bpo-42128: Structural Pattern Matching (PEP 634) (GH-22917)

Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Talin <viridia@gmail.com>
Co-authored-by: Pablo Galindo <pablogsal@gmail.com>

Doc/library/dis.rst

@@ -752,6 +752,49 @@ iterations of the loop.
    .. versionadded:: 3.2
 
 
+.. opcode:: COPY_DICT_WITHOUT_KEYS
+
+   TOS is a tuple of mapping keys, and TOS1 is the match subject.  Replace TOS
+   with a :class:`dict` formed from the items of TOS1, but without any of the
+   keys in TOS.
+
+   .. versionadded:: 3.10
+
+
+.. opcode:: GET_LEN
+
+   Push ``len(TOS)`` onto the stack.
+
+   .. versionadded:: 3.10
+
+
+.. opcode:: MATCH_MAPPING
+
+   If TOS is an instance of :class:`collections.abc.Mapping`, push ``True`` onto
+   the stack.  Otherwise, push ``False``.
+
+   .. versionadded:: 3.10
+
+
+.. opcode:: MATCH_SEQUENCE
+
+   If TOS is an instance of :class:`collections.abc.Sequence` and is *not* an
+   instance of :class:`str`/:class:`bytes`/:class:`bytearray`, push ``True``
+   onto the stack.  Otherwise, push ``False``.
+
+   .. versionadded:: 3.10
+
+
+.. opcode:: MATCH_KEYS
+
+   TOS is a tuple of mapping keys, and TOS1 is the match subject.  If TOS1
+   contains all of the keys in TOS, push a :class:`tuple` containing the
+   corresponding values, followed by ``True``. Otherwise, push ``None``,
+   followed by ``False``.
+
+   .. versionadded:: 3.10
+
+
 All of the following opcodes use their arguments.
 
 .. opcode:: STORE_NAME (namei)
@@ -1192,6 +1235,19 @@ All of the following opcodes use their arguments.
    .. versionadded:: 3.6
 
 
+.. opcode:: MATCH_CLASS (count)
+
+   TOS is a tuple of keyword attribute names, TOS1 is the class being matched
+   against, and TOS2 is the match subject.  *count* is the number of positional
+   sub-patterns.
+
+   Pop TOS.  If TOS2 is an instance of TOS1 and has the positional and keyword
+   attributes required by *count* and TOS, set TOS to ``True`` and TOS1 to a
+   tuple of extracted attributes.  Otherwise, set TOS to ``False``.
+
+   .. versionadded:: 3.10
+
+
 .. opcode:: HAVE_ARGUMENT
 
    This is not really an opcode.  It identifies the dividing line between

Doc/tools/susp-ignored.csv

@@ -365,3 +365,4 @@ whatsnew/changelog,,::,default::DeprecationWarning
 library/importlib.metadata,,:main,"EntryPoint(name='wheel', value='wheel.cli:main', group='console_scripts')"
 library/importlib.metadata,,`,loading the metadata for packages for the indicated ``context``.
 library/re,,`,"`"
+library/dis,,:TOS1,TOS[x:TOS1 - 1 - y]

Grammar/python.gram

@@ -85,6 +85,7 @@ compound_stmt[stmt_ty]:
     | &('for' | ASYNC) for_stmt
     | &'try' try_stmt
     | &'while' while_stmt
+    | match_stmt
 
 # NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield'
 assignment[stmt_ty]:
@@ -207,6 +208,114 @@ except_block[excepthandler_ty]:
     | invalid_except_block
 finally_block[asdl_stmt_seq*]: 'finally' ':' a=block { a }
 
+match_stmt[stmt_ty]:
+    | "match" subject=subject_expr ':' NEWLINE INDENT cases[asdl_match_case_seq*]=case_block+ DEDENT {
+        CHECK_VERSION(stmt_ty, 10, "Pattern matching is", _Py_Match(subject, cases, EXTRA)) }
+subject_expr[expr_ty]:
+    | value=star_named_expression ',' values=star_named_expressions? {
+        _Py_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, value, values)), Load, EXTRA) }
+    | named_expression
+case_block[match_case_ty]:
+    | "case" pattern=patterns guard=guard? ':' body=block {
+        _Py_match_case(pattern, guard, body, p->arena) }
+guard[expr_ty]: 'if' guard=named_expression { guard }
+
+patterns[expr_ty]:
+    | values[asdl_expr_seq*]=open_sequence_pattern {
+        _Py_Tuple(values, Load, EXTRA) }
+    | pattern
+pattern[expr_ty]:
+    | as_pattern
+    | or_pattern
+as_pattern[expr_ty]:
+    | pattern=or_pattern 'as' target=capture_pattern {
+        _Py_MatchAs(pattern, target->v.Name.id, EXTRA) }
+or_pattern[expr_ty]:
+    | patterns[asdl_expr_seq*]='|'.closed_pattern+ {
+        asdl_seq_LEN(patterns) == 1 ? asdl_seq_GET(patterns, 0) : _Py_MatchOr(patterns, EXTRA) }
+closed_pattern[expr_ty]:
+    | literal_pattern
+    | capture_pattern
+    | wildcard_pattern
+    | value_pattern
+    | group_pattern
+    | sequence_pattern
+    | mapping_pattern
+    | class_pattern
+
+literal_pattern[expr_ty]:
+    | signed_number !('+' | '-')
+    | real=signed_number '+' imag=NUMBER { _Py_BinOp(real, Add, imag, EXTRA) }
+    | real=signed_number '-' imag=NUMBER  { _Py_BinOp(real, Sub, imag, EXTRA) }
+    | strings
+    | 'None' { _Py_Constant(Py_None, NULL, EXTRA) }
+    | 'True' { _Py_Constant(Py_True, NULL, EXTRA) }
+    | 'False' { _Py_Constant(Py_False, NULL, EXTRA) }
+signed_number[expr_ty]:
+    | NUMBER
+    | '-' number=NUMBER { _Py_UnaryOp(USub, number, EXTRA) }
+
+capture_pattern[expr_ty]:
+    | !"_" name=NAME !('.' | '(' | '=') {
+        _PyPegen_set_expr_context(p, name, Store) }
+
+wildcard_pattern[expr_ty]:
+    | "_" { _Py_Name(CHECK(PyObject*, _PyPegen_new_identifier(p, "_")), Store, EXTRA) }
+
+value_pattern[expr_ty]:
+    | attr=attr !('.' | '(' | '=') { attr }
+attr[expr_ty]:
+    | value=name_or_attr '.' attr=NAME {
+        _Py_Attribute(value, attr->v.Name.id, Load, EXTRA) }
+name_or_attr[expr_ty]:
+    | attr
+    | NAME
+
+group_pattern[expr_ty]:
+    | '(' pattern=pattern ')' { pattern }
+
+sequence_pattern[expr_ty]:
+    | '[' values=maybe_sequence_pattern? ']' { _Py_List(values, Load, EXTRA) }
+    | '(' values=open_sequence_pattern? ')' { _Py_Tuple(values, Load, EXTRA) }
+open_sequence_pattern[asdl_seq*]:
+    | value=maybe_star_pattern ',' values=maybe_sequence_pattern? {
+        _PyPegen_seq_insert_in_front(p, value, values) }
+maybe_sequence_pattern[asdl_seq*]:
+    | values=','.maybe_star_pattern+ ','? { values }
+maybe_star_pattern[expr_ty]:
+    | star_pattern
+    | pattern
+star_pattern[expr_ty]:
+    | '*' value=(capture_pattern | wildcard_pattern) {
+        _Py_Starred(value, Store, EXTRA) }
+
+mapping_pattern[expr_ty]:
+    | '{' items=items_pattern? '}' {
+        _Py_Dict(CHECK(asdl_expr_seq*, _PyPegen_get_keys(p, items)), CHECK(asdl_expr_seq*, _PyPegen_get_values(p, items)), EXTRA) }
+items_pattern[asdl_seq*]:
+    | items=','.key_value_pattern+ ','? { items }
+key_value_pattern[KeyValuePair*]:
+    | key=(literal_pattern | value_pattern) ':' value=pattern {
+        _PyPegen_key_value_pair(p, key, value) }
+    | double_star_pattern
+double_star_pattern[KeyValuePair*]:
+    | '**' value=capture_pattern { _PyPegen_key_value_pair(p, NULL, value) }
+
+class_pattern[expr_ty]:
+    | func=name_or_attr '(' ')' { _Py_Call(func, NULL, NULL, EXTRA) }
+    | func=name_or_attr '(' args=positional_patterns ','? ')' {
+        _Py_Call(func, args, NULL, EXTRA) }
+    | func=name_or_attr '(' keywords=keyword_patterns ','? ')' {
+        _Py_Call(func, NULL, keywords, EXTRA) }
+    | func=name_or_attr '(' args=positional_patterns ',' keywords=keyword_patterns ','? ')' {
+        _Py_Call(func, args, keywords, EXTRA) }
+positional_patterns[asdl_expr_seq*]:
+    | args[asdl_expr_seq*]=','.pattern+ { args }
+keyword_patterns[asdl_keyword_seq*]:
+    | keywords[asdl_keyword_seq*]=','.keyword_pattern+ { keywords }
+keyword_pattern[keyword_ty]:
+    | arg=NAME '=' value=pattern { _Py_keyword(arg->v.Name.id, value, EXTRA) }
+
 return_stmt[stmt_ty]:
     | 'return' a=[star_expressions] { _Py_Return(a, EXTRA) }
 
