"""Parse tokens from the lexer into nodes for the compiler."""
import typing
import typing as t
from . import nodes
from .exceptions import TemplateAssertionError
from .exceptions import TemplateSyntaxError
from .lexer import describe_token
from .lexer import describe_token_expr
if t.TYPE_CHECKING:
import typing_extensions as te
from .environment import Environment
_ImportInclude = t.TypeVar("_ImportInclude", nodes.Import, nodes.Include)
_MacroCall = t.TypeVar("_MacroCall", nodes.Macro, nodes.CallBlock)
_statement_keywords = frozenset(
[
"for",
"if",
"block",
"extends",
"print",
"macro",
"include",
"from",
"import",
"set",
"with",
"autoescape",
]
)
_compare_operators = frozenset(["eq", "ne", "lt", "lteq", "gt", "gteq"])
_math_nodes: t.Dict[str, t.Type[nodes.Expr]] = {
"add": nodes.Add,
"sub": nodes.Sub,
"mul": nodes.Mul,
"div": nodes.Div,
"floordiv": nodes.FloorDiv,
"mod": nodes.Mod,
}
class Parser:
"""This is the central parsing class Jinja uses. It's passed to
extensions and can be used to parse expressions or statements.
"""
def __init__(
self,
environment: "Environment",
source: str,
name: t.Optional[str] = None,
filename: t.Optional[str] = None,
state: t.Optional[str] = None,
) -> None:
self.environment = environment
self.stream = environment._tokenize(source, name, filename, state)
self.name = name
self.filename = filename
self.closed = False
self.extensions: t.Dict[
str, t.Callable[["Parser"], t.Union[nodes.Node, t.List[nodes.Node]]]
] = {}
for extension in environment.iter_extensions():
for tag in extension.tags:
self.extensions[tag] = extension.parse
self._last_identifier = 0
self._tag_stack: t.List[str] = []
self._end_token_stack: t.List[t.Tuple[str, ...]] = []
def fail(
self,
msg: str,
lineno: t.Optional[int] = None,
exc: t.Type[TemplateSyntaxError] = TemplateSyntaxError,
) -> "te.NoReturn":
"""Convenience method that raises `exc` with the message, passed
line number or last line number as well as the current name and
filename.
"""
if lineno is None:
lineno = self.stream.current.lineno
raise exc(msg, lineno, self.name, self.filename)
def _fail_ut_eof(
self,
name: t.Optional[str],
end_token_stack: t.List[t.Tuple[str, ...]],
lineno: t.Optional[int],
) -> "te.NoReturn":
expected: t.Set[str] = set()
for exprs in end_token_stack:
expected.update(map(describe_token_expr, exprs))
if end_token_stack:
currently_looking: t.Optional[str] = " or ".join(
map(repr, map(describe_token_expr, end_token_stack[-1]))
)
else:
currently_looking = None
if name is None:
message = ["Unexpected end of template."]
else:
message = [f"Encountered unknown tag {name!r}."]
if currently_looking:
if name is not None and name in expected:
message.append(
"You probably made a nesting mistake. Jinja is expecting this tag,"
f" but currently looking for {currently_looking}."
)
else:
message.append(
f"Jinja was looking for the following tags: {currently_looking}."
)
if self._tag_stack:
message.append(
"The innermost block that needs to be closed is"
f" {self._tag_stack[-1]!r}."
)
self.fail(" ".join(message), lineno)
def fail_unknown_tag(
self, name: str, lineno: t.Optional[int] = None
) -> "te.NoReturn":
"""Called if the parser encounters an unknown tag. Tries to fail
with a human readable error message that could help to identify
the problem.
