible, Exception):
# The node was not constant and needs to be evaluated at
# runtime. Or another error was raised, which is easier
# to debug at runtime.
body.append(child)
continue
if body and isinstance(body[-1], list):
body[-1].append(const)
else:
body.append([const])
if frame.buffer is not None:
if len(body) == 1:
self.writeline("%s.append(" % frame.buffer)
else:
self.writeline("%s.extend((" % frame.buffer)
self.indent()
for item in body:
if isinstance(item, list):
# A group of constant data to join and output.
val = self._output_const_repr(item)
if frame.buffer is None:
self.writeline("yield " + val)
else:
self.writeline(val + ",")
else:
if frame.buffer is None:
self.writeline("yield ", item)
else:
self.newline(item)
# A node to be evaluated at runtime.
self._output_child_pre(item, frame, finalize)
self.visit(item, frame)
self._output_child_post(item, frame, finalize)
if frame.buffer is not None:
self.write(",")
if frame.buffer is not None:
self.outdent()
self.writeline(")" if len(body) == 1 else "))")
if frame.require_output_check:
self.outdent()
def visit_Assign(self, node, frame):
self.push_assign_tracking()
self.newline(node)
self.visit(node.target, frame)
self.write(" = ")
self.visit(node.node, frame)
self.pop_assign_tracking(frame)
def visit_AssignBlock(self, node, frame):
self.push_assign_tracking()
block_frame = frame.inner()
# This is a special case. Since a set block always captures we
# will disable output checks. This way one can use set blocks
# toplevel even in extended templates.
block_frame.require_output_check = False
block_frame.symbols.analyze_node(node)
self.enter_frame(block_frame)
self.buffer(block_frame)
self.blockvisit(node.body, block_frame)
self.newline(node)
self.visit(node.target, frame)
self.write(" = (Markup if context.eval_ctx.autoescape else identity)(")
if node.filter is not None:
self.visit_Filter(node.filter, block_frame)
else:
self.write("concat(%s)" % block_frame.buffer)
self.write(")")
self.pop_assign_tracking(frame)
self.leave_frame(block_frame)
# -- Expression Visitors
def visit_Name(self, node, frame):
if node.ctx == "store" and frame.toplevel:
if self._assign_stack:
self._assign_stack[-1].add(node.name)
ref = frame.symbols.ref(node.name)
# If we are looking up a variable we might have to deal with the
# case where it's undefined. We can skip that case if the load
# instruction indicates a parameter which are always defined.
if node.ctx == "load":
load = frame.symbols.find_load(ref)
if not (
load is not None
and load[0] == VAR_LOAD_PARAMETER
and not self.parameter_is_undeclared(ref)
):
self.write(
"(undefined(name=%r) if %s is missing else %s)"
% (node.name, ref, ref)
)
return
self.write(ref)
def visit_NSRef(self, node, frame):
# NSRefs can only be used to store values; since they use the normal
# `foo.bar` notation they will be parsed as a normal attribute access
# when used anywhere but in a `set` context
ref = frame.symbols.ref(node.name)
self.writeline("if not isinstance(%s, Namespace):" % ref)
self.indent()
self.writeline(
"raise TemplateRuntimeError(%r)"
% "cannot assign attribute on non-namespace object"
)
self.outdent()
self.writeline("%s[%r]" % (ref, node.attr))
def visit_Const(self, node, frame):
val = node.as_const(frame.eval_ctx)
if isinstance(val, float):
self.write(str(val))
else:
self.write(repr(val))
def visit_TemplateData(self, node, frame):
try:
self.write(repr(node.as_const(frame.eval_ctx)))
except nodes.Impossible:
self.write(
"(Markup if context.eval_ctx.autoescape else identity)(%r)" % node.data
)
def visit_Tuple(self, node, frame):
self.write("(")
idx = -1
for idx, item in enumerate(node.items):
if idx:
self.write(", ")
self.visit(item, frame)
self.write(idx == 0 and ",)" or ")")
def visit_List(self, node, frame):
self.write("[")
for idx, item in enumerate(node.items):
if idx:
self.write(", ")
