two version of R2R are here HEAD master

1 files changed, 870 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/jinja2/ext.py b/.venv/lib/python3.12/site-packages/jinja2/ext.py
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+++ b/.venv/lib/python3.12/site-packages/jinja2/ext.py
@@ -0,0 +1,870 @@
+"""Extension API for adding custom tags and behavior."""
+
+import pprint
+import re
+import typing as t
+
+from markupsafe import Markup
+
+from . import defaults
+from . import nodes
+from .environment import Environment
+from .exceptions import TemplateAssertionError
+from .exceptions import TemplateSyntaxError
+from .runtime import concat  # type: ignore
+from .runtime import Context
+from .runtime import Undefined
+from .utils import import_string
+from .utils import pass_context
+
+if t.TYPE_CHECKING:
+    import typing_extensions as te
+
+    from .lexer import Token
+    from .lexer import TokenStream
+    from .parser import Parser
+
+    class _TranslationsBasic(te.Protocol):
+        def gettext(self, message: str) -> str: ...
+
+        def ngettext(self, singular: str, plural: str, n: int) -> str:
+            pass
+
+    class _TranslationsContext(_TranslationsBasic):
+        def pgettext(self, context: str, message: str) -> str: ...
+
+        def npgettext(
+            self, context: str, singular: str, plural: str, n: int
+        ) -> str: ...
+
+    _SupportedTranslations = t.Union[_TranslationsBasic, _TranslationsContext]
+
+
+# I18N functions available in Jinja templates. If the I18N library
+# provides ugettext, it will be assigned to gettext.
+GETTEXT_FUNCTIONS: t.Tuple[str, ...] = (
+    "_",
+    "gettext",
+    "ngettext",
+    "pgettext",
+    "npgettext",
+)
+_ws_re = re.compile(r"\s*\n\s*")
+
+
+class Extension:
+    """Extensions can be used to add extra functionality to the Jinja template
+    system at the parser level.  Custom extensions are bound to an environment
+    but may not store environment specific data on `self`.  The reason for
+    this is that an extension can be bound to another environment (for
+    overlays) by creating a copy and reassigning the `environment` attribute.
+
+    As extensions are created by the environment they cannot accept any
+    arguments for configuration.  One may want to work around that by using
+    a factory function, but that is not possible as extensions are identified
+    by their import name.  The correct way to configure the extension is
+    storing the configuration values on the environment.  Because this way the
+    environment ends up acting as central configuration storage the
+    attributes may clash which is why extensions have to ensure that the names
+    they choose for configuration are not too generic.  ``prefix`` for example
+    is a terrible name, ``fragment_cache_prefix`` on the other hand is a good
+    name as includes the name of the extension (fragment cache).
+    """
+
+    identifier: t.ClassVar[str]
+
+    def __init_subclass__(cls) -> None:
+        cls.identifier = f"{cls.__module__}.{cls.__name__}"
+
+    #: if this extension parses this is the list of tags it's listening to.
+    tags: t.Set[str] = set()
+
+    #: the priority of that extension.  This is especially useful for
+    #: extensions that preprocess values.  A lower value means higher
+    #: priority.
+    #:
+    #: .. versionadded:: 2.4
+    priority = 100
+
+    def __init__(self, environment: Environment) -> None:
+        self.environment = environment
+
+    def bind(self, environment: Environment) -> "te.Self":
+        """Create a copy of this extension bound to another environment."""
+        rv = object.__new__(self.__class__)
+        rv.__dict__.update(self.__dict__)
+        rv.environment = environment
+        return rv
+
+    def preprocess(
+        self, source: str, name: t.Optional[str], filename: t.Optional[str] = None
+    ) -> str:
+        """This method is called before the actual lexing and can be used to
+        preprocess the source.  The `filename` is optional.  The return value
+        must be the preprocessed source.