"""
self._fail_ut_eof(name, self._end_token_stack, lineno)
def fail_eof(
self,
end_tokens: t.Optional[t.Tuple[str, ...]] = None,
lineno: t.Optional[int] = None,
) -> "te.NoReturn":
"""Like fail_unknown_tag but for end of template situations."""
stack = list(self._end_token_stack)
if end_tokens is not None:
stack.append(end_tokens)
self._fail_ut_eof(None, stack, lineno)
def is_tuple_end(
self, extra_end_rules: t.Optional[t.Tuple[str, ...]] = None
) -> bool:
"""Are we at the end of a tuple?"""
if self.stream.current.type in ("variable_end", "block_end", "rparen"):
return True
elif extra_end_rules is not None:
return self.stream.current.test_any(extra_end_rules) # type: ignore
return False
def free_identifier(self, lineno: t.Optional[int] = None) -> nodes.InternalName:
"""Return a new free identifier as :class:`~jinja2.nodes.InternalName`."""
self._last_identifier += 1
rv = object.__new__(nodes.InternalName)
nodes.Node.__init__(rv, f"fi{self._last_identifier}", lineno=lineno)
return rv
def parse_statement(self) -> t.Union[nodes.Node, t.List[nodes.Node]]:
"""Parse a single statement."""
token = self.stream.current
if token.type != "name":
self.fail("tag name expected", token.lineno)
self._tag_stack.append(token.value)
pop_tag = True
try:
if token.value in _statement_keywords:
f = getattr(self, f"parse_{self.stream.current.value}")
return f() # type: ignore
if token.value == "call":
return self.parse_call_block()
if token.value == "filter":
return self.parse_filter_block()
ext = self.extensions.get(token.value)
if ext is not None:
return ext(self)
# did not work out, remove the token we pushed by accident
# from the stack so that the unknown tag fail function can
# produce a proper error message.
self._tag_stack.pop()
pop_tag = False
self.fail_unknown_tag(token.value, token.lineno)
finally:
if pop_tag:
self._tag_stack.pop()
def parse_statements(
self, end_tokens: t.Tuple[str, ...], drop_needle: bool = False
) -> t.List[nodes.Node]:
"""Parse multiple statements into a list until one of the end tokens
is reached. This is used to parse the body of statements as it also
parses template data if appropriate. The parser checks first if the
current token is a colon and skips it if there is one. Then it checks
for the block end and parses until if one of the `end_tokens` is
reached. Per default the active token in the stream at the end of
the call is the matched end token. If this is not wanted `drop_needle`
can be set to `True` and the end token is removed.
"""
# the first token may be a colon for python compatibility
self.stream.skip_if("colon")
# in the future it would be possible to add whole code sections
# by adding some sort of end of statement token and parsing those here.
self.stream.expect("block_end")
result = self.subparse(end_tokens)
# we reached the end of the template too early, the subparser
# does not check for this, so we do that now
if self.stream.current.type == "eof":
self.fail_eof(end_tokens)
if drop_needle:
next(self.stream)
return result
def parse_set(self) -> t.Union[nodes.Assign, nodes.AssignBlock]:
"""Parse an assign statement."""
lineno = next(self.stream).lineno
target = self.parse_assign_target(with_namespace=True)
if self.stream.skip_if("assign"):
expr = self.parse_tuple()
return nodes.Assign(target, expr, lineno=lineno)
filter_node = self.parse_filter(None)
body = self.parse_statements(("name:endset",), drop_needle=True)
return nodes.AssignBlock(target, filter_node, body, lineno=lineno)
def parse_for(self) -> nodes.For:
"""Parse a for loop."""
lineno = self.stream.expect("name:for").lineno
target = self.parse_assign_target(extra_end_rules=("name:in",))
self.stream.expect("name:in")
iter = self.parse_tuple(
with_condexpr=False, extra_end_rules=("name:recursive",)
)
test = None
if self.stream.skip_if("name:if"):
test = self.parse_expression()
recursive = self.stream.skip_if("name:recursive")
body = self.parse_statements(("name:endfor", "name:else"))
if next(self.stream).value == "endfor":
else_ = []
else:
else_ = self.parse_statements(("name:endfor",), drop_needle=True)
return nodes.For(target, iter, body, else_, test, recursive, lineno=lineno)
def parse_if(self) -> nodes.If:
"""Parse an if construct."""