self.visit(item, frame)
self.write("]")
def visit_Dict(self, node, frame):
self.write("{")
for idx, item in enumerate(node.items):
if idx:
self.write(", ")
self.visit(item.key, frame)
self.write(": ")
self.visit(item.value, frame)
self.write("}")
def binop(operator, interceptable=True): # noqa: B902
@optimizeconst
def visitor(self, node, frame):
if (
self.environment.sandboxed
and operator in self.environment.intercepted_binops
):
self.write("environment.call_binop(context, %r, " % operator)
self.visit(node.left, frame)
self.write(", ")
self.visit(node.right, frame)
else:
self.write("(")
self.visit(node.left, frame)
self.write(" %s " % operator)
self.visit(node.right, frame)
self.write(")")
return visitor
def uaop(operator, interceptable=True): # noqa: B902
@optimizeconst
def visitor(self, node, frame):
if (
self.environment.sandboxed
and operator in self.environment.intercepted_unops
):
self.write("environment.call_unop(context, %r, " % operator)
self.visit(node.node, frame)
else:
self.write("(" + operator)
self.visit(node.node, frame)
self.write(")")
return visitor
visit_Add = binop("+")
visit_Sub = binop("-")
visit_Mul = binop("*")
visit_Div = binop("/")
visit_FloorDiv = binop("//")
visit_Pow = binop("**")
visit_Mod = binop("%")
visit_And = binop("and", interceptable=False)
visit_Or = binop("or", interceptable=False)
visit_Pos = uaop("+")
visit_Neg = uaop("-")
visit_Not = uaop("not ", interceptable=False)
del binop, uaop
@optimizeconst
def visit_Concat(self, node, frame):
if frame.eval_ctx.volatile:
func_name = "(context.eval_ctx.volatile and markup_join or unicode_join)"
elif frame.eval_ctx.autoescape:
func_name = "markup_join"
else:
func_name = "unicode_join"
self.write("%s((" % func_name)
for arg in node.nodes:
self.visit(arg, frame)
self.write(", ")
self.write("))")
@optimizeconst
def visit_Compare(self, node, frame):
self.write("(")
self.visit(node.expr, frame)
for op in node.ops:
self.visit(op, frame)
self.write(")")
def visit_Operand(self, node, frame):
self.write(" %s " % operators[node.op])
self.visit(node.expr, frame)
@optimizeconst
def visit_Getattr(self, node, frame):
if self.environment.is_async:
self.write("(await auto_await(")
self.write("environment.getattr(")
self.visit(node.node, frame)
self.write(", %r)" % node.attr)
if self.environment.is_async:
self.write("))")
@optimizeconst
def visit_Getitem(self, node, frame):
# slices bypass the environment getitem method.
if isinstance(node.arg, nodes.Slice):
self.visit(node.node, frame)
self.write("[")
self.visit(node.arg, frame)
self.write("]")
else:
if self.environment.is_async:
self.write("(await auto_await(")
self.write("environment.getitem(")
self.visit(node.node, frame)
self.write(", ")
self.visit(node.arg, frame)
self.write(")")
if self.environment.is_async:
self.write("))")
def visit_Slice(self, node, frame):
if node.start is not None:
self.visit(node.start, frame)
self.write(":")
if node.stop is not None:
self.visit(node.stop, frame)
if node.step is not None:
self.write(":")
self.visit(node.step, frame)
@optimizeconst
def visit_Filter(self, node, frame):
if self.environment.is_async:
self.write("await auto_await(")
self.write(self.filters[node.name] + "(")
func = self.environment.filters.get(node.name)
if func is None:
self.fail("no filter named %r" % node.name, node.lineno)
if getattr(func, "contextfilter", False) is True:
self.write("context, ")
elif getattr(func, "evalcontextfilter", False) is True:
self.write("context.eval_ctx, ")
elif getattr(func, "environmentfilter", False) is True:
self.write("environment, ")
# if the filter node is None we are inside a filter block
# and want to write to the current buffer
if node.node is not None:
self.visit(node.node, frame)
elif frame.eval_ctx.volatile:
self.write(
"(context.eval_ctx.autoescape and"
" Markup(concat(%s)) or concat(%s))" % (frame.buffer, frame.buffer)