+        """
+        return source
+
+    def filter_stream(
+        self, stream: "TokenStream"
+    ) -> t.Union["TokenStream", t.Iterable["Token"]]:
+        """It's passed a :class:`~jinja2.lexer.TokenStream` that can be used
+        to filter tokens returned.  This method has to return an iterable of
+        :class:`~jinja2.lexer.Token`\\s, but it doesn't have to return a
+        :class:`~jinja2.lexer.TokenStream`.
+        """
+        return stream
+
+    def parse(self, parser: "Parser") -> t.Union[nodes.Node, t.List[nodes.Node]]:
+        """If any of the :attr:`tags` matched this method is called with the
+        parser as first argument.  The token the parser stream is pointing at
+        is the name token that matched.  This method has to return one or a
+        list of multiple nodes.
+        """
+        raise NotImplementedError()
+
+    def attr(
+        self, name: str, lineno: t.Optional[int] = None
+    ) -> nodes.ExtensionAttribute:
+        """Return an attribute node for the current extension.  This is useful
+        to pass constants on extensions to generated template code.
+
+        ::
+
+            self.attr('_my_attribute', lineno=lineno)
+        """
+        return nodes.ExtensionAttribute(self.identifier, name, lineno=lineno)
+
+    def call_method(
+        self,
+        name: str,
+        args: t.Optional[t.List[nodes.Expr]] = None,
+        kwargs: t.Optional[t.List[nodes.Keyword]] = None,
+        dyn_args: t.Optional[nodes.Expr] = None,
+        dyn_kwargs: t.Optional[nodes.Expr] = None,
+        lineno: t.Optional[int] = None,
+    ) -> nodes.Call:
+        """Call a method of the extension.  This is a shortcut for
+        :meth:`attr` + :class:`jinja2.nodes.Call`.
+        """
+        if args is None:
+            args = []
+        if kwargs is None:
+            kwargs = []
+        return nodes.Call(
+            self.attr(name, lineno=lineno),
+            args,
+            kwargs,
+            dyn_args,
+            dyn_kwargs,
+            lineno=lineno,
+        )
+
+
+@pass_context
+def _gettext_alias(
+    __context: Context, *args: t.Any, **kwargs: t.Any
+) -> t.Union[t.Any, Undefined]:
+    return __context.call(__context.resolve("gettext"), *args, **kwargs)
+
+
+def _make_new_gettext(func: t.Callable[[str], str]) -> t.Callable[..., str]:
+    @pass_context
+    def gettext(__context: Context, __string: str, **variables: t.Any) -> str:
+        rv = __context.call(func, __string)
+        if __context.eval_ctx.autoescape:
+            rv = Markup(rv)
+        # Always treat as a format string, even if there are no
+        # variables. This makes translation strings more consistent
+        # and predictable. This requires escaping
+        return rv % variables  # type: ignore
+
+    return gettext
+
+
+def _make_new_ngettext(func: t.Callable[[str, str, int], str]) -> t.Callable[..., str]:
+    @pass_context
+    def ngettext(
+        __context: Context,
+        __singular: str,
+        __plural: str,
+        __num: int,
+        **variables: t.Any,
+    ) -> str:
+        variables.setdefault("num", __num)
+        rv = __context.call(func, __singular, __plural, __num)
+        if __context.eval_ctx.autoescape:
+            rv = Markup(rv)
+        # Always treat as a format string, see gettext comment above.
+        return rv % variables  # type: ignore
+
+    return ngettext
+
+
+def _make_new_pgettext(func: t.Callable[[str, str], str]) -> t.Callable[..., str]:
+    @pass_context
+    def pgettext(
+        __context: Context, __string_ctx: str, __string: str, **variables: t.Any
+    ) -> str:
+        variables.setdefault("context", __string_ctx)
+        rv = __context.call(func, __string_ctx, __string)
+
+        if __context.eval_ctx.autoescape:
+            rv = Markup(rv)
+
+        # Always treat as a format string, see gettext comment above.
