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Diffstat (limited to 'src/jinja2/compiler.py')
| -rw-r--r-- | src/jinja2/compiler.py | 1754 |
1 files changed, 1754 insertions, 0 deletions
diff --git a/src/jinja2/compiler.py b/src/jinja2/compiler.py new file mode 100644 index 00000000..abdbe6da --- /dev/null +++ b/src/jinja2/compiler.py @@ -0,0 +1,1754 @@ +"""Compiles nodes from the parser into Python code.""" +from collections import namedtuple +from functools import update_wrapper +from io import StringIO +from itertools import chain +from keyword import iskeyword as is_python_keyword + +from markupsafe import escape +from markupsafe import Markup + +from . import nodes +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", +} + + +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, str, Markup}: + return True + + if type(value) in {tuple, list, set, frozenset}: + return all(has_safe_repr(v) for v in value) + + if type(value) is dict: + return all(has_safe_repr(k) and has_safe_repr(v) for k, v in value.items()) + + 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: + def __init__(self, node): + self.node = node + self.accesses_caller = False + self.accesses_kwargs = False + self.accesses_varargs = False + + +class Frame: + """Holds compile time information for us.""" + + def __init__(self, eval_ctx, parent=None, level=None): + self.eval_ctx = eval_ctx + self.symbols = Symbols(parent.symbols if parent else 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.block if parent else 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 = StringIO() + 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 f"t_{self._last_identifier}" + + def buffer(self, frame): + """Enable buffering for the frame from that point onwards.""" + frame.buffer = self.temporary_identifier() + self.writeline(f"{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(f"return Markup(concat({frame.buffer}))") + self.outdent() + self.writeline("else:") + self.indent() + self.writeline(f"return concat({frame.buffer})") + self.outdent() + return + elif frame.eval_ctx.autoescape: + self.writeline(f"return Markup(concat({frame.buffer}))") + return + self.writeline(f"return concat({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(f"{frame.buffer}.append(", 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 extra_kwargs.items(): + self.write(f", {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(f"{kwarg.key!r}: ") + self.visit(kwarg.value, frame) + self.write(", ") + if extra_kwargs is not None: + for key, value in extra_kwargs.items(): + self.write(f"{key!r}: {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(f"{mapping[name]} = environment.{dependency}[{name!r}]") + + def enter_frame(self, frame): + undefs = [] + for target, (action, param) in frame.symbols.loads.items(): + if action == VAR_LOAD_PARAMETER: + pass + elif action == VAR_LOAD_RESOLVE: + self.writeline(f"{target} = {self.get_resolve_func()}({param!r})") + elif action == VAR_LOAD_ALIAS: + self.writeline(f"{target} = {param}") + elif action == VAR_LOAD_UNDEFINED: + undefs.append(target) + else: + raise NotImplementedError("unknown load instruction") + if undefs: + self.writeline(f"{' = '.join(undefs)} = missing") + + def leave_frame(self, frame, with_python_scope=False): + if not with_python_scope: + undefs = [] + for target in frame.symbols.loads: + undefs.append(target) + if undefs: + self.writeline(f"{' = '.join(undefs)} = missing") + + def func(self, name): + if self.environment.is_async: + return f"async def {name}" + return f"def {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(f"{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(f"if {ref} is missing:") + self.indent() + try: + default = node.defaults[idx - len(node.args)] + except IndexError: + self.writeline( + f'{ref} = undefined("parameter {arg.name!r} was not provided",' + f" name={arg.name!r})" + ) + else: + self.writeline(f"{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( + f"Macro(environment, macro, {name!r}, ({arg_tuple})," + f" {macro_ref.accesses_kwargs!r}, {macro_ref.accesses_varargs!r}," + f" {macro_ref.accesses_caller!r}, context.eval_ctx.autoescape)" + ) + + def position(self, node): + """Return a human readable position for the node.""" + rv = f"line {node.lineno}" + if self.name is not None: + rv = f"{rv} in {self.name!r}" + return rv + + def dump_local_context(self, frame): + items_kv = ", ".join( + f"{name!r}: {target}" + for name, target in frame.symbols.dump_stores().items() + ) + return f"{{{items_kv}}}" + + 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 f"{target}.resolve" + + def derive_context(self, frame): + return f"{self.get_context_ref()}.derived({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(f"context.vars[{name!r}] = {ref}") + else: + self.writeline("context.vars.update({") + for idx, name in enumerate(vars): + if idx: + self.write(", ") + ref = frame.symbols.ref(name) + self.write(f"{name!r}: {ref}") + self.write("})") + if public_names: + if len(public_names) == 1: + self.writeline(f"context.exported_vars.add({public_names[0]!r})") + else: + names_str = ", ".join(map(repr, public_names)) + self.writeline(f"context.exported_vars.update(({names_str}))") + + # -- 