Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/lib2to3/pytree.pyi

@@ -0,0 +1,97 @@
+import sys
+from lib2to3.pgen2.grammar import Grammar
+from typing import Any, Callable, Dict, Iterator, List, Optional, Text, Tuple, TypeVar, Union
+
+_P = TypeVar("_P")
+_NL = Union[Node, Leaf]
+_Context = Tuple[Text, int, int]
+_Results = Dict[Text, _NL]
+_RawNode = Tuple[int, Text, _Context, Optional[List[_NL]]]
+_Convert = Callable[[Grammar, _RawNode], Any]
+
+HUGE: int
+
+def type_repr(type_num: int) -> Text: ...
+
+class Base:
+    type: int
+    parent: Optional[Node]
+    prefix: Text
+    children: List[_NL]
+    was_changed: bool
+    was_checked: bool
+    def __eq__(self, other: Any) -> bool: ...
+    def _eq(self: _P, other: _P) -> bool: ...
+    def clone(self: _P) -> _P: ...
+    def post_order(self) -> Iterator[_NL]: ...
+    def pre_order(self) -> Iterator[_NL]: ...
+    def replace(self, new: Union[_NL, List[_NL]]) -> None: ...
+    def get_lineno(self) -> int: ...
+    def changed(self) -> None: ...
+    def remove(self) -> Optional[int]: ...
+    @property
+    def next_sibling(self) -> Optional[_NL]: ...
+    @property
+    def prev_sibling(self) -> Optional[_NL]: ...
+    def leaves(self) -> Iterator[Leaf]: ...
+    def depth(self) -> int: ...
+    def get_suffix(self) -> Text: ...
+    if sys.version_info < (3,):
+        def get_prefix(self) -> Text: ...
+        def set_prefix(self, prefix: Text) -> None: ...
+
+class Node(Base):
+    fixers_applied: List[Any]
+    def __init__(
+        self,
+        type: int,
+        children: List[_NL],
+        context: Optional[Any] = ...,
+        prefix: Optional[Text] = ...,
+        fixers_applied: Optional[List[Any]] = ...,
+    ) -> None: ...
+    def set_child(self, i: int, child: _NL) -> None: ...
+    def insert_child(self, i: int, child: _NL) -> None: ...
+    def append_child(self, child: _NL) -> None: ...
+
+class Leaf(Base):
+    lineno: int
+    column: int
+    value: Text
+    fixers_applied: List[Any]
+    def __init__(
+        self,
+        type: int,
+        value: Text,
+        context: Optional[_Context] = ...,
+        prefix: Optional[Text] = ...,
+        fixers_applied: List[Any] = ...,
+    ) -> None: ...
+
+def convert(gr: Grammar, raw_node: _RawNode) -> _NL: ...
+
+class BasePattern:
+    type: int
+    content: Optional[Text]
+    name: Optional[Text]
+    def optimize(self) -> BasePattern: ...  # sic, subclasses are free to optimize themselves into different patterns
+    def match(self, node: _NL, results: Optional[_Results] = ...) -> bool: ...
+    def match_seq(self, nodes: List[_NL], results: Optional[_Results] = ...) -> bool: ...
+    def generate_matches(self, nodes: List[_NL]) -> Iterator[Tuple[int, _Results]]: ...
+
+class LeafPattern(BasePattern):
+    def __init__(self, type: Optional[int] = ..., content: Optional[Text] = ..., name: Optional[Text] = ...) -> None: ...
+
+class NodePattern(BasePattern):
+    wildcards: bool
+    def __init__(self, type: Optional[int] = ..., content: Optional[Text] = ..., name: Optional[Text] = ...) -> None: ...
+
+class WildcardPattern(BasePattern):
+    min: int
+    max: int
+    def __init__(self, content: Optional[Text] = ..., min: int = ..., max: int = ..., name: Optional[Text] = ...) -> None: ...
+
+class NegatedPattern(BasePattern):
+    def __init__(self, content: Optional[Text] = ...) -> None: ...
+
+def generate_matches(patterns: List[BasePattern], nodes: List[_NL]) -> Iterator[Tuple[int, _Results]]: ...