@@ -676,7 +785,7 @@ invalid_assignment:
         RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
     | (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") }
     | a=star_expressions augassign (yield_expr | star_expressions) {
-        RAISE_SYNTAX_ERROR_KNOWN_LOCATION( 
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
             a,
             "'%s' is an illegal expression for augmented assignment",
             _PyPegen_get_expr_name(a)

Include/Python-ast.h

@@ -44,6 +44,8 @@ typedef struct _alias *alias_ty;
 
 typedef struct _withitem *withitem_ty;
 
+typedef struct _match_case *match_case_ty;
+
 typedef struct _type_ignore *type_ignore_ty;
 
 
@@ -119,6 +121,14 @@ typedef struct {
 
 asdl_withitem_seq *_Py_asdl_withitem_seq_new(Py_ssize_t size, PyArena *arena);
 
+typedef struct {
+    _ASDL_SEQ_HEAD
+    match_case_ty typed_elements[1];
+} asdl_match_case_seq;
+
+asdl_match_case_seq *_Py_asdl_match_case_seq_new(Py_ssize_t size, PyArena
+                                                 *arena);
+
 typedef struct {
     _ASDL_SEQ_HEAD
     type_ignore_ty typed_elements[1];
@@ -158,10 +168,10 @@ enum _stmt_kind {FunctionDef_kind=1, AsyncFunctionDef_kind=2, ClassDef_kind=3,
                   Return_kind=4, Delete_kind=5, Assign_kind=6,
                   AugAssign_kind=7, AnnAssign_kind=8, For_kind=9,
                   AsyncFor_kind=10, While_kind=11, If_kind=12, With_kind=13,
-                  AsyncWith_kind=14, Raise_kind=15, Try_kind=16,
+                  AsyncWith_kind=14, Match_kind=15, Raise_kind=16, Try_kind=17,
-                  Assert_kind=17, Import_kind=18, ImportFrom_kind=19,
+                  Assert_kind=18, Import_kind=19, ImportFrom_kind=20,
-                  Global_kind=20, Nonlocal_kind=21, Expr_kind=22, Pass_kind=23,
+                  Global_kind=21, Nonlocal_kind=22, Expr_kind=23, Pass_kind=24,
-                  Break_kind=24, Continue_kind=25};
+                  Break_kind=25, Continue_kind=26};
 struct _stmt {
     enum _stmt_kind kind;
     union {
@@ -258,6 +268,11 @@ struct _stmt {
             string type_comment;
         } AsyncWith;
 
+        struct {
+            expr_ty subject;
+            asdl_match_case_seq *cases;
+        } Match;
+
         struct {
             expr_ty exc;
             expr_ty cause;
@@ -311,7 +326,8 @@ enum _expr_kind {BoolOp_kind=1, NamedExpr_kind=2, BinOp_kind=3, UnaryOp_kind=4,
                   YieldFrom_kind=15, Compare_kind=16, Call_kind=17,
                   FormattedValue_kind=18, JoinedStr_kind=19, Constant_kind=20,
                   Attribute_kind=21, Subscript_kind=22, Starred_kind=23,
-                  Name_kind=24, List_kind=25, Tuple_kind=26, Slice_kind=27};
+                  Name_kind=24, List_kind=25, Tuple_kind=26, Slice_kind=27,
+                  MatchAs_kind=28, MatchOr_kind=29};
 struct _expr {
     enum _expr_kind kind;
     union {
@@ -454,6 +470,15 @@ struct _expr {
             expr_ty step;
         } Slice;
 
+        struct {
+            expr_ty pattern;
+            identifier name;
+        } MatchAs;
+
+        struct {
+            asdl_expr_seq *patterns;
+        } MatchOr;
+
     } v;
     int lineno;
     int col_offset;
@@ -524,6 +549,12 @@ struct _withitem {
     expr_ty optional_vars;
 };
 
+struct _match_case {
+    expr_ty pattern;
+    expr_ty guard;
+    asdl_stmt_seq *body;
+};
+
 enum _type_ignore_kind {TypeIgnore_kind=1};
 struct _type_ignore {
     enum _type_ignore_kind kind;
@@ -607,6 +638,10 @@ stmt_ty _Py_With(asdl_withitem_seq * items, asdl_stmt_seq * body, string
 stmt_ty _Py_AsyncWith(asdl_withitem_seq * items, asdl_stmt_seq * body, string
                       type_comment, int lineno, int col_offset, int end_lineno,
                       int end_col_offset, PyArena *arena);
+#define Match(a0, a1, a2, a3, a4, a5, a6) _Py_Match(a0, a1, a2, a3, a4, a5, a6)
+stmt_ty _Py_Match(expr_ty subject, asdl_match_case_seq * cases, int lineno, int
+                  col_offset, int end_lineno, int end_col_offset, PyArena
+                  *arena);
 #define Raise(a0, a1, a2, a3, a4, a5, a6) _Py_Raise(a0, a1, a2, a3, a4, a5, a6)
 stmt_ty _Py_Raise(expr_ty exc, expr_ty cause, int lineno, int col_offset, int
                   end_lineno, int end_col_offset, PyArena *arena);
@@ -743,6 +778,13 @@ expr_ty _Py_Tuple(asdl_expr_seq * elts, expr_context_ty ctx, int lineno, int
 expr_ty _Py_Slice(expr_ty lower, expr_ty upper, expr_ty step, int lineno, int
                   col_offset, int end_lineno, int end_col_offset, PyArena
                   *arena);
+#define MatchAs(a0, a1, a2, a3, a4, a5, a6) _Py_MatchAs(a0, a1, a2, a3, a4, a5, a6)
+expr_ty _Py_MatchAs(expr_ty pattern, identifier name, int lineno, int
+                    col_offset, int end_lineno, int end_col_offset, PyArena
+                    *arena);
+#define MatchOr(a0, a1, a2, a3, a4, a5) _Py_MatchOr(a0, a1, a2, a3, a4, a5)
+expr_ty _Py_MatchOr(asdl_expr_seq * patterns, int lineno, int col_offset, int
+                    end_lineno, int end_col_offset, PyArena *arena);
 #define comprehension(a0, a1, a2, a3, a4) _Py_comprehension(a0, a1, a2, a3, a4)
 comprehension_ty _Py_comprehension(expr_ty target, expr_ty iter, asdl_expr_seq
                                    * ifs, int is_async, PyArena *arena);
@@ -769,6 +811,9 @@ alias_ty _Py_alias(identifier name, identifier asname, PyArena *arena);
 #define withitem(a0, a1, a2) _Py_withitem(a0, a1, a2)
 withitem_ty _Py_withitem(expr_ty context_expr, expr_ty optional_vars, PyArena
                          *arena);
+#define match_case(a0, a1, a2, a3) _Py_match_case(a0, a1, a2, a3)
+match_case_ty _Py_match_case(expr_ty pattern, expr_ty guard, asdl_stmt_seq *
+                             body, PyArena *arena);
 #define TypeIgnore(a0, a1, a2) _Py_TypeIgnore(a0, a1, a2)
 type_ignore_ty _Py_TypeIgnore(int lineno, string tag, PyArena *arena);
 

Include/internal/pycore_ast.h

@@ -91,6 +91,9 @@ struct ast_state {
     PyObject *Lt_type;
     PyObject *MatMult_singleton;
     PyObject *MatMult_type;
+    PyObject *MatchAs_type;
+    PyObject *MatchOr_type;
+    PyObject *Match_type;
     PyObject *Mod_singleton;
     PyObject *Mod_type;
     PyObject *Module_type;
@@ -137,6 +140,7 @@ struct ast_state {
     PyObject *Yield_type;
     PyObject *__dict__;
     PyObject *__doc__;
+    PyObject *__match_args__;
     PyObject *__module__;
     PyObject *_attributes;
     PyObject *_fields;
@@ -153,6 +157,7 @@ struct ast_state {
     PyObject *bases;
     PyObject *body;
     PyObject *boolop_type;
+    PyObject *cases;
     PyObject *cause;
     PyObject *cmpop_type;
     PyObject *col_offset;
@@ -175,6 +180,7 @@ struct ast_state {
     PyObject *format_spec;
     PyObject *func;
     PyObject *generators;
+    PyObject *guard;
     PyObject *handlers;
     PyObject *id;
     PyObject *ifs;
@@ -193,6 +199,7 @@ struct ast_state {
     PyObject *level;
     PyObject *lineno;
     PyObject *lower;
+    PyObject *match_case_type;
     PyObject *mod_type;
     PyObject *module;
     PyObject *msg;
@@ -204,6 +211,8 @@ struct ast_state {
     PyObject *ops;
     PyObject *optional_vars;
     PyObject *orelse;
+    PyObject *pattern;
+    PyObject *patterns;
     PyObject *posonlyargs;
     PyObject *returns;
     PyObject *right;
@@ -211,6 +220,7 @@ struct ast_state {
     PyObject *slice;
     PyObject *step;
     PyObject *stmt_type;
+    PyObject *subject;
     PyObject *tag;
     PyObject *target;
     PyObject *targets;