node = result = nodes.If(lineno=self.stream.expect("name:if").lineno)
while True:
node.test = self.parse_tuple(with_condexpr=False)
node.body = self.parse_statements(("name:elif", "name:else", "name:endif"))
node.elif_ = []
node.else_ = []
token = next(self.stream)
if token.test("name:elif"):
node = nodes.If(lineno=self.stream.current.lineno)
result.elif_.append(node)
continue
elif token.test("name:else"):
result.else_ = self.parse_statements(("name:endif",), drop_needle=True)
break
return result
def parse_with(self) -> nodes.With:
node = nodes.With(lineno=next(self.stream).lineno)
targets: t.List[nodes.Expr] = []
values: t.List[nodes.Expr] = []
while self.stream.current.type != "block_end":
if targets:
self.stream.expect("comma")
target = self.parse_assign_target()
target.set_ctx("param")
targets.append(target)
self.stream.expect("assign")
values.append(self.parse_expression())
node.targets = targets
node.values = values
node.body = self.parse_statements(("name:endwith",), drop_needle=True)
return node
def parse_autoescape(self) -> nodes.Scope:
node = nodes.ScopedEvalContextModifier(lineno=next(self.stream).lineno)
node.options = [nodes.Keyword("autoescape", self.parse_expression())]
node.body = self.parse_statements(("name:endautoescape",), drop_needle=True)
return nodes.Scope([node])
def parse_block(self) -> nodes.Block:
node = nodes.Block(lineno=next(self.stream).lineno)
node.name = self.stream.expect("name").value
node.scoped = self.stream.skip_if("name:scoped")
node.required = self.stream.skip_if("name:required")
# common problem people encounter when switching from django
# to jinja. we do not support hyphens in block names, so let's
# raise a nicer error message in that case.
if self.stream.current.type == "sub":
self.fail(
"Block names in Jinja have to be valid Python identifiers and may not"
" contain hyphens, use an underscore instead."
)
node.body = self.parse_statements(("name:endblock",), drop_needle=True)
# enforce that required blocks only contain whitespace or comments
# by asserting that the body, if not empty, is just TemplateData nodes
# with whitespace data
if node.required and not all(
isinstance(child, nodes.TemplateData) and child.data.isspace()
for body in node.body
for child in body.nodes # type: ignore
):
self.fail("Required blocks can only contain comments or whitespace")
self.stream.skip_if("name:" + node.name)
return node
def parse_extends(self) -> nodes.Extends:
node = nodes.Extends(lineno=next(self.stream).lineno)
node.template = self.parse_expression()
return node
def parse_import_context(
self, node: _ImportInclude, default: bool
) -> _ImportInclude:
if self.stream.current.test_any(
"name:with", "name:without"
) and self.stream.look().test("name:context"):
node.with_context = next(self.stream).value == "with"
self.stream.skip()
else:
node.with_context = default
return node
def parse_include(self) -> nodes.Include:
node = nodes.Include(lineno=next(self.stream).lineno)
node.template = self.parse_expression()
if self.stream.current.test("name:ignore") and self.stream.look().test(
"name:missing"
):
node.ignore_missing = True
self.stream.skip(2)
else:
node.ignore_missing = False
return self.parse_import_context(node, True)
def parse_import(self) -> nodes.Import:
node = nodes.Import(lineno=next(self.stream).lineno)
node.template = self.parse_expression()
self.stream.expect("name:as")
node.target = self.parse_assign_target(name_only=True).name
return self.parse_import_context(node, False)
def parse_from(self) -> nodes.FromImport:
node = nodes.FromImport(lineno=next(self.stream).lineno)
node.template = self.parse_expression()
self.stream.expect("name:import")
node.names = []
def parse_context() -> bool:
if self.stream.current.value in {
"with",
"without",
} and self.stream.look().test("name:context"):
node.with_context = next(self.stream).value == "with"
self.stream.skip()
return True
return False
while True:
if node.names:
self.stream.expect("comma")
if self.stream.current.type == "name":
if parse_context():
break
target = self.parse_assign_target(name_only=True)
if target.name.startswith("_"):