+        return rv % variables  # type: ignore
+
+    return pgettext
+
+
+def _make_new_npgettext(
+    func: t.Callable[[str, str, str, int], str],
+) -> t.Callable[..., str]:
+    @pass_context
+    def npgettext(
+        __context: Context,
+        __string_ctx: str,
+        __singular: str,
+        __plural: str,
+        __num: int,
+        **variables: t.Any,
+    ) -> str:
+        variables.setdefault("context", __string_ctx)
+        variables.setdefault("num", __num)
+        rv = __context.call(func, __string_ctx, __singular, __plural, __num)
+
+        if __context.eval_ctx.autoescape:
+            rv = Markup(rv)
+
+        # Always treat as a format string, see gettext comment above.
+        return rv % variables  # type: ignore
+
+    return npgettext
+
+
+class InternationalizationExtension(Extension):
+    """This extension adds gettext support to Jinja."""
+
+    tags = {"trans"}
+
+    # TODO: the i18n extension is currently reevaluating values in a few
+    # situations.  Take this example:
+    #   {% trans count=something() %}{{ count }} foo{% pluralize
+    #     %}{{ count }} fooss{% endtrans %}
+    # something is called twice here.  One time for the gettext value and
+    # the other time for the n-parameter of the ngettext function.
+
+    def __init__(self, environment: Environment) -> None:
+        super().__init__(environment)
+        environment.globals["_"] = _gettext_alias
+        environment.extend(
+            install_gettext_translations=self._install,
+            install_null_translations=self._install_null,
+            install_gettext_callables=self._install_callables,
+            uninstall_gettext_translations=self._uninstall,
+            extract_translations=self._extract,
+            newstyle_gettext=False,
+        )
+
+    def _install(
+        self, translations: "_SupportedTranslations", newstyle: t.Optional[bool] = None
+    ) -> None:
+        # ugettext and ungettext are preferred in case the I18N library
+        # is providing compatibility with older Python versions.
+        gettext = getattr(translations, "ugettext", None)
+        if gettext is None:
+            gettext = translations.gettext
+        ngettext = getattr(translations, "ungettext", None)
+        if ngettext is None:
+            ngettext = translations.ngettext
+
+        pgettext = getattr(translations, "pgettext", None)
+        npgettext = getattr(translations, "npgettext", None)
+        self._install_callables(
+            gettext, ngettext, newstyle=newstyle, pgettext=pgettext, npgettext=npgettext
+        )
+
+    def _install_null(self, newstyle: t.Optional[bool] = None) -> None:
+        import gettext
+
+        translations = gettext.NullTranslations()
+
+        if hasattr(translations, "pgettext"):
+            # Python < 3.8
+            pgettext = translations.pgettext
+        else:
+
+            def pgettext(c: str, s: str) -> str:  # type: ignore[misc]
+                return s
+
+        if hasattr(translations, "npgettext"):
+            npgettext = translations.npgettext
+        else:
+
+            def npgettext(c: str, s: str, p: str, n: int) -> str:  # type: ignore[misc]
+                return s if n == 1 else p
+
+        self._install_callables(
+            gettext=translations.gettext,
+            ngettext=translations.ngettext,
+            newstyle=newstyle,
+            pgettext=pgettext,
+            npgettext=npgettext,
+        )
+
+    def _install_callables(
+        self,
+        gettext: t.Callable[[str], str],
+        ngettext: t.Callable[[str, str, int], str],
+        newstyle: t.Optional[bool] = None,
+        pgettext: t.Optional[t.Callable[[str, str], str]] = None,
+        npgettext: t.Optional[t.Callable[[str, str, str, int], str]] = None,
+    ) -> None:
+        if newstyle is not None:
+            self.environment.newstyle_gettext = newstyle  # type: ignore
+        if self.environment.newstyle_gettext:  # type: ignore
+            gettext = _make_new_gettext(gettext)
+            ngettext = _make_new_ngettext(ngettext)
+
+            if pgettext is not None:
+                pgettext = _make_new_pgettext(pgettext)
+
+            if npgettext is not None:
+                npgettext = _make_new_npgettext(npgettext)
+
+        self.environment.globals.update(
+            gettext=gettext, ngettext=ngettext, pgettext=pgettext, npgettext=npgettext
+        )
+