Include/internal/pycore_interp.h

@@ -253,6 +253,10 @@ struct _is {
     // importlib module
     PyObject *importlib;
 
+    // Kept handy for pattern matching:
+    PyObject *map_abc;  // _collections_abc.Mapping
+    PyObject *seq_abc;  // _collections_abc.Sequence
+
     /* Used in Modules/_threadmodule.c. */
     long num_threads;
     /* Support for runtime thread stack size tuning.
@@ -347,4 +351,3 @@ PyAPI_FUNC(void) _PyInterpreterState_IDDecref(struct _is *);
 }
 #endif
 #endif /* !Py_INTERNAL_INTERP_H */
-

Include/object.h

@@ -359,6 +359,11 @@ given type object has a specified feature.
 #define Py_TPFLAGS_HAVE_AM_SEND (1UL << 21)
 #endif
 
+// This undocumented flag gives certain built-ins their unique pattern-matching
+// behavior, which allows a single positional subpattern to match against the
+// subject itself (rather than a mapped attribute on it):
+#define _Py_TPFLAGS_MATCH_SELF (1UL << 22)
+
 /* These flags are used to determine if a type is a subclass. */
 #define Py_TPFLAGS_LONG_SUBCLASS        (1UL << 24)
 #define Py_TPFLAGS_LIST_SUBCLASS        (1UL << 25)

Include/opcode.h

@@ -30,6 +30,11 @@ extern "C" {
 #define BINARY_TRUE_DIVIDE       27
 #define INPLACE_FLOOR_DIVIDE     28
 #define INPLACE_TRUE_DIVIDE      29
+#define GET_LEN                  30
+#define MATCH_MAPPING            31
+#define MATCH_SEQUENCE           32
+#define MATCH_KEYS               33
+#define COPY_DICT_WITHOUT_KEYS   34
 #define WITH_EXCEPT_START        49
 #define GET_AITER                50
 #define GET_ANEXT                51
@@ -117,6 +122,7 @@ extern "C" {
 #define SET_ADD                 146
 #define MAP_ADD                 147
 #define LOAD_CLASSDEREF         148
+#define MATCH_CLASS             152
 #define SETUP_ASYNC_WITH        154
 #define FORMAT_VALUE            155
 #define BUILD_CONST_KEY_MAP     156

Include/symtable.h

@@ -33,6 +33,7 @@ struct symtable {
                                        the symbol table */
     int recursion_depth;            /* current recursion depth */
     int recursion_limit;            /* recursion limit */
+    int in_pattern;                 /* whether we are currently in a pattern */
 };
 
 typedef struct _symtable_entry {

Lib/ast.py

@@ -1478,6 +1478,13 @@ class _Unparser(NodeVisitor):
             self.write(":")
             self.traverse(node.step)
 
+    def visit_Match(self, node):
+        self.fill("match ")
+        self.traverse(node.subject)
+        with self.block():
+            for case in node.cases:
+                self.traverse(case)
+
     def visit_arg(self, node):
         self.write(node.arg)
         if node.annotation:
@@ -1562,6 +1569,26 @@ class _Unparser(NodeVisitor):
             self.write(" as ")
             self.traverse(node.optional_vars)
 
+    def visit_match_case(self, node):
+        self.fill("case ")
+        self.traverse(node.pattern)
+        if node.guard:
+            self.write(" if ")
+            self.traverse(node.guard)
+        with self.block():
+            self.traverse(node.body)
+
+    def visit_MatchAs(self, node):
+        with self.require_parens(_Precedence.TEST, node):
+            self.set_precedence(_Precedence.BOR, node.pattern)
+            self.traverse(node.pattern)
+            self.write(f" as {node.name}")
+
+    def visit_MatchOr(self, node):
+        with self.require_parens(_Precedence.BOR, node):
+            self.set_precedence(_Precedence.BOR.next(), *node.patterns)
+            self.interleave(lambda: self.write(" | "), self.traverse, node.patterns)
+
 def unparse(ast_obj):
     unparser = _Unparser()
     return unparser.visit(ast_obj)

Lib/collections/__init__.py

@@ -472,6 +472,7 @@ def namedtuple(typename, field_names, *, rename=False, defaults=None, module=Non
         '__repr__': __repr__,
         '_asdict': _asdict,
         '__getnewargs__': __getnewargs__,
+        '__match_args__': field_names,
     }
     for index, name in enumerate(field_names):
         doc = _sys.intern(f'Alias for field number {index}')

Lib/dataclasses.py

@@ -152,6 +152,15 @@ __all__ = ['dataclass',
 #
 # See _hash_action (below) for a coded version of this table.
 
+# __match_args__
+#
+# |  no   |  yes  |  <--- class has __match_args__ in __dict__?
+# +=======+=======+
+# | add   |       |  <- the default
+# +=======+=======+
+# __match_args__ is always added unless the class already defines it. It is a
+# tuple of __init__ parameter names; non-init fields must be matched by keyword.
+
 
 # Raised when an attempt is made to modify a frozen class.
 class FrozenInstanceError(AttributeError): pass
@@ -1007,6 +1016,9 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen):
         cls.__doc__ = (cls.__name__ +
                        str(inspect.signature(cls)).replace(' -> NoneType', ''))
 
+    if '__match_args__' not in cls.__dict__:
+        cls.__match_args__ = tuple(f.name for f in flds if f.init)
+
     abc.update_abstractmethods(cls)
 
     return cls

Lib/importlib/_bootstrap_external.py

@@ -313,6 +313,7 @@ _code_type = type(_write_atomic.__code__)
 #     Python 3.10a1 3431 (New line number table format -- PEP 626)
 #     Python 3.10a2 3432 (Function annotation for MAKE_FUNCTION is changed from dict to tuple bpo-42202)
 #     Python 3.10a2 3433 (RERAISE restores f_lasti if oparg != 0)
+#     Python 3.10a6 3434 (PEP 634: Structural Pattern Matching)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -322,7 +323,7 @@ _code_type = type(_write_atomic.__code__)
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3433).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3434).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'

Lib/keyword.py

@@ -54,7 +54,9 @@ kwlist = [
 ]
 
 softkwlist = [
-
+    '_',
+    'case',
+    'match'
 ]
 
 iskeyword = frozenset(kwlist).__contains__

Lib/opcode.py

@@ -67,7 +67,6 @@ def_op('UNARY_NEGATIVE', 11)
 def_op('UNARY_NOT', 12)
 
 def_op('UNARY_INVERT', 15)
-
 def_op('BINARY_MATRIX_MULTIPLY', 16)
 def_op('INPLACE_MATRIX_MULTIPLY', 17)
 
@@ -82,6 +81,11 @@ def_op('BINARY_FLOOR_DIVIDE', 26)
 def_op('BINARY_TRUE_DIVIDE', 27)
 def_op('INPLACE_FLOOR_DIVIDE', 28)
 def_op('INPLACE_TRUE_DIVIDE', 29)
+def_op('GET_LEN', 30)
+def_op('MATCH_MAPPING', 31)
+def_op('MATCH_SEQUENCE', 32)
+def_op('MATCH_KEYS', 33)
+def_op('COPY_DICT_WITHOUT_KEYS', 34)
 