self.fail(
"names starting with an underline can not be imported",
target.lineno,
exc=TemplateAssertionError,
)
if self.stream.skip_if("name:as"):
alias = self.parse_assign_target(name_only=True)
node.names.append((target.name, alias.name))
else:
node.names.append(target.name)
if parse_context() or self.stream.current.type != "comma":
break
else:
self.stream.expect("name")
if not hasattr(node, "with_context"):
node.with_context = False
return node
def parse_signature(self, node: _MacroCall) -> None:
args = node.args = []
defaults = node.defaults = []
self.stream.expect("lparen")
while self.stream.current.type != "rparen":
if args:
self.stream.expect("comma")
arg = self.parse_assign_target(name_only=True)
arg.set_ctx("param")
if self.stream.skip_if("assign"):
defaults.append(self.parse_expression())
elif defaults:
self.fail("non-default argument follows default argument")
args.append(arg)
self.stream.expect("rparen")
def parse_call_block(self) -> nodes.CallBlock:
node = nodes.CallBlock(lineno=next(self.stream).lineno)
if self.stream.current.type == "lparen":
self.parse_signature(node)
else:
node.args = []
node.defaults = []
call_node = self.parse_expression()
if not isinstance(call_node, nodes.Call):
self.fail("expected call", node.lineno)
node.call = call_node
node.body = self.parse_statements(("name:endcall",), drop_needle=True)
return node
def parse_filter_block(self) -> nodes.FilterBlock:
node = nodes.FilterBlock(lineno=next(self.stream).lineno)
node.filter = self.parse_filter(None, start_inline=True) # type: ignore
node.body = self.parse_statements(("name:endfilter",), drop_needle=True)
return node
def parse_macro(self) -> nodes.Macro:
node = nodes.Macro(lineno=next(self.stream).lineno)
node.name = self.parse_assign_target(name_only=True).name
self.parse_signature(node)
node.body = self.parse_statements(("name:endmacro",), drop_needle=True)
return node
def parse_print(self) -> nodes.Output:
node = nodes.Output(lineno=next(self.stream).lineno)
node.nodes = []
while self.stream.current.type != "block_end":
if node.nodes:
self.stream.expect("comma")
node.nodes.append(self.parse_expression())
return node
@typing.overload
def parse_assign_target(
self, with_tuple: bool = ..., name_only: "te.Literal[True]" = ...
) -> nodes.Name:
...
@typing.overload
def parse_assign_target(
self,
with_tuple: bool = True,
name_only: bool = False,
extra_end_rules: t.Optional[t.Tuple[str, ...]] = None,
with_namespace: bool = False,
) -> t.Union[nodes.NSRef, nodes.Name, nodes.Tuple]:
...
def parse_assign_target(
self,
with_tuple: bool = True,
name_only: bool = False,
extra_end_rules: t.Optional[t.Tuple[str, ...]] = None,
with_namespace: bool = False,
) -> t.Union[nodes.NSRef, nodes.Name, nodes.Tuple]:
"""Parse an assignment target. As Jinja allows assignments to
tuples, this function can parse all allowed assignment targets. Per
default assignments to tuples are parsed, that can be disable however
by setting `with_tuple` to `False`. If only assignments to names are
wanted `name_only` can be set to `True`. The `extra_end_rules`
parameter is forwarded to the tuple parsing function. If
`with_namespace` is enabled, a namespace assignment may be parsed.
"""
target: nodes.Expr
if with_namespace and self.stream.look().type == "dot":
token = self.stream.expect("name")
next(self.stream) # dot
attr = self.stream.expect("name")
target = nodes.NSRef(token.value, attr.value, lineno=token.lineno)
elif name_only:
token = self.stream.expect("name")
target = nodes.Name(token.value, "store", lineno=token.lineno)
else:
if with_tuple:
target = self.parse_tuple(
simplified=True, extra_end_rules=extra_end_rules
)
else:
target = self.parse_primary()
target.set_ctx("store")
if not target.can_assign():
self.fail(
f"can't assign to {type(target).__name__.lower()!r}", target.lineno
)
return target # type: ignore
def parse_expression(self, with_condexpr: bool = True) -> nodes.Expr:
"""Parse an expression. Per default all expressions are parsed, if
the optional `with_condexpr` parameter is set to `False` conditional
expressions are not parsed.