+    def _uninstall(self, translations: "_SupportedTranslations") -> None:
+        for key in ("gettext", "ngettext", "pgettext", "npgettext"):
+            self.environment.globals.pop(key, None)
+
+    def _extract(
+        self,
+        source: t.Union[str, nodes.Template],
+        gettext_functions: t.Sequence[str] = GETTEXT_FUNCTIONS,
+    ) -> t.Iterator[
+        t.Tuple[int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]]]
+    ]:
+        if isinstance(source, str):
+            source = self.environment.parse(source)
+        return extract_from_ast(source, gettext_functions)
+
+    def parse(self, parser: "Parser") -> t.Union[nodes.Node, t.List[nodes.Node]]:
+        """Parse a translatable tag."""
+        lineno = next(parser.stream).lineno
+
+        context = None
+        context_token = parser.stream.next_if("string")
+
+        if context_token is not None:
+            context = context_token.value
+
+        # find all the variables referenced.  Additionally a variable can be
+        # defined in the body of the trans block too, but this is checked at
+        # a later state.
+        plural_expr: t.Optional[nodes.Expr] = None
+        plural_expr_assignment: t.Optional[nodes.Assign] = None
+        num_called_num = False
+        variables: t.Dict[str, nodes.Expr] = {}
+        trimmed = None
+        while parser.stream.current.type != "block_end":
+            if variables:
+                parser.stream.expect("comma")
+
+            # skip colon for python compatibility
+            if parser.stream.skip_if("colon"):
+                break
+
+            token = parser.stream.expect("name")
+            if token.value in variables:
+                parser.fail(
+                    f"translatable variable {token.value!r} defined twice.",
+                    token.lineno,
+                    exc=TemplateAssertionError,
+                )
+
+            # expressions
+            if parser.stream.current.type == "assign":
+                next(parser.stream)
+                variables[token.value] = var = parser.parse_expression()
+            elif trimmed is None and token.value in ("trimmed", "notrimmed"):
+                trimmed = token.value == "trimmed"
+                continue
+            else:
+                variables[token.value] = var = nodes.Name(token.value, "load")
+
+            if plural_expr is None:
+                if isinstance(var, nodes.Call):
+                    plural_expr = nodes.Name("_trans", "load")
+                    variables[token.value] = plural_expr
+                    plural_expr_assignment = nodes.Assign(
+                        nodes.Name("_trans", "store"), var
+                    )
+                else:
+                    plural_expr = var
+                num_called_num = token.value == "num"
+
+        parser.stream.expect("block_end")
+
+        plural = None
+        have_plural = False
+        referenced = set()
+
+        # now parse until endtrans or pluralize
+        singular_names, singular = self._parse_block(parser, True)
+        if singular_names:
+            referenced.update(singular_names)
+            if plural_expr is None:
+                plural_expr = nodes.Name(singular_names[0], "load")
+                num_called_num = singular_names[0] == "num"
+
+        # if we have a pluralize block, we parse that too
+        if parser.stream.current.test("name:pluralize"):
+            have_plural = True
+            next(parser.stream)
+            if parser.stream.current.type != "block_end":
+                token = parser.stream.expect("name")
+                if token.value not in variables:
+                    parser.fail(
+                        f"unknown variable {token.value!r} for pluralization",
+                        token.lineno,
+                        exc=TemplateAssertionError,
+                    )
+                plural_expr = variables[token.value]
+                num_called_num = token.value == "num"
+            parser.stream.expect("block_end")
+            plural_names, plural = self._parse_block(parser, False)
+            next(parser.stream)
+            referenced.update(plural_names)
+        else:
+            next(parser.stream)
+
+        # register free names as simple name expressions
+        for name in referenced:
+            if name not in variables:
+                variables[name] = nodes.Name(name, "load")
+
+        if not have_plural:
+            plural_expr = None
+        elif plural_expr is None:
+            parser.fail("pluralize without variables", lineno)
+
+        if trimmed is None:
+            trimmed = self.environment.policies["ext.i18n.trimmed"]
+        if trimmed:
+            singular = self._trim_whitespace(singular)
+            if plural:
+                plural = self._trim_whitespace(plural)
+
+        node = self._make_node(
+            singular,
+            plural,
+            context,
+            variables,
+            plural_expr,
+            bool(referenced),
+            num_called_num and have_plural,
+        )
+        node.set_lineno(lineno)
+        if plural_expr_assignment is not None:
+            return [plural_expr_assignment, node]
+        else:
+            return node
+
+    def _trim_whitespace(self, string: str, _ws_re: t.Pattern[str] = _ws_re) -> str:
+        return _ws_re.sub(" ", string.strip())
+
+    def _parse_block(
+        self, parser: "Parser", allow_pluralize: bool
+    ) -> t.Tuple[t.List[str], str]:
+        """Parse until the next block tag with a given name."""
+        referenced = []
+        buf = []
+
+        while True:
+            if parser.stream.current.type == "data":
+                buf.append(parser.stream.current.value.replace("%", "%%"))
+                next(parser.stream)
+            elif parser.stream.current.type == "variable_begin":
+                next(parser.stream)
+                name = parser.stream.expect("name").value
+                referenced.append(name)
+                buf.append(f"%({name})s")
+                parser.stream.expect("variable_end")
+            elif parser.stream.current.type == "block_begin":
+                next(parser.stream)
+                block_name = (
+                    parser.stream.current.value
+                    if parser.stream.current.type == "name"
+                    else None
+                )
+                if block_name == "endtrans":
+                    break
+                elif block_name == "pluralize":
+                    if allow_pluralize:
+                        break
+                    parser.fail(
+                        "a translatable section can have only one pluralize section"
+                    )
+                elif block_name == "trans":
+                    parser.fail(
+                        "trans blocks can't be nested; did you mean `endtrans`?"
+                    )
+                parser.fail(
+                    f"control structures in translatable sections are not allowed; "
+                    f"saw `{block_name}`"
+                )
+            elif parser.stream.eos:
+                parser.fail("unclosed translation block")
+            else:
+                raise RuntimeError("internal parser error")
+
+        return referenced, concat(buf)
+
+    def _make_node(
+        self,
+        singular: str,
+        plural: t.Optional[str],
+        context: t.Optional[str],
+        variables: t.Dict[str, nodes.Expr],
+        plural_expr: t.Optional[nodes.Expr],
+        vars_referenced: bool,
+        num_called_num: bool,
+    ) -> nodes.Output:
+        """Generates a useful node from the data provided."""
+        newstyle = self.environment.newstyle_gettext  # type: ignore
+        node: nodes.Expr
+
+        # no variables referenced?  no need to escape for old style
+        # gettext invocations only if there are vars.
+        if not vars_referenced and not newstyle:
+            singular = singular.replace("%%", "%")
+            if plural:
+                plural = plural.replace("%%", "%")
+
+        func_name = "gettext"
+        func_args: t.List[nodes.Expr] = [nodes.Const(singular)]
+
+        if context is not None:
+            func_args.insert(0, nodes.Const(context))
+            func_name = f"p{func_name}"
+
+        if plural_expr is not None:
+            func_name = f"n{func_name}"
+            func_args.extend((nodes.Const(plural), plural_expr))
+
+        node = nodes.Call(nodes.Name(func_name, "load"), func_args, [], None, None)
+
+        # in case newstyle gettext is used, the method is powerful
+        # enough to handle the variable expansion and autoescape
+        # handling itself
+        if newstyle:
+            for key, value in variables.items():
+                # the function adds that later anyways in case num was
+                # called num, so just skip it.