 def_op('WITH_EXCEPT_START', 49)
 def_op('GET_AITER', 50)
@@ -104,7 +108,6 @@ def_op('BINARY_OR', 66)
 def_op('INPLACE_POWER', 67)
 def_op('GET_ITER', 68)
 def_op('GET_YIELD_FROM_ITER', 69)
-
 def_op('PRINT_EXPR', 70)
 def_op('LOAD_BUILD_CLASS', 71)
 def_op('YIELD_FROM', 72)
@@ -136,6 +139,7 @@ name_op('STORE_ATTR', 95)       # Index in name list
 name_op('DELETE_ATTR', 96)      # ""
 name_op('STORE_GLOBAL', 97)     # ""
 name_op('DELETE_GLOBAL', 98)    # ""
+
 def_op('LOAD_CONST', 100)       # Index in const list
 hasconst.append(100)
 name_op('LOAD_NAME', 101)       # Index in name list
@@ -148,16 +152,13 @@ def_op('COMPARE_OP', 107)       # Comparison operator
 hascompare.append(107)
 name_op('IMPORT_NAME', 108)     # Index in name list
 name_op('IMPORT_FROM', 109)     # Index in name list
-
 jrel_op('JUMP_FORWARD', 110)    # Number of bytes to skip
 jabs_op('JUMP_IF_FALSE_OR_POP', 111) # Target byte offset from beginning of code
 jabs_op('JUMP_IF_TRUE_OR_POP', 112)  # ""
 jabs_op('JUMP_ABSOLUTE', 113)        # ""
 jabs_op('POP_JUMP_IF_FALSE', 114)    # ""
 jabs_op('POP_JUMP_IF_TRUE', 115)     # ""
-
 name_op('LOAD_GLOBAL', 116)     # Index in name list
-
 def_op('IS_OP', 117)
 def_op('CONTAINS_OP', 118)
 def_op('RERAISE', 119)
@@ -176,6 +177,7 @@ def_op('RAISE_VARARGS', 130)    # Number of raise arguments (1, 2, or 3)
 def_op('CALL_FUNCTION', 131)    # #args
 def_op('MAKE_FUNCTION', 132)    # Flags
 def_op('BUILD_SLICE', 133)      # Number of items
+
 def_op('LOAD_CLOSURE', 135)
 hasfree.append(135)
 def_op('LOAD_DEREF', 136)
@@ -187,28 +189,24 @@ hasfree.append(138)
 
 def_op('CALL_FUNCTION_KW', 141)  # #args + #kwargs
 def_op('CALL_FUNCTION_EX', 142)  # Flags
-
 jrel_op('SETUP_WITH', 143)
-
+def_op('EXTENDED_ARG', 144)
+EXTENDED_ARG = 144
 def_op('LIST_APPEND', 145)
 def_op('SET_ADD', 146)
 def_op('MAP_ADD', 147)
-
 def_op('LOAD_CLASSDEREF', 148)
 hasfree.append(148)
 
-def_op('EXTENDED_ARG', 144)
+def_op('MATCH_CLASS', 152)
-EXTENDED_ARG = 144
 
 jrel_op('SETUP_ASYNC_WITH', 154)
-
 def_op('FORMAT_VALUE', 155)
 def_op('BUILD_CONST_KEY_MAP', 156)
 def_op('BUILD_STRING', 157)
 
 name_op('LOAD_METHOD', 160)
 def_op('CALL_METHOD', 161)
-
 def_op('LIST_EXTEND', 162)
 def_op('SET_UPDATE', 163)
 def_op('DICT_MERGE', 164)

Lib/test/libregrtest/pgo.py

@@ -35,6 +35,7 @@ PGO_TESTS = [
     'test_memoryview',
     'test_operator',
     'test_ordered_dict',
+    'test_patma',
     'test_pickle',
     'test_pprint',
     'test_re',

Lib/test/test_ast.py

@@ -273,6 +273,7 @@ class AST_Tests(unittest.TestCase):
                     self._assertTrueorder(child, first_pos)
             elif value is not None:
                 self._assertTrueorder(value, parent_pos)
+        self.assertEqual(ast_node._fields, ast_node.__match_args__)
 
     def test_AST_objects(self):
         x = ast.AST()

Lib/test/test_collections.py

@@ -687,6 +687,10 @@ class TestNamedTuple(unittest.TestCase):
         self.assertEqual(new_func.__globals__['__builtins__'], {})
         self.assertEqual(new_func.__builtins__, {})
 
+    def test_match_args(self):
+        Point = namedtuple('Point', 'x y')
+        self.assertEqual(Point.__match_args__, ('x', 'y'))
+
 
 ################################################################################
 ### Abstract Base Classes

Lib/test/test_dataclasses.py

@@ -3375,5 +3375,21 @@ class TestAbstract(unittest.TestCase):
         self.assertRaisesRegex(TypeError, msg, Date)
 
 
+class TestMatchArgs(unittest.TestCase):
+    def test_match_args(self):
+        @dataclass
+        class C:
+            a: int
+        self.assertEqual(C(42).__match_args__, ('a',))
+
+    def test_explicit_match_args(self):
+        ma = []
+        @dataclass
+        class C:
+            a: int
+            __match_args__ = ma
+        self.assertIs(C(42).__match_args__, ma)
+
+
 if __name__ == '__main__':
     unittest.main()

Misc/NEWS.d/next/Core and Builtins/2020-10-23-08-54-04.bpo-42128.SWmVEm.rst

@@ -0,0 +1 @@
+Implement :pep:`634` (structural pattern matching). Patch by Brandt Bucher.

Objects/bytearrayobject.c

@@ -2337,7 +2337,8 @@ PyTypeObject PyByteArray_Type = {
     PyObject_GenericGetAttr,            /* tp_getattro */
     0,                                  /* tp_setattro */
     &bytearray_as_buffer,               /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,       /* tp_flags */
     bytearray_doc,                      /* tp_doc */
     0,                                  /* tp_traverse */
     0,                                  /* tp_clear */

Objects/bytesobject.c

@@ -2912,7 +2912,8 @@ PyTypeObject PyBytes_Type = {
     0,                                          /* tp_setattro */
     &bytes_as_buffer,                           /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-        Py_TPFLAGS_BYTES_SUBCLASS,              /* tp_flags */
+        Py_TPFLAGS_BYTES_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     bytes_doc,                                  /* tp_doc */
     0,                                          /* tp_traverse */
     0,                                          /* tp_clear */

Objects/dictobject.c

@@ -3549,7 +3549,8 @@ PyTypeObject PyDict_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS,         /* tp_flags */
+        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     dictionary_doc,                             /* tp_doc */
     dict_traverse,                              /* tp_traverse */
     dict_tp_clear,                              /* tp_clear */

Objects/floatobject.c

@@ -1945,7 +1945,8 @@ PyTypeObject PyFloat_Type = {
     PyObject_GenericGetAttr,                    /* tp_getattro */
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,   /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     float_new__doc__,                           /* tp_doc */
     0,                                          /* tp_traverse */
     0,                                          /* tp_clear */

Objects/listobject.c

@@ -3052,7 +3052,8 @@ PyTypeObject PyList_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LIST_SUBCLASS, /* tp_flags */
+        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LIST_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     list___init____doc__,                       /* tp_doc */
     (traverseproc)list_traverse,                /* tp_traverse */
     (inquiry)_list_clear,                       /* tp_clear */

Objects/longobject.c

@@ -5639,7 +5639,8 @@ PyTypeObject PyLong_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-        Py_TPFLAGS_LONG_SUBCLASS,               /* tp_flags */
+        Py_TPFLAGS_LONG_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     long_doc,                                   /* tp_doc */
     0,                                          /* tp_traverse */
     0,                                          /* tp_clear */

Objects/setobject.c

@@ -2093,7 +2093,8 @@ PyTypeObject PySet_Type = {
     0,                                  /* tp_setattro */
     0,                                  /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE,            /* tp_flags */
+        Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,       /* tp_flags */
     set_doc,                            /* tp_doc */
     (traverseproc)set_traverse,         /* tp_traverse */
     (inquiry)set_clear_internal,        /* tp_clear */
@@ -2193,7 +2194,8 @@ PyTypeObject PyFrozenSet_Type = {
     0,                                  /* tp_setattro */
     0,                                  /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE,            /* tp_flags */
+        Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,       /* tp_flags */
     frozenset_doc,                      /* tp_doc */
     (traverseproc)set_traverse,         /* tp_traverse */
     (inquiry)set_clear_internal,        /* tp_clear */
@@ -2504,4 +2506,3 @@ static PyObject _dummy_struct = {
   _PyObject_EXTRA_INIT
   2, &_PySetDummy_Type
 };
-

Objects/tupleobject.c

@@ -917,7 +917,8 @@ PyTypeObject PyTuple_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS, /* tp_flags */
+        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     tuple_new__doc__,                           /* tp_doc */
     (traverseproc)tupletraverse,                /* tp_traverse */
     0,                                          /* tp_clear */

Objects/typeobject.c

@@ -5261,6 +5261,10 @@ inherit_special(PyTypeObject *type, PyTypeObject *base)
         type->tp_flags |= Py_TPFLAGS_LIST_SUBCLASS;
     else if (PyType_IsSubtype(base, &PyDict_Type))
         type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
+
+    if (PyType_HasFeature(base, _Py_TPFLAGS_MATCH_SELF)) {
+        type->tp_flags |= _Py_TPFLAGS_MATCH_SELF;
+    }
 }
 
 static int

Objects/unicodeobject.c

@@ -15657,7 +15657,8 @@ PyTypeObject PyUnicode_Type = {
     0,                            /* tp_setattro */
     0,                            /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-    Py_TPFLAGS_UNICODE_SUBCLASS,   /* tp_flags */
+        Py_TPFLAGS_UNICODE_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF, /* tp_flags */
     unicode_doc,                  /* tp_doc */
     0,                            /* tp_traverse */
     0,                            /* tp_clear */