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 generator_stop") # Python < 3.7 + 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 = "" if self.defer_init else ", environment=environment" + + # 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(f"block {block.name!r} defined twice", 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(f"from {module} import {obj} as {alias}") + else: + self.writeline(f"import {imp} as {alias}") + + # add the load name + self.writeline(f"name = {self.name!r}") + + # generate the root render function. + self.writeline( + f"{self.func('root')}(context, missing=missing{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(f"{ref} = TemplateReference(context)") + 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 not self.environment.is_async: + self.writeline("yield from parent_template.root_render_func(context)") + else: + loop = "async for" if self.environment.is_async else "for" + self.writeline( + f"{loop} event in parent_template.root_render_func(context):" + ) + 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 self.blocks.items(): + self.writeline( + f"{self.func('block_' + name)}(context, missing=missing{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(f"{ref} = TemplateReference(context)") + if "super" in undeclared: + ref = block_frame.symbols.declare_parameter("super") + self.writeline(f"{ref} = context.super({name!r}, block_{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() + + blocks_kv_str = ", ".join(f"{x!r}: block_{x}" for x in self.blocks) + self.writeline(f"blocks = {{{blocks_kv_str}}}", extra=1) + debug_kv_str = "&".join(f"{k}={v}" for k, v in self.debug_info) + self.writeline(f"debug_info = {debug_kv_str!r}") + + 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 not self.environment.is_async and frame.buffer is None: + self.writeline( + f"yield from context.blocks[{node.name!r}][0]({context})", node + ) + else: + loop = "async for" if self.environment.is_async else "for" + self.writeline( + f"{loop} event in context.blocks[{node.name!r}][0]({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("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(f", {self.name!r})") + self.writeline("for name, parent_block in parent_template.blocks.items():") + 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, str): + 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(f"template = environment.{func_name}(", node) + self.visit(node.template, frame) + self.write(f", {self.name!r})") + 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 = "async for" if self.environment.is_async else "for" + self.writeline( + f"{loop} event in template.root_render_func(" + "template.new_context(context.get_all(), True," + f" {self.dump_local_context(frame)})):" + ) + elif self.environment.is_async: + self.writeline( + "for event in (await template._get_default_module_async())" + "._body_stream:" + ) + else: + self.writeline("yield from template._get_default_module()._body_stream") + skip_event_yield = True + + 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(f"{frame.symbols.ref(node.target)} = ", node) + if frame.toplevel: + self.write(f"context.vars[{node.target!r}] = ") + if self.environment.is_async: + self.write("await ") + self.write("environment.get_template(") + self.visit(node.template, frame) + self.write(f", {self.name!r}).") + if node.with_context: + func = "make_module" + ("_async" if self.environment.is_async else "") + self.write( + f"{func}(context.get_all(), True, {self.dump_local_context(frame)})" + ) + elif self.environment.is_async: + self.write("_get_default_module_async()") + else: + self.write("_get_default_module(context)") + if frame.toplevel and not node.target.startswith("_"): + self.writeline(f"context.exported_vars.discard({node.target!r})") + + def visit_FromImport(self, node, frame): + """Visit named imports.""" + self.newline(node) + prefix = "await " if self.environment.is_async else "" + self.write(f"included_template = {prefix}environment.get_template(") + self.visit(node.template, frame) + self.write(f", {self.name!r}).") + if node.with_context: + func = "make_module" + ("_async" if self.environment.is_async else "") + self.write( + f"{func}(context.get_all(), True, {self.dump_local_context(frame)})" + ) + elif self.environment.is_async: + self.write("_get_default_module_async()") + else: + self.write("_get_default_module(context)") + + var_names = [] + discarded_names = [] + for name in node.names: + if isinstance(name, tuple): + name, alias = name + else: + alias = name + self.writeline( + f"{frame.symbols.ref(alias)} =" + f" getattr(included_template, {name!r}, missing)" + ) + self.writeline(f"if {frame.symbols.ref(alias)} is missing:") + self.indent() + message = ( + "the template {included_template.