)
elif frame.eval_ctx.autoescape:
self.write("Markup(concat(%s))" % frame.buffer)
else:
self.write("concat(%s)" % frame.buffer)
self.signature(node, frame)
self.write(")")
if self.environment.is_async:
self.write(")")
@optimizeconst
def visit_Test(self, node, frame):
self.write(self.tests[node.name] + "(")
if node.name not in self.environment.tests:
self.fail("no test named %r" % node.name, node.lineno)
self.visit(node.node, frame)
self.signature(node, frame)
self.write(")")
@optimizeconst
def visit_CondExpr(self, node, frame):
def write_expr2():
if node.expr2 is not None:
return self.visit(node.expr2, frame)
self.write(
"cond_expr_undefined(%r)"
% (
"the inline if-"
"expression on %s evaluated to false and "
"no else section was defined." % self.position(node)
)
)
self.write("(")
self.visit(node.expr1, frame)
self.write(" if ")
self.visit(node.test, frame)
self.write(" else ")
write_expr2()
self.write(")")
@optimizeconst
def visit_Call(self, node, frame, forward_caller=False):
if self.environment.is_async:
self.write("await auto_await(")
if self.environment.sandboxed:
self.write("environment.call(context, ")
else:
self.write("context.call(")
self.visit(node.node, frame)
extra_kwargs = forward_caller and {"caller": "caller"} or None
self.signature(node, frame, extra_kwargs)
self.write(")")
if self.environment.is_async:
self.write(")")
def visit_Keyword(self, node, frame):
self.write(node.key + "=")
self.visit(node.value, frame)
# -- Unused nodes for extensions
def visit_MarkSafe(self, node, frame):
self.write("Markup(")
self.visit(node.expr, frame)
self.write(")")
def visit_MarkSafeIfAutoescape(self, node, frame):
self.write("(context.eval_ctx.autoescape and Markup or identity)(")
self.visit(node.expr, frame)
self.write(")")
def visit_EnvironmentAttribute(self, node, frame):
self.write("environment." + node.name)
def visit_ExtensionAttribute(self, node, frame):
self.write("environment.extensions[%r].%s" % (node.identifier, node.name))
def visit_ImportedName(self, node, frame):
self.write(self.import_aliases[node.importname])
def visit_InternalName(self, node, frame):
self.write(node.name)
def visit_ContextReference(self, node, frame):
self.write("context")
def visit_DerivedContextReference(self, node, frame):
self.write(self.derive_context(frame))
def visit_Continue(self, node, frame):
self.writeline("continue", node)
def visit_Break(self, node, frame):
self.writeline("break", node)
def visit_Scope(self, node, frame):
scope_frame = frame.inner()
scope_frame.symbols.analyze_node(node)
self.enter_frame(scope_frame)
self.blockvisit(node.body, scope_frame)
self.leave_frame(scope_frame)
def visit_OverlayScope(self, node, frame):
ctx = self.temporary_identifier()
self.writeline("%s = %s" % (ctx, self.derive_context(frame)))
self.writeline("%s.vars = " % ctx)
self.visit(node.context, frame)
self.push_context_reference(ctx)
scope_frame = frame.inner(isolated=True)
scope_frame.symbols.analyze_node(node)
self.enter_frame(scope_frame)
self.blockvisit(node.body, scope_frame)
self.leave_frame(scope_frame)
self.pop_context_reference()
def visit_EvalContextModifier(self, node, frame):
for keyword in node.options:
self.writeline("context.eval_ctx.%s = " % keyword.key)
self.visit(keyword.value, frame)
try:
val = keyword.value.as_const(frame.eval_ctx)
except nodes.Impossible:
frame.eval_ctx.volatile = True
else:
setattr(frame.eval_ctx, keyword.key, val)
def visit_ScopedEvalContextModifier(self, node, frame):
old_ctx_name = self.temporary_identifier()
saved_ctx = frame.eval_ctx.save()
self.writeline("%s = context.eval_ctx.save()" % old_ctx_name)
self.visit_EvalContextModifier(node, frame)
for child in node.body:
self.visit(child, frame)
frame.eval_ctx.revert(saved_ctx)
self.writeline("context.eval_ctx.revert(%s)" % old_ctx_name)
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