Parser/Python.asdl

@@ -36,6 +36,8 @@ module Python
           | With(withitem* items, stmt* body, string? type_comment)
           | AsyncWith(withitem* items, stmt* body, string? type_comment)
 
+          | Match(expr subject, match_case* cases)
+
           | Raise(expr? exc, expr? cause)
           | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
           | Assert(expr test, expr? msg)
@@ -87,6 +89,10 @@ module Python
          -- can appear only in Subscript
          | Slice(expr? lower, expr? upper, expr? step)
 
+         -- only used in patterns
+         | MatchAs(expr pattern, identifier name)
+         | MatchOr(expr* patterns)
+
           -- col_offset is the byte offset in the utf8 string the parser uses
           attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
 
@@ -121,5 +127,7 @@ module Python
 
     withitem = (expr context_expr, expr? optional_vars)
 
+    match_case = (expr pattern, expr? guard, stmt* body)
+
     type_ignore = TypeIgnore(int lineno, string tag)
 }

Parser/asdl_c.py

@@ -872,9 +872,10 @@ make_type(struct ast_state *state, const char *type, PyObject* base,
         }
         PyTuple_SET_ITEM(fnames, i, field);
     }
-    result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){OOOOOs}",
+    result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){OOOOOOOs}",
                     type, base,
                     state->_fields, fnames,
+                    state->__match_args__, fnames,
                     state->__module__,
                     state->ast,
                     state->__doc__, doc);
@@ -1005,6 +1006,7 @@ static int add_ast_fields(struct ast_state *state)
     empty_tuple = PyTuple_New(0);
     if (!empty_tuple ||
         PyObject_SetAttrString(state->AST_type, "_fields", empty_tuple) < 0 ||
+        PyObject_SetAttrString(state->AST_type, "__match_args__", empty_tuple) < 0 ||
         PyObject_SetAttrString(state->AST_type, "_attributes", empty_tuple) < 0) {
         Py_XDECREF(empty_tuple);
         return -1;
@@ -1405,6 +1407,7 @@ def generate_module_def(mod, f, internal_h):
     state_strings = {
         "ast",
         "_fields",
+        "__match_args__",
         "__doc__",
         "__dict__",
         "__module__",

Python/Python-ast.c

@@ -91,6 +91,9 @@ struct ast_state {
     PyObject *Lt_type;
     PyObject *MatMult_singleton;
     PyObject *MatMult_type;
+    PyObject *MatchAs_type;
+    PyObject *MatchOr_type;
+    PyObject *Match_type;
     PyObject *Mod_singleton;
     PyObject *Mod_type;
     PyObject *Module_type;
@@ -137,6 +140,7 @@ struct ast_state {
     PyObject *Yield_type;
     PyObject *__dict__;
     PyObject *__doc__;
+    PyObject *__match_args__;
     PyObject *__module__;
     PyObject *_attributes;
     PyObject *_fields;
@@ -153,6 +157,7 @@ struct ast_state {
     PyObject *bases;
     PyObject *body;
     PyObject *boolop_type;
+    PyObject *cases;
     PyObject *cause;
     PyObject *cmpop_type;
     PyObject *col_offset;
@@ -175,6 +180,7 @@ struct ast_state {
     PyObject *format_spec;
     PyObject *func;
     PyObject *generators;
+    PyObject *guard;
     PyObject *handlers;
     PyObject *id;
     PyObject *ifs;
@@ -193,6 +199,7 @@ struct ast_state {
     PyObject *level;
     PyObject *lineno;
     PyObject *lower;
+    PyObject *match_case_type;
     PyObject *mod_type;
     PyObject *module;
     PyObject *msg;
@@ -204,6 +211,8 @@ struct ast_state {
     PyObject *ops;
     PyObject *optional_vars;
     PyObject *orelse;
+    PyObject *pattern;
+    PyObject *patterns;
     PyObject *posonlyargs;
     PyObject *returns;
     PyObject *right;
@@ -211,6 +220,7 @@ struct ast_state {
     PyObject *slice;
     PyObject *step;
     PyObject *stmt_type;
+    PyObject *subject;
     PyObject *tag;
     PyObject *target;
     PyObject *targets;
@@ -348,6 +358,9 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->Lt_type);
     Py_CLEAR(state->MatMult_singleton);
     Py_CLEAR(state->MatMult_type);
+    Py_CLEAR(state->MatchAs_type);
+    Py_CLEAR(state->MatchOr_type);
+    Py_CLEAR(state->Match_type);
     Py_CLEAR(state->Mod_singleton);
     Py_CLEAR(state->Mod_type);
     Py_CLEAR(state->Module_type);
@@ -394,6 +407,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->Yield_type);
     Py_CLEAR(state->__dict__);
     Py_CLEAR(state->__doc__);
+    Py_CLEAR(state->__match_args__);
     Py_CLEAR(state->__module__);
     Py_CLEAR(state->_attributes);
     Py_CLEAR(state->_fields);
@@ -410,6 +424,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->bases);
     Py_CLEAR(state->body);
     Py_CLEAR(state->boolop_type);
+    Py_CLEAR(state->cases);
     Py_CLEAR(state->cause);
     Py_CLEAR(state->cmpop_type);
     Py_CLEAR(state->col_offset);
@@ -432,6 +447,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->format_spec);
     Py_CLEAR(state->func);
     Py_CLEAR(state->generators);
+    Py_CLEAR(state->guard);
     Py_CLEAR(state->handlers);
     Py_CLEAR(state->id);
     Py_CLEAR(state->ifs);
@@ -450,6 +466,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->level);
     Py_CLEAR(state->lineno);
     Py_CLEAR(state->lower);
+    Py_CLEAR(state->match_case_type);
     Py_CLEAR(state->mod_type);
     Py_CLEAR(state->module);
     Py_CLEAR(state->msg);
@@ -461,6 +478,8 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->ops);
     Py_CLEAR(state->optional_vars);
     Py_CLEAR(state->orelse);
+    Py_CLEAR(state->pattern);
+    Py_CLEAR(state->patterns);
     Py_CLEAR(state->posonlyargs);
     Py_CLEAR(state->returns);
     Py_CLEAR(state->right);
@@ -468,6 +487,7 @@ void _PyAST_Fini(PyInterpreterState *interp)
     Py_CLEAR(state->slice);
     Py_CLEAR(state->step);
     Py_CLEAR(state->stmt_type);
+    Py_CLEAR(state->subject);
     Py_CLEAR(state->tag);
     Py_CLEAR(state->target);
     Py_CLEAR(state->targets);
@@ -494,6 +514,7 @@ static int init_identifiers(struct ast_state *state)
 {
     if ((state->__dict__ = PyUnicode_InternFromString("__dict__")) == NULL) return 0;
     if ((state->__doc__ = PyUnicode_InternFromString("__doc__")) == NULL) return 0;
+    if ((state->__match_args__ = PyUnicode_InternFromString("__match_args__")) == NULL) return 0;
     if ((state->__module__ = PyUnicode_InternFromString("__module__")) == NULL) return 0;
     if ((state->_attributes = PyUnicode_InternFromString("_attributes")) == NULL) return 0;
     if ((state->_fields = PyUnicode_InternFromString("_fields")) == NULL) return 0;
@@ -506,6 +527,7 @@ static int init_identifiers(struct ast_state *state)
     if ((state->attr = PyUnicode_InternFromString("attr")) == NULL) return 0;
     if ((state->bases = PyUnicode_InternFromString("bases")) == NULL) return 0;
     if ((state->body = PyUnicode_InternFromString("body")) == NULL) return 0;
+    if ((state->cases = PyUnicode_InternFromString("cases")) == NULL) return 0;
     if ((state->cause = PyUnicode_InternFromString("cause")) == NULL) return 0;
     if ((state->col_offset = PyUnicode_InternFromString("col_offset")) == NULL) return 0;
     if ((state->comparators = PyUnicode_InternFromString("comparators")) == NULL) return 0;
@@ -523,6 +545,7 @@ static int init_identifiers(struct ast_state *state)
     if ((state->format_spec = PyUnicode_InternFromString("format_spec")) == NULL) return 0;
     if ((state->func = PyUnicode_InternFromString("func")) == NULL) return 0;
     if ((state->generators = PyUnicode_InternFromString("generators")) == NULL) return 0;
+    if ((state->guard = PyUnicode_InternFromString("guard")) == NULL) return 0;
     if ((state->handlers = PyUnicode_InternFromString("handlers")) == NULL) return 0;
     if ((state->id = PyUnicode_InternFromString("id")) == NULL) return 0;
     if ((state->ifs = PyUnicode_InternFromString("ifs")) == NULL) return 0;
@@ -549,12 +572,15 @@ static int init_identifiers(struct ast_state *state)
     if ((state->ops = PyUnicode_InternFromString("ops")) == NULL) return 0;
     if ((state->optional_vars = PyUnicode_InternFromString("optional_vars")) == NULL) return 0;
     if ((state->orelse = PyUnicode_InternFromString("orelse")) == NULL) return 0;
+    if ((state->pattern = PyUnicode_InternFromString("pattern")) == NULL) return 0;
+    if ((state->patterns = PyUnicode_InternFromString("patterns")) == NULL) return 0;
     if ((state->posonlyargs = PyUnicode_InternFromString("posonlyargs")) == NULL) return 0;
     if ((state->returns = PyUnicode_InternFromString("returns")) == NULL) return 0;
     if ((state->right = PyUnicode_InternFromString("right")) == NULL) return 0;
     if ((state->simple = PyUnicode_InternFromString("simple")) == NULL) return 0;
     if ((state->slice = PyUnicode_InternFromString("slice")) == NULL) return 0;
     if ((state->step = PyUnicode_InternFromString("step")) == NULL) return 0;
+    if ((state->subject = PyUnicode_InternFromString("subject")) == NULL) return 0;
     if ((state->tag = PyUnicode_InternFromString("tag")) == NULL) return 0;
     if ((state->target = PyUnicode_InternFromString("target")) == NULL) return 0;
     if ((state->targets = PyUnicode_InternFromString("targets")) == NULL) return 0;
@@ -579,6 +605,7 @@ GENERATE_ASDL_SEQ_CONSTRUCTOR(arg, arg_ty)
 GENERATE_ASDL_SEQ_CONSTRUCTOR(keyword, keyword_ty)
 GENERATE_ASDL_SEQ_CONSTRUCTOR(alias, alias_ty)
 GENERATE_ASDL_SEQ_CONSTRUCTOR(withitem, withitem_ty)
+GENERATE_ASDL_SEQ_CONSTRUCTOR(match_case, match_case_ty)
 GENERATE_ASDL_SEQ_CONSTRUCTOR(type_ignore, type_ignore_ty)
 