__name__!r}" + f" (imported on {self.position(node)})" + f" does not export the requested name {name!r}" + ) + self.writeline( + f"{frame.symbols.ref(alias)} = undefined(f{message!r}, name={name!r})" + ) + 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(f"context.vars[{name!r}] = {frame.symbols.ref(name)}") + else: + names_kv = ", ".join( + f"{name!r}: {frame.symbols.ref(name)}" for name in var_names + ) + self.writeline(f"context.vars.update({{{names_kv}}})") + if discarded_names: + if len(discarded_names) == 1: + self.writeline(f"context.exported_vars.discard({discarded_names[0]!r})") + else: + names_str = ", ".join(map(repr, discarded_names)) + self.writeline( + f"context.exported_vars.difference_update(({names_str}))" + ) + + 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(f"{self.func(loop_filter_func)}(fiter):", node.test) + self.indent() + self.enter_frame(test_frame) + self.writeline("async for " if self.environment.is_async else "for ") + self.visit(node.target, loop_frame) + self.write(" in ") + self.write("auto_aiter(fiter)" if self.environment.is_async else "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( + f"{self.func('loop')}(reciter, loop_render_func, depth=0):", 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(f"{loop_ref} = missing") + + 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(f"{iteration_indicator} = 1") + + self.writeline("async for " if self.environment.is_async else "for ", node) + self.visit(node.target, loop_frame) + if extended_loop: + prefix = "Async" if self.environment.is_async else "" + self.write(f", {loop_ref} in {prefix}LoopContext(") + else: + self.write(" in ") + + if node.test: + self.write(f"{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(", undefined):" if extended_loop else ":") + + self.indent() + self.enter_frame(loop_frame) + + self.blockvisit(node.body, loop_frame) + if node.else_: + self.writeline(f"{iteration_indicator} = 0") + self.outdent() + self.leave_frame( + loop_frame, with_python_scope=node.recursive and not node.else_ + ) + + if node.else_: + self.writeline(f"if {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(f"context.exported_vars.add({node.name!r})") + self.writeline(f"context.vars[{node.name!r}] = ") + self.write(f"{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 zip(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 = str + _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 str(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 str)(") + elif frame.eval_ctx.autoescape: + self.write("escape(") + else: + self.write("str(") + + 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(f"{frame.buffer}.append(") + else: + self.writeline(f"{frame.buffer}.extend((") + + 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(f"concat({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( + f"(undefined(name={node.name!r}) if {ref} is missing else {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(f"if not isinstance({ref}, Namespace):") + self.indent() + self.writeline( + "raise TemplateRuntimeError" + '("cannot assign attribute on non-namespace object")' + ) + self.outdent() + self.writeline(f"{ref}[{node.attr!r}]") + + 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( + f"(Markup if context.eval_ctx.autoescape else identity)({node.data!r})" + ) + + 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(",)" if idx == 0 else ")") + + 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(f"environment.call_binop(context, {operator!r}, ") + self.visit(node.left, frame) + self.write(", ") + self.visit(node.right, frame) + else: + self.write("(") + self.visit(node.left, frame) + self.write(f" {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(f"environment.call_unop(context, {operator!r}, ") + 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 = "(markup_join if context.eval_ctx.volatile else str_join)" + elif frame.eval_ctx.autoescape: + func_name = "markup_join" + else: + func_name = "str_join" + self.write(f"{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(f" {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(f", {node.attr!r})") + + 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(f"no filter named {node.name!r}", 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( + f"(Markup(concat({frame.buffer}))" + f" if context.eval_ctx.autoescape else concat({frame.buffer}))" + ) + elif frame.eval_ctx.autoescape: + self.write(f"Markup(concat({frame.buffer}))") + else: + self.write(f"concat({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(f"no test named {node.name!r}", 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( + f'cond_expr_undefined("the inline if-expression on' + f" {self.position(node)} evaluated to false and no else" + f' section was defined.")' + ) + + 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 = {"caller": "caller"} if forward_caller else 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("(Markup if context.eval_ctx.autoescape else 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(f"environment.extensions[{node.identifier!r}].{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(f"{ctx} = {self.derive_context(frame)}") + self.writeline(f"{ctx}.vars = ") + 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(f"context.eval_ctx.{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(f"{old_ctx_name} = context.eval_ctx.save()") + self.visit_EvalContextModifier(node, frame) + for child in node.body: + self.visit(child, frame) + frame.eval_ctx.revert(saved_ctx) + self.writeline(f"context.eval_ctx.revert({old_ctx_name})") |