+                if num_called_num and key == "num":
+                    continue
+                node.kwargs.append(nodes.Keyword(key, value))
+
+        # otherwise do that here
+        else:
+            # mark the return value as safe if we are in an
+            # environment with autoescaping turned on
+            node = nodes.MarkSafeIfAutoescape(node)
+            if variables:
+                node = nodes.Mod(
+                    node,
+                    nodes.Dict(
+                        [
+                            nodes.Pair(nodes.Const(key), value)
+                            for key, value in variables.items()
+                        ]
+                    ),
+                )
+        return nodes.Output([node])
+
+
+class ExprStmtExtension(Extension):
+    """Adds a `do` tag to Jinja that works like the print statement just
+    that it doesn't print the return value.
+    """
+
+    tags = {"do"}
+
+    def parse(self, parser: "Parser") -> nodes.ExprStmt:
+        node = nodes.ExprStmt(lineno=next(parser.stream).lineno)
+        node.node = parser.parse_tuple()
+        return node
+
+
+class LoopControlExtension(Extension):
+    """Adds break and continue to the template engine."""
+
+    tags = {"break", "continue"}
+
+    def parse(self, parser: "Parser") -> t.Union[nodes.Break, nodes.Continue]:
+        token = next(parser.stream)
+        if token.value == "break":
+            return nodes.Break(lineno=token.lineno)
+        return nodes.Continue(lineno=token.lineno)
+
+
+class DebugExtension(Extension):
+    """A ``{% debug %}`` tag that dumps the available variables,
+    filters, and tests.
+
+    .. code-block:: html+jinja
+
+        <pre>{% debug %}</pre>
+
+    .. code-block:: text
+
+        {'context': {'cycler': <class 'jinja2.utils.Cycler'>,
+                     ...,
+                     'namespace': <class 'jinja2.utils.Namespace'>},
+         'filters': ['abs', 'attr', 'batch', 'capitalize', 'center', 'count', 'd',
+                     ..., 'urlencode', 'urlize', 'wordcount', 'wordwrap', 'xmlattr'],
+         'tests': ['!=', '<', '<=', '==', '>', '>=', 'callable', 'defined',
+                   ..., 'odd', 'sameas', 'sequence', 'string', 'undefined', 'upper']}
+
+    .. versionadded:: 2.11.0
+    """
+
+    tags = {"debug"}
+
+    def parse(self, parser: "Parser") -> nodes.Output:
+        lineno = parser.stream.expect("name:debug").lineno
+        context = nodes.ContextReference()
+        result = self.call_method("_render", [context], lineno=lineno)
+        return nodes.Output([result], lineno=lineno)
+
+    def _render(self, context: Context) -> str:
+        result = {
+            "context": context.get_all(),
+            "filters": sorted(self.environment.filters.keys()),
+            "tests": sorted(self.environment.tests.keys()),
+        }
+
+        # Set the depth since the intent is to show the top few names.
+        return pprint.pformat(result, depth=3, compact=True)
+
+
+def extract_from_ast(
+    ast: nodes.Template,
+    gettext_functions: t.Sequence[str] = GETTEXT_FUNCTIONS,
+    babel_style: bool = True,
+) -> t.Iterator[
+    t.Tuple[int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]]]
+]:
+    """Extract localizable strings from the given template node.  Per
+    default this function returns matches in babel style that means non string
+    parameters as well as keyword arguments are returned as `None`.  This
+    allows Babel to figure out what you really meant if you are using
+    gettext functions that allow keyword arguments for placeholder expansion.