 static PyObject* ast2obj_mod(struct ast_state *state, void*);
@@ -682,6 +709,10 @@ static const char * const AsyncWith_fields[]={
     "body",
     "type_comment",
 };
+static const char * const Match_fields[]={
+    "subject",
+    "cases",
+};
 static const char * const Raise_fields[]={
     "exc",
     "cause",
@@ -832,6 +863,13 @@ static const char * const Slice_fields[]={
     "upper",
     "step",
 };
+static const char * const MatchAs_fields[]={
+    "pattern",
+    "name",
+};
+static const char * const MatchOr_fields[]={
+    "patterns",
+};
 static PyObject* ast2obj_expr_context(struct ast_state *state, expr_context_ty);
 static PyObject* ast2obj_boolop(struct ast_state *state, boolop_ty);
 static PyObject* ast2obj_operator(struct ast_state *state, operator_ty);
@@ -899,6 +937,12 @@ static const char * const withitem_fields[]={
     "context_expr",
     "optional_vars",
 };
+static PyObject* ast2obj_match_case(struct ast_state *state, void*);
+static const char * const match_case_fields[]={
+    "pattern",
+    "guard",
+    "body",
+};
 static PyObject* ast2obj_type_ignore(struct ast_state *state, void*);
 static const char * const TypeIgnore_fields[]={
     "lineno",
@@ -1089,9 +1133,10 @@ make_type(struct ast_state *state, const char *type, PyObject* base,
         }
         PyTuple_SET_ITEM(fnames, i, field);
     }
-    result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){OOOOOs}",
+    result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){OOOOOOOs}",
                     type, base,
                     state->_fields, fnames,
+                    state->__match_args__, fnames,
                     state->__module__,
                     state->ast,
                     state->__doc__, doc);
@@ -1222,6 +1267,7 @@ static int add_ast_fields(struct ast_state *state)
     empty_tuple = PyTuple_New(0);
     if (!empty_tuple ||
         PyObject_SetAttrString(state->AST_type, "_fields", empty_tuple) < 0 ||
+        PyObject_SetAttrString(state->AST_type, "__match_args__", empty_tuple) < 0 ||
         PyObject_SetAttrString(state->AST_type, "_attributes", empty_tuple) < 0) {
         Py_XDECREF(empty_tuple);
         return -1;
@@ -1291,6 +1337,7 @@ init_types(struct ast_state *state)
         "     | If(expr test, stmt* body, stmt* orelse)\n"
         "     | With(withitem* items, stmt* body, string? type_comment)\n"
         "     | AsyncWith(withitem* items, stmt* body, string? type_comment)\n"
+        "     | Match(expr subject, match_case* cases)\n"
         "     | Raise(expr? exc, expr? cause)\n"
         "     | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)\n"
         "     | Assert(expr test, expr? msg)\n"
@@ -1393,6 +1440,10 @@ init_types(struct ast_state *state)
     if (PyObject_SetAttr(state->AsyncWith_type, state->type_comment, Py_None)
         == -1)
         return 0;
+    state->Match_type = make_type(state, "Match", state->stmt_type,
+                                  Match_fields, 2,
+        "Match(expr subject, match_case* cases)");
+    if (!state->Match_type) return 0;
     state->Raise_type = make_type(state, "Raise", state->stmt_type,
                                   Raise_fields, 2,
         "Raise(expr? exc, expr? cause)");
@@ -1471,7 +1522,9 @@ init_types(struct ast_state *state)
         "     | Name(identifier id, expr_context ctx)\n"
         "     | List(expr* elts, expr_context ctx)\n"
         "     | Tuple(expr* elts, expr_context ctx)\n"
-        "     | Slice(expr? lower, expr? upper, expr? step)");
+        "     | Slice(expr? lower, expr? upper, expr? step)\n"
+        "     | MatchAs(expr pattern, identifier name)\n"
+        "     | MatchOr(expr* patterns)");
     if (!state->expr_type) return 0;
     if (!add_attributes(state, state->expr_type, expr_attributes, 4)) return 0;
     if (PyObject_SetAttr(state->expr_type, state->end_lineno, Py_None) == -1)
@@ -1604,6 +1657,14 @@ init_types(struct ast_state *state)
         return 0;
     if (PyObject_SetAttr(state->Slice_type, state->step, Py_None) == -1)
         return 0;
+    state->MatchAs_type = make_type(state, "MatchAs", state->expr_type,
+                                    MatchAs_fields, 2,
+        "MatchAs(expr pattern, identifier name)");
+    if (!state->MatchAs_type) return 0;
+    state->MatchOr_type = make_type(state, "MatchOr", state->expr_type,
+                                    MatchOr_fields, 1,
+        "MatchOr(expr* patterns)");
+    if (!state->MatchOr_type) return 0;
     state->expr_context_type = make_type(state, "expr_context",
                                          state->AST_type, NULL, 0,
         "expr_context = Load | Store | Del");
@@ -1910,6 +1971,13 @@ init_types(struct ast_state *state)
     if (PyObject_SetAttr(state->withitem_type, state->optional_vars, Py_None)
         == -1)
         return 0;
+    state->match_case_type = make_type(state, "match_case", state->AST_type,
+                                       match_case_fields, 3,
+        "match_case(expr pattern, expr? guard, stmt* body)");
+    if (!state->match_case_type) return 0;
+    if (!add_attributes(state, state->match_case_type, NULL, 0)) return 0;
+    if (PyObject_SetAttr(state->match_case_type, state->guard, Py_None) == -1)
+        return 0;
     state->type_ignore_type = make_type(state, "type_ignore", state->AST_type,
                                         NULL, 0,
         "type_ignore = TypeIgnore(int lineno, string tag)");
@@ -1955,6 +2023,8 @@ static int obj2ast_alias(struct ast_state *state, PyObject* obj, alias_ty* out,
                          PyArena* arena);
 static int obj2ast_withitem(struct ast_state *state, PyObject* obj,
                             withitem_ty* out, PyArena* arena);
+static int obj2ast_match_case(struct ast_state *state, PyObject* obj,
+                              match_case_ty* out, PyArena* arena);
 static int obj2ast_type_ignore(struct ast_state *state, PyObject* obj,
                                type_ignore_ty* out, PyArena* arena);
 
@@ -2388,6 +2458,29 @@ AsyncWith(asdl_withitem_seq * items, asdl_stmt_seq * body, string type_comment,
     return p;
 }
 