"""
if with_condexpr:
return self.parse_condexpr()
return self.parse_or()
def parse_condexpr(self) -> nodes.Expr:
lineno = self.stream.current.lineno
expr1 = self.parse_or()
expr3: t.Optional[nodes.Expr]
while self.stream.skip_if("name:if"):
expr2 = self.parse_or()
if self.stream.skip_if("name:else"):
expr3 = self.parse_condexpr()
else:
expr3 = None
expr1 = nodes.CondExpr(expr2, expr1, expr3, lineno=lineno)
lineno = self.stream.current.lineno
return expr1
def parse_or(self) -> nodes.Expr:
lineno = self.stream.current.lineno
left = self.parse_and()
while self.stream.skip_if("name:or"):
right = self.parse_and()
left = nodes.Or(left, right, lineno=lineno)
lineno = self.stream.current.lineno
return left
def parse_and(self) -> nodes.Expr:
lineno = self.stream.current.lineno
left = self.parse_not()
while self.stream.skip_if("name:and"):
right = self.parse_not()
left = nodes.And(left, right, lineno=lineno)
lineno = self.stream.current.lineno
return left
def parse_not(self) -> nodes.Expr:
if self.stream.current.test("name:not"):
lineno = next(self.stream).lineno
return nodes.Not(self.parse_not(), lineno=lineno)
return self.parse_compare()
def parse_compare(self) -> nodes.Expr:
lineno = self.stream.current.lineno
expr = self.parse_math1()
ops = []
while True:
token_type = self.stream.current.type
if token_type in _compare_operators:
next(self.stream)
ops.append(nodes.Operand(token_type, self.parse_math1()))
elif self.stream.skip_if("name:in"):
ops.append(nodes.Operand("in", self.parse_math1()))
elif self.stream.current.test("name:not") and self.stream.look().test(
"name:in"
):
self.stream.skip(2)
ops.append(nodes.Operand("notin", self.parse_math1()))
else:
break
lineno = self.stream.current.lineno
if not ops:
return expr
return nodes.Compare(expr, ops, lineno=lineno)
def parse_math1(self) -> nodes.Expr:
lineno = self.stream.current.lineno
left = self.parse_concat()
while self.stream.current.type in ("add", "sub"):
cls = _math_nodes[self.stream.current.type]
next(self.stream)
right = self.parse_concat()
left = cls(left, right, lineno=lineno)
lineno = self.stream.current.lineno
return left
def parse_concat(self) -> nodes.Expr:
lineno = self.stream.current.lineno
args = [self.parse_math2()]
while self.stream.current.type == "tilde":
next(self.stream)
args.append(self.parse_math2())
if len(args) == 1:
return args[0]
return nodes.Concat(args, lineno=lineno)
def parse_math2(self) -> nodes.Expr:
lineno = self.stream.current.lineno
left = self.parse_pow()
while self.stream.current.type in ("mul", "div", "floordiv", "mod"):
cls = _math_nodes[self.stream.current.type]
next(self.stream)
right = self.parse_pow()
left = cls(left, right, lineno=lineno)
lineno = self.stream.current.lineno
return left
def parse_pow(self) -> nodes.Expr:
lineno = self.stream.current.lineno
left = self.parse_unary()
while self.stream.current.type == "pow":
next(self.stream)
right = self.parse_unary()
left = nodes.Pow(left, right, lineno=lineno)
lineno = self.stream.current.lineno
return left
def parse_unary(self, with_filter: bool = True) -> nodes.Expr:
token_type = self.stream.current.type
lineno = self.stream.current.lineno
node: nodes.Expr
if token_type == "sub":
next(self.stream)
node = nodes.Neg(self.parse_unary(False), lineno=lineno)
elif token_type == "add":
next(self.stream)
node = nodes.Pos(self.parse_unary(False), lineno=lineno)
else:
node = self.parse_primary()
node = self.parse_postfix(node)
if with_filter:
node = self.parse_filter_expr(node)
return node
def parse_primary(self) -> nodes.Expr:
token = self.stream.current
node: nodes.Expr
if token.type == "name":
if token.value in ("true", "false", "True", "False"):
node = nodes.Const(token.value in ("true", "True"), lineno=token.lineno)
elif token.value in ("none", "None"):
node = nodes.Const(None, lineno=token.lineno)
else:
node = nodes.Name(token.value, "load", lineno=token.lineno)
next(self.stream)
elif token.type == "string":
next(self.stream)
buf = [token.value]
lineno = token.lineno
while self.stream.current.type == "string":
buf.append(self.stream.current.value)
next(self.stream)
node = nodes.Const("".join(buf), lineno=lineno)
elif token.type in ("integer", "float"):
next(self.stream)
node = nodes.Const(token.value, lineno=token.lineno)
elif token.type == "lparen":
next(self.stream)
node = self.parse_tuple(explicit_parentheses=True)
self.stream.expect("rparen")
elif token.type == "lbracket":
node = self.parse_list()
elif token.type == "lbrace":
node = self.parse_dict()
else:
self.fail(f"unexpected {describe_token(token)!r}", token.lineno)
return node
def parse_tuple(
self,
simplified: bool = False,
with_condexpr: bool = True,
extra_end_rules: t.Optional[t.Tuple[str, ...]] = None,
explicit_parentheses: bool = False,
) -> t.Union[nodes.Tuple, nodes.Expr]:
"""Works like `parse_expression` but if multiple expressions are
delimited by a comma a :class:`~jinja2.nodes.Tuple` node is created.
This method could also return a regular expression instead of a tuple
if no commas where found.
The default parsing mode is a full tuple. If `simplified` is `True`
only names and literals are parsed. The `no_condexpr` parameter is
forwarded to :meth:`parse_expression`.
Because tuples do not require delimiters and may end in a bogus comma
an extra hint is needed that marks the end of a tuple. For example
for loops support tuples between `for` and `in`. In that case the
`extra_end_rules` is set to ``['name:in']``.
`explicit_parentheses` is true if the parsing was triggered by an
expression in parentheses. This is used to figure out if an empty
tuple is a valid expression or not.
"""
lineno = self.stream.current.lineno
if simplified:
parse = self.parse_primary
elif with_condexpr:
parse = self.parse_expression
else:
def parse() -> nodes.Expr:
return self.parse_expression(with_condexpr=False)
args: t.List[nodes.Expr] = []
is_tuple = False
while True:
if args:
self.stream.expect("comma")
if self.is_tuple_end(extra_end_rules):
break
args.append(parse())
if self.stream.current.type == "comma":
is_tuple = True
else:
break
lineno = self.stream.current.lineno
if not is_tuple:
if args:
return args[0]