+    If you don't want that behavior set the `babel_style` parameter to `False`
+    which causes only strings to be returned and parameters are always stored
+    in tuples.  As a consequence invalid gettext calls (calls without a single
+    string parameter or string parameters after non-string parameters) are
+    skipped.
+
+    This example explains the behavior:
+
+    >>> from jinja2 import Environment
+    >>> env = Environment()
+    >>> node = env.parse('{{ (_("foo"), _(), ngettext("foo", "bar", 42)) }}')
+    >>> list(extract_from_ast(node))
+    [(1, '_', 'foo'), (1, '_', ()), (1, 'ngettext', ('foo', 'bar', None))]
+    >>> list(extract_from_ast(node, babel_style=False))
+    [(1, '_', ('foo',)), (1, 'ngettext', ('foo', 'bar'))]
+
+    For every string found this function yields a ``(lineno, function,
+    message)`` tuple, where:
+
+    * ``lineno`` is the number of the line on which the string was found,
+    * ``function`` is the name of the ``gettext`` function used (if the
+      string was extracted from embedded Python code), and
+    *   ``message`` is the string, or a tuple of strings for functions
+         with multiple string arguments.
+
+    This extraction function operates on the AST and is because of that unable
+    to extract any comments.  For comment support you have to use the babel
+    extraction interface or extract comments yourself.
+    """
+    out: t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]]
+
+    for node in ast.find_all(nodes.Call):
+        if (
+            not isinstance(node.node, nodes.Name)
+            or node.node.name not in gettext_functions
+        ):
+            continue
+
+        strings: t.List[t.Optional[str]] = []
+
+        for arg in node.args:
+            if isinstance(arg, nodes.Const) and isinstance(arg.value, str):
+                strings.append(arg.value)
+            else:
+                strings.append(None)
+
+        for _ in node.kwargs:
+            strings.append(None)
+        if node.dyn_args is not None:
+            strings.append(None)
+        if node.dyn_kwargs is not None:
+            strings.append(None)
+
+        if not babel_style:
+            out = tuple(x for x in strings if x is not None)
+
+            if not out:
+                continue
+        else:
+            if len(strings) == 1:
+                out = strings[0]
+            else:
+                out = tuple(strings)
+
+        yield node.lineno, node.node.name, out
+
+
+class _CommentFinder:
+    """Helper class to find comments in a token stream.  Can only
+    find comments for gettext calls forwards.  Once the comment
+    from line 4 is found, a comment for line 1 will not return a
+    usable value.
+    """
+
+    def __init__(
+        self, tokens: t.Sequence[t.Tuple[int, str, str]], comment_tags: t.Sequence[str]
+    ) -> None:
+        self.tokens = tokens
+        self.comment_tags = comment_tags
+        self.offset = 0
+        self.last_lineno = 0
+
+    def find_backwards(self, offset: int) -> t.List[str]:
+        try:
+            for _, token_type, token_value in reversed(
+                self.tokens[self.offset : offset]
+            ):
+                if token_type in ("comment", "linecomment"):
+                    try:
+                        prefix, comment = token_value.split(None, 1)
+                    except ValueError:
+                        continue
+                    if prefix in self.comment_tags:
+                        return [comment.rstrip()]
+            return []
+        finally:
+            self.offset = offset
+
+    def find_comments(self, lineno: int) -> t.List[str]:
+        if not self.comment_tags or self.last_lineno > lineno:
+            return []
+        for idx, (token_lineno, _, _) in enumerate(self.tokens[self.offset :]):
+            if token_lineno > lineno:
+                return self.find_backwards(self.offset + idx)
+        return self.find_backwards(len(self.tokens))
+
+
+def babel_extract(
+    fileobj: t.BinaryIO,
+    keywords: t.Sequence[str],
+    comment_tags: t.Sequence[str],
+    options: t.Dict[str, t.Any],
+) -> t.Iterator[
+    t.Tuple[
+        int, str, t.Union[t.Optional[str], t.Tuple[t.Optional[str], ...]], t.List[str]
+    ]
+]:
+    """Babel extraction method for Jinja templates.