+stmt_ty
+Match(expr_ty subject, asdl_match_case_seq * cases, int lineno, int col_offset,
+      int end_lineno, int end_col_offset, PyArena *arena)
+{
+    stmt_ty p;
+    if (!subject) {
+        PyErr_SetString(PyExc_ValueError,
+                        "field 'subject' is required for Match");
+        return NULL;
+    }
+    p = (stmt_ty)PyArena_Malloc(arena, sizeof(*p));
+    if (!p)
+        return NULL;
+    p->kind = Match_kind;
+    p->v.Match.subject = subject;
+    p->v.Match.cases = cases;
+    p->lineno = lineno;
+    p->col_offset = col_offset;
+    p->end_lineno = end_lineno;
+    p->end_col_offset = end_col_offset;
+    return p;
+}
+
 stmt_ty
 Raise(expr_ty exc, expr_ty cause, int lineno, int col_offset, int end_lineno,
       int end_col_offset, PyArena *arena)
@@ -3263,6 +3356,51 @@ Slice(expr_ty lower, expr_ty upper, expr_ty step, int lineno, int col_offset,
     return p;
 }
 
+expr_ty
+MatchAs(expr_ty pattern, identifier name, int lineno, int col_offset, int
+        end_lineno, int end_col_offset, PyArena *arena)
+{
+    expr_ty p;
+    if (!pattern) {
+        PyErr_SetString(PyExc_ValueError,
+                        "field 'pattern' is required for MatchAs");
+        return NULL;
+    }
+    if (!name) {
+        PyErr_SetString(PyExc_ValueError,
+                        "field 'name' is required for MatchAs");
+        return NULL;
+    }
+    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+    if (!p)
+        return NULL;
+    p->kind = MatchAs_kind;
+    p->v.MatchAs.pattern = pattern;
+    p->v.MatchAs.name = name;
+    p->lineno = lineno;
+    p->col_offset = col_offset;
+    p->end_lineno = end_lineno;
+    p->end_col_offset = end_col_offset;
+    return p;
+}
+
+expr_ty
+MatchOr(asdl_expr_seq * patterns, int lineno, int col_offset, int end_lineno,
+        int end_col_offset, PyArena *arena)
+{
+    expr_ty p;
+    p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+    if (!p)
+        return NULL;
+    p->kind = MatchOr_kind;
+    p->v.MatchOr.patterns = patterns;
+    p->lineno = lineno;
+    p->col_offset = col_offset;
+    p->end_lineno = end_lineno;
+    p->end_col_offset = end_col_offset;
+    return p;
+}
+
 comprehension_ty
 comprehension(expr_ty target, expr_ty iter, asdl_expr_seq * ifs, int is_async,
               PyArena *arena)
@@ -3406,6 +3544,24 @@ withitem(expr_ty context_expr, expr_ty optional_vars, PyArena *arena)
     return p;
 }
 
+match_case_ty
+match_case(expr_ty pattern, expr_ty guard, asdl_stmt_seq * body, PyArena *arena)
+{
+    match_case_ty p;
+    if (!pattern) {
+        PyErr_SetString(PyExc_ValueError,
+                        "field 'pattern' is required for match_case");
+        return NULL;
+    }
+    p = (match_case_ty)PyArena_Malloc(arena, sizeof(*p));
+    if (!p)
+        return NULL;
+    p->pattern = pattern;
+    p->guard = guard;
+    p->body = body;
+    return p;
+}
+
 type_ignore_ty
 TypeIgnore(int lineno, string tag, PyArena *arena)
 {
@@ -3847,6 +4003,22 @@ ast2obj_stmt(struct ast_state *state, void* _o)
             goto failed;
         Py_DECREF(value);
         break;
+    case Match_kind:
+        tp = (PyTypeObject *)state->Match_type;
+        result = PyType_GenericNew(tp, NULL, NULL);
+        if (!result) goto failed;
+        value = ast2obj_expr(state, o->v.Match.subject);
+        if (!value) goto failed;
+        if (PyObject_SetAttr(result, state->subject, value) == -1)
+            goto failed;
+        Py_DECREF(value);
+        value = ast2obj_list(state, (asdl_seq*)o->v.Match.cases,
+                             ast2obj_match_case);
+        if (!value) goto failed;
+        if (PyObject_SetAttr(result, state->cases, value) == -1)
+            goto failed;
+        Py_DECREF(value);
+        break;
     case Raise_kind:
         tp = (PyTypeObject *)state->Raise_type;
         result = PyType_GenericNew(tp, NULL, NULL);
@@ -4460,6 +4632,32 @@ ast2obj_expr(struct ast_state *state, void* _o)
             goto failed;
         Py_DECREF(value);
         break;
+    case MatchAs_kind:
+        tp = (PyTypeObject *)state->MatchAs_type;
+        result = PyType_GenericNew(tp, NULL, NULL);
+        if (!result) goto failed;
+        value = ast2obj_expr(state, o->v.MatchAs.pattern);
+        if (!value) goto failed;
+        if (PyObject_SetAttr(result, state->pattern, value) == -1)
+            goto failed;
+        Py_DECREF(value);
+        value = ast2obj_identifier(state, o->v.MatchAs.name);
+        if (!value) goto failed;
+        if (PyObject_SetAttr(result, state->name, value) == -1)
+            goto failed;
+        Py_DECREF(value);
+        break;
+    case MatchOr_kind:
+        tp = (PyTypeObject *)state->MatchOr_type;
+        result = PyType_GenericNew(tp, NULL, NULL);
+        if (!result) goto failed;
+        value = ast2obj_list(state, (asdl_seq*)o->v.MatchOr.patterns,
+                             ast2obj_expr);
+        if (!value) goto failed;
+        if (PyObject_SetAttr(result, state->patterns, value) == -1)
+            goto failed;
+        Py_DECREF(value);
+        break;
     }
     value = ast2obj_int(state, o->lineno);
     if (!value) goto failed;
@@ -4927,6 +5125,40 @@ failed:
     return NULL;
 }
 