# if we don't have explicit parentheses, an empty tuple is
# not a valid expression. This would mean nothing (literally
# nothing) in the spot of an expression would be an empty
# tuple.
if not explicit_parentheses:
self.fail(
"Expected an expression,"
f" got {describe_token(self.stream.current)!r}"
)
return nodes.Tuple(args, "load", lineno=lineno)
def parse_list(self) -> nodes.List:
token = self.stream.expect("lbracket")
items: t.List[nodes.Expr] = []
while self.stream.current.type != "rbracket":
if items:
self.stream.expect("comma")
if self.stream.current.type == "rbracket":
break
items.append(self.parse_expression())
self.stream.expect("rbracket")
return nodes.List(items, lineno=token.lineno)
def parse_dict(self) -> nodes.Dict:
token = self.stream.expect("lbrace")
items: t.List[nodes.Pair] = []
while self.stream.current.type != "rbrace":
if items:
self.stream.expect("comma")
if self.stream.current.type == "rbrace":
break
key = self.parse_expression()
self.stream.expect("colon")
value = self.parse_expression()
items.append(nodes.Pair(key, value, lineno=key.lineno))
self.stream.expect("rbrace")
return nodes.Dict(items, lineno=token.lineno)
def parse_postfix(self, node: nodes.Expr) -> nodes.Expr:
while True:
token_type = self.stream.current.type
if token_type == "dot" or token_type == "lbracket":
node = self.parse_subscript(node)
# calls are valid both after postfix expressions (getattr
# and getitem) as well as filters and tests
elif token_type == "lparen":
node = self.parse_call(node)
else:
break
return node
def parse_filter_expr(self, node: nodes.Expr) -> nodes.Expr:
while True:
token_type = self.stream.current.type
if token_type == "pipe":
node = self.parse_filter(node) # type: ignore
elif token_type == "name" and self.stream.current.value == "is":
node = self.parse_test(node)
# calls are valid both after postfix expressions (getattr
# and getitem) as well as filters and tests
elif token_type == "lparen":
node = self.parse_call(node)
else:
break
return node
def parse_subscript(
self, node: nodes.Expr
) -> t.Union[nodes.Getattr, nodes.Getitem]:
token = next(self.stream)
arg: nodes.Expr
if token.type == "dot":
attr_token = self.stream.current
next(self.stream)
if attr_token.type == "name":
return nodes.Getattr(
node, attr_token.value, "load", lineno=token.lineno
)
elif attr_token.type != "integer":
self.fail("expected name or number", attr_token.lineno)
arg = nodes.Const(attr_token.value, lineno=attr_token.lineno)
return nodes.Getitem(node, arg, "load", lineno=token.lineno)
if token.type == "lbracket":
args: t.List[nodes.Expr] = []
while self.stream.current.type != "rbracket":
if args:
self.stream.expect("comma")
args.append(self.parse_subscribed())
self.stream.expect("rbracket")
if len(args) == 1:
arg = args[0]
else:
arg = nodes.Tuple(args, "load", lineno=token.lineno)
return nodes.Getitem(node, arg, "load", lineno=token.lineno)
self.fail("expected subscript expression", token.lineno)
def parse_subscribed(self) -> nodes.Expr:
lineno = self.stream.current.lineno
args: t.List[t.Optional[nodes.Expr]]
if self.stream.current.type == "colon":
next(self.stream)
args = [None]
else:
node = self.parse_expression()
if self.stream.current.type != "colon":
return node
next(self.stream)
args = [node]
if self.stream.current.type == "colon":
args.append(None)
elif self.stream.current.type not in ("rbracket", "comma"):
args.append(self.parse_expression())
else:
args.append(None)
if self.stream.current.type == "colon":
next(self.stream)
if self.stream.current.type not in ("rbracket", "comma"):
args.append(self.parse_expression())
else:
args.append(None)
else:
args.append(None)
return nodes.Slice(lineno=lineno, *args)
def parse_call_args(self) -> t.Tuple:
token = self.stream.expect("lparen")
args = []
kwargs = []
dyn_args = None
dyn_kwargs = None
require_comma = False
def ensure(expr: bool) -> None:
if not expr:
self.fail("invalid syntax for function call expression", token.lineno)
while self.stream.current.type != "rparen":
if require_comma:
self.stream.expect("comma")
# support for trailing comma
if self.stream.current.type == "rparen":
break
if self.stream.current.type == "mul":
ensure(dyn_args is None and dyn_kwargs is None)
next(self.stream)
dyn_args = self.parse_expression()
elif self.stream.current.type == "pow":
ensure(dyn_kwargs is None)
next(self.stream)
dyn_kwargs = self.parse_expression()
else:
if (
self.stream.current.type == "name"
and self.stream.look().type == "assign"
):
# Parsing a kwarg
ensure(dyn_kwargs is None)
key = self.stream.current.value
self.stream.skip(2)
value = self.parse_expression()
kwargs.append(nodes.Keyword(key, value, lineno=value.lineno))
else:
# Parsing an arg
ensure(dyn_args is None and dyn_kwargs is None and not kwargs)
args.append(self.parse_expression())
require_comma = True
self.stream.expect("rparen")
return args, kwargs, dyn_args, dyn_kwargs
def parse_call(self, node: nodes.Expr) -> nodes.Call:
# The lparen will be expected in parse_call_args, but the lineno
# needs to be recorded before the stream is advanced.
token = self.stream.current
args, kwargs, dyn_args, dyn_kwargs = self.parse_call_args()
return nodes.Call(node, args, kwargs, dyn_args, dyn_kwargs, lineno=token.lineno)
def parse_filter(
self, node: t.Optional[nodes.Expr], start_inline: bool = False
) -> t.Optional[nodes.Expr]:
while self.stream.current.type == "pipe" or start_inline:
if not start_inline:
next(self.stream)
token = self.stream.expect("name")
name = token.value
while self.stream.current.type == "dot":
next(self.stream)
name += "." + self.stream.expect("name").value
if self.stream.current.type == "lparen":
args, kwargs, dyn_args, dyn_kwargs = self.parse_call_args()
else:
args = []
kwargs = []
dyn_args = dyn_kwargs = None
node = nodes.Filter(
node, name, args, kwargs, dyn_args, dyn_kwargs, lineno=token.lineno
)
start_inline = False
return node
def parse_test(self, node: nodes.Expr) -> nodes.Expr:
token = next(self.stream)
if self.stream.current.test("name:not"):
next(self.stream)
negated = True
else:
negated = False
name = self.stream.expect("name").value
while self.stream.current.type == "dot":
next(self.stream)
name += "." + self.stream.expect("name").value
dyn_args = dyn_kwargs = None
kwargs = []
if self.stream.current.type == "lparen":
args, kwargs, dyn_args, dyn_kwargs = self.parse_call_args()
elif self.stream.current.type in {
"name",
"string",
"integer",
"float",
"lparen",
"lbracket",
"lbrace",
} and not self.stream.current.test_any("name:else", "name:or", "name:and"):
if self.stream.current.test("name:is"):
self.fail("You cannot chain multiple tests with is")
arg_node = self.parse_primary()
arg_node = self.parse_postfix(arg_node)
args = [arg_node]
else:
args = []
node = nodes.Test(
node, name, args, kwargs, dyn_args, dyn_kwargs, lineno=token.lineno
)
if negated:
node = nodes.Not(node, lineno=token.lineno)
return node
def subparse(
self, end_tokens: t.Optional[t.Tuple[str, ...]] = None
) -> t.List[nodes.Node]:
body: t.List[nodes.Node] = []
data_buffer: t.List[nodes.Node] = []
add_data = data_buffer.append
if end_tokens is not None:
self._end_token_stack.append(end_tokens)
def flush_data() -> None:
if data_buffer:
lineno = data_buffer[0].lineno
body.append(nodes.Output(data_buffer[:], lineno=lineno))
del data_buffer[:]
try:
while self.stream:
token = self.stream.current
if token.type == "data":
if token.value:
add_data(nodes.TemplateData(token.value, lineno=token.lineno))
next(self.stream)
elif token.type == "variable_begin":
next(self.stream)
add_data(self.parse_tuple(with_condexpr=True))
self.stream.expect("variable_end")
elif token.type == "block_begin":
flush_data()
next(self.stream)
if end_tokens is not None and self.stream.current.test_any(
*end_tokens
):
return body
rv = self.parse_statement()
if isinstance(rv, list):
body.extend(rv)
else:
body.append(rv)
self.stream.expect("block_end")
else:
raise AssertionError("internal parsing error")
flush_data()
finally:
if end_tokens is not None:
self._end_token_stack.pop()
return body
def parse(self) -> nodes.Template:
"""Parse the whole template into a `Template` node."""
result = nodes.Template(self.subparse(), lineno=1)
result.set_environment(self.environment)
return result
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