+
+    .. versionchanged:: 2.3
+       Basic support for translation comments was added.  If `comment_tags`
+       is now set to a list of keywords for extraction, the extractor will
+       try to find the best preceding comment that begins with one of the
+       keywords.  For best results, make sure to not have more than one
+       gettext call in one line of code and the matching comment in the
+       same line or the line before.
+
+    .. versionchanged:: 2.5.1
+       The `newstyle_gettext` flag can be set to `True` to enable newstyle
+       gettext calls.
+
+    .. versionchanged:: 2.7
+       A `silent` option can now be provided.  If set to `False` template
+       syntax errors are propagated instead of being ignored.
+
+    :param fileobj: the file-like object the messages should be extracted from
+    :param keywords: a list of keywords (i.e. function names) that should be
+                     recognized as translation functions
+    :param comment_tags: a list of translator tags to search for and include
+                         in the results.
+    :param options: a dictionary of additional options (optional)
+    :return: an iterator over ``(lineno, funcname, message, comments)`` tuples.
+             (comments will be empty currently)
+    """
+    extensions: t.Dict[t.Type[Extension], None] = {}
+
+    for extension_name in options.get("extensions", "").split(","):
+        extension_name = extension_name.strip()
+
+        if not extension_name:
+            continue
+
+        extensions[import_string(extension_name)] = None
+
+    if InternationalizationExtension not in extensions:
+        extensions[InternationalizationExtension] = None
+
+    def getbool(options: t.Mapping[str, str], key: str, default: bool = False) -> bool:
+        return options.get(key, str(default)).lower() in {"1", "on", "yes", "true"}
+
+    silent = getbool(options, "silent", True)
+    environment = Environment(
+        options.get("block_start_string", defaults.BLOCK_START_STRING),
+        options.get("block_end_string", defaults.BLOCK_END_STRING),
+        options.get("variable_start_string", defaults.VARIABLE_START_STRING),
+        options.get("variable_end_string", defaults.VARIABLE_END_STRING),
+        options.get("comment_start_string", defaults.COMMENT_START_STRING),
+        options.get("comment_end_string", defaults.COMMENT_END_STRING),
+        options.get("line_statement_prefix") or defaults.LINE_STATEMENT_PREFIX,
+        options.get("line_comment_prefix") or defaults.LINE_COMMENT_PREFIX,
+        getbool(options, "trim_blocks", defaults.TRIM_BLOCKS),
+        getbool(options, "lstrip_blocks", defaults.LSTRIP_BLOCKS),
+        defaults.NEWLINE_SEQUENCE,
+        getbool(options, "keep_trailing_newline", defaults.KEEP_TRAILING_NEWLINE),
+        tuple(extensions),
+        cache_size=0,
+        auto_reload=False,
+    )
+
+    if getbool(options, "trimmed"):
+        environment.policies["ext.i18n.trimmed"] = True
+    if getbool(options, "newstyle_gettext"):
+        environment.newstyle_gettext = True  # type: ignore
+
+    source = fileobj.read().decode(options.get("encoding", "utf-8"))
+    try:
+        node = environment.parse(source)
+        tokens = list(environment.lex(environment.preprocess(source)))
+    except TemplateSyntaxError:
+        if not silent:
+            raise
+        # skip templates with syntax errors
+        return
+
+    finder = _CommentFinder(tokens, comment_tags)
+    for lineno, func, message in extract_from_ast(node, keywords):
+        yield lineno, func, message, finder.find_comments(lineno)
+
+
+#: nicer import names
+i18n = InternationalizationExtension
+do = ExprStmtExtension
+loopcontrols = LoopControlExtension
+debug = DebugExtension