+PyObject*
+ast2obj_match_case(struct ast_state *state, void* _o)
+{
+    match_case_ty o = (match_case_ty)_o;
+    PyObject *result = NULL, *value = NULL;
+    PyTypeObject *tp;
+    if (!o) {
+        Py_RETURN_NONE;
+    }
+    tp = (PyTypeObject *)state->match_case_type;
+    result = PyType_GenericNew(tp, NULL, NULL);
+    if (!result) return NULL;
+    value = ast2obj_expr(state, o->pattern);
+    if (!value) goto failed;
+    if (PyObject_SetAttr(result, state->pattern, value) == -1)
+        goto failed;
+    Py_DECREF(value);
+    value = ast2obj_expr(state, o->guard);
+    if (!value) goto failed;
+    if (PyObject_SetAttr(result, state->guard, value) == -1)
+        goto failed;
+    Py_DECREF(value);
+    value = ast2obj_list(state, (asdl_seq*)o->body, ast2obj_stmt);
+    if (!value) goto failed;
+    if (PyObject_SetAttr(result, state->body, value) == -1)
+        goto failed;
+    Py_DECREF(value);
+    return result;
+failed:
+    Py_XDECREF(value);
+    Py_XDECREF(result);
+    return NULL;
+}
+
 PyObject*
 ast2obj_type_ignore(struct ast_state *state, void* _o)
 {
@@ -6581,6 +6813,66 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, PyArena*
         if (*out == NULL) goto failed;
         return 0;
     }
+    tp = state->Match_type;
+    isinstance = PyObject_IsInstance(obj, tp);
+    if (isinstance == -1) {
+        return 1;
+    }
+    if (isinstance) {
+        expr_ty subject;
+        asdl_match_case_seq* cases;
+
+        if (_PyObject_LookupAttr(obj, state->subject, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL) {
+            PyErr_SetString(PyExc_TypeError, "required field \"subject\" missing from Match");
+            return 1;
+        }
+        else {
+            int res;
+            res = obj2ast_expr(state, tmp, &subject, arena);
+            if (res != 0) goto failed;
+            Py_CLEAR(tmp);
+        }
+        if (_PyObject_LookupAttr(obj, state->cases, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL) {
+            PyErr_SetString(PyExc_TypeError, "required field \"cases\" missing from Match");
+            return 1;
+        }
+        else {
+            int res;
+            Py_ssize_t len;
+            Py_ssize_t i;
+            if (!PyList_Check(tmp)) {
+                PyErr_Format(PyExc_TypeError, "Match field \"cases\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                goto failed;
+            }
+            len = PyList_GET_SIZE(tmp);
+            cases = _Py_asdl_match_case_seq_new(len, arena);
+            if (cases == NULL) goto failed;
+            for (i = 0; i < len; i++) {
+                match_case_ty val;
+                PyObject *tmp2 = PyList_GET_ITEM(tmp, i);
+                Py_INCREF(tmp2);
+                res = obj2ast_match_case(state, tmp2, &val, arena);
+                Py_DECREF(tmp2);
+                if (res != 0) goto failed;
+                if (len != PyList_GET_SIZE(tmp)) {
+                    PyErr_SetString(PyExc_RuntimeError, "Match field \"cases\" changed size during iteration");
+                    goto failed;
+                }
+                asdl_seq_SET(cases, i, val);
+            }
+            Py_CLEAR(tmp);
+        }
+        *out = Match(subject, cases, lineno, col_offset, end_lineno,
+                     end_col_offset, arena);
+        if (*out == NULL) goto failed;
+        return 0;
+    }
     tp = state->Raise_type;
     isinstance = PyObject_IsInstance(obj, tp);
     if (isinstance == -1) {
@@ -8591,6 +8883,92 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, PyArena*
         if (*out == NULL) goto failed;
         return 0;
     }
+    tp = state->MatchAs_type;
+    isinstance = PyObject_IsInstance(obj, tp);
+    if (isinstance == -1) {
+        return 1;
+    }
+    if (isinstance) {
+        expr_ty pattern;
+        identifier name;
+
+        if (_PyObject_LookupAttr(obj, state->pattern, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL) {
+            PyErr_SetString(PyExc_TypeError, "required field \"pattern\" missing from MatchAs");
+            return 1;
+        }
+        else {
+            int res;
+            res = obj2ast_expr(state, tmp, &pattern, arena);
+            if (res != 0) goto failed;
+            Py_CLEAR(tmp);
+        }
+        if (_PyObject_LookupAttr(obj, state->name, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL) {
+            PyErr_SetString(PyExc_TypeError, "required field \"name\" missing from MatchAs");
+            return 1;
+        }
+        else {
+            int res;
+            res = obj2ast_identifier(state, tmp, &name, arena);
+            if (res != 0) goto failed;
+            Py_CLEAR(tmp);
+        }
+        *out = MatchAs(pattern, name, lineno, col_offset, end_lineno,
+                       end_col_offset, arena);
+        if (*out == NULL) goto failed;
+        return 0;
+    }
+    tp = state->MatchOr_type;
+    isinstance = PyObject_IsInstance(obj, tp);
+    if (isinstance == -1) {
+        return 1;
+    }
+    if (isinstance) {
+        asdl_expr_seq* patterns;
+
+        if (_PyObject_LookupAttr(obj, state->patterns, &tmp) < 0) {
+            return 1;
+        }
+        if (tmp == NULL) {
+            PyErr_SetString(PyExc_TypeError, "required field \"patterns\" missing from MatchOr");
+            return 1;
+        }
+        else {
+            int res;
+            Py_ssize_t len;
+            Py_ssize_t i;
+            if (!PyList_Check(tmp)) {
+                PyErr_Format(PyExc_TypeError, "MatchOr field \"patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                goto failed;
+            }
+            len = PyList_GET_SIZE(tmp);
+            patterns = _Py_asdl_expr_seq_new(len, arena);
+            if (patterns == NULL) goto failed;
+            for (i = 0; i < len; i++) {
+                expr_ty val;
+                PyObject *tmp2 = PyList_GET_ITEM(tmp, i);
+                Py_INCREF(tmp2);
+                res = obj2ast_expr(state, tmp2, &val, arena);
+                Py_DECREF(tmp2);
+                if (res != 0) goto failed;
+                if (len != PyList_GET_SIZE(tmp)) {
+                    PyErr_SetString(PyExc_RuntimeError, "MatchOr field \"patterns\" changed size during iteration");
+                    goto failed;
+                }
+                asdl_seq_SET(patterns, i, val);
+            }
+            Py_CLEAR(tmp);
+        }
+        *out = MatchOr(patterns, lineno, col_offset, end_lineno,
+                       end_col_offset, arena);
+        if (*out == NULL) goto failed;
+        return 0;
+    }
 
     PyErr_Format(PyExc_TypeError, "expected some sort of expr, but got %R", obj);
     failed:
@@ -9651,6 +10029,81 @@ failed:
     return 1;
 }
 
+int
+obj2ast_match_case(struct ast_state *state, PyObject* obj, match_case_ty* out,
+                   PyArena* arena)
+{
+    PyObject* tmp = NULL;
+    expr_ty pattern;
+    expr_ty guard;
+    asdl_stmt_seq* body;
+
+    if (_PyObject_LookupAttr(obj, state->pattern, &tmp) < 0) {
+        return 1;
+    }
+    if (tmp == NULL) {
+        PyErr_SetString(PyExc_TypeError, "required field \"pattern\" missing from match_case");
+        return 1;
+    }
+    else {
+        int res;
+        res = obj2ast_expr(state, tmp, &pattern, arena);
+        if (res != 0) goto failed;
+        Py_CLEAR(tmp);
+    }
+    if (_PyObject_LookupAttr(obj, state->guard, &tmp) < 0) {
+        return 1;
+    }
+    if (tmp == NULL || tmp == Py_None) {
+        Py_CLEAR(tmp);
+        guard = NULL;
+    }
+    else {
+        int res;
+        res = obj2ast_expr(state, tmp, &guard, arena);
+        if (res != 0) goto failed;
+        Py_CLEAR(tmp);
+    }
+    if (_PyObject_LookupAttr(obj, state->body, &tmp) < 0) {
+        return 1;
+    }
+    if (tmp == NULL) {
+        PyErr_SetString(PyExc_TypeError, "required field \"body\" missing from match_case");
+        return 1;
+    }
+    else {
+        int res;
+        Py_ssize_t len;
+        Py_ssize_t i;
+        if (!PyList_Check(tmp)) {
+            PyErr_Format(PyExc_TypeError, "match_case field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            goto failed;
+        }
+        len = PyList_GET_SIZE(tmp);
+        body = _Py_asdl_stmt_seq_new(len, arena);
+        if (body == NULL) goto failed;
+        for (i = 0; i < len; i++) {
+            stmt_ty val;
+            PyObject *tmp2 = PyList_GET_ITEM(tmp, i);
+            Py_INCREF(tmp2);
+            res = obj2ast_stmt(state, tmp2, &val, arena);
+            Py_DECREF(tmp2);
+            if (res != 0) goto failed;
+            if (len != PyList_GET_SIZE(tmp)) {
+                PyErr_SetString(PyExc_RuntimeError, "match_case field \"body\" changed size during iteration");
+                goto failed;
+            }
+            asdl_seq_SET(body, i, val);
+        }
+        Py_CLEAR(tmp);
+    }
+    *out = match_case(pattern, guard, body, arena);
+    return 0;
+failed:
+    Py_XDECREF(tmp);
+    return 1;
+}
+
 int
 obj2ast_type_ignore(struct ast_state *state, PyObject* obj, type_ignore_ty*
                     out, PyArena* arena)
@@ -9792,6 +10245,9 @@ astmodule_exec(PyObject *m)
     if (PyModule_AddObjectRef(m, "AsyncWith", state->AsyncWith_type) < 0) {
         return -1;
     }
+    if (PyModule_AddObjectRef(m, "Match", state->Match_type) < 0) {
+        return -1;
+    }
     if (PyModule_AddObjectRef(m, "Raise", state->Raise_type) < 0) {
         return -1;
     }
@@ -9911,6 +10367,12 @@ astmodule_exec(PyObject *m)
     if (PyModule_AddObjectRef(m, "Slice", state->Slice_type) < 0) {
         return -1;
     }
+    if (PyModule_AddObjectRef(m, "MatchAs", state->MatchAs_type) < 0) {
+        return -1;
+    }
+    if (PyModule_AddObjectRef(m, "MatchOr", state->MatchOr_type) < 0) {
+        return -1;
+    }
     if (PyModule_AddObjectRef(m, "expr_context", state->expr_context_type) < 0)
         {
         return -1;
@@ -10050,6 +10512,9 @@ astmodule_exec(PyObject *m)
     if (PyModule_AddObjectRef(m, "withitem", state->withitem_type) < 0) {
         return -1;
     }
+    if (PyModule_AddObjectRef(m, "match_case", state->match_case_type) < 0) {
+        return -1;
+    }
     if (PyModule_AddObjectRef(m, "type_ignore", state->type_ignore_type) < 0) {
         return -1;
     }

Python/ast.c

@@ -309,6 +309,14 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
         return validate_exprs(exp->v.Tuple.elts, ctx, 0);
     case NamedExpr_kind:
         return validate_expr(exp->v.NamedExpr.value, Load);
+    case MatchAs_kind:
+        PyErr_SetString(PyExc_ValueError,
+                        "MatchAs is only valid in match_case patterns");
+        return 0;
+    case MatchOr_kind:
+        PyErr_SetString(PyExc_ValueError,
+                        "MatchOr is only valid in match_case patterns");
+        return 0;
     /* This last case doesn't have any checking. */
     case Name_kind:
         return 1;
@@ -317,6 +325,13 @@ validate_expr(expr_ty exp, expr_context_ty ctx)
     return 0;
 }
 
+static int
+validate_pattern(expr_ty p)
+{
+    // Coming soon (thanks Batuhan)!
+    return 1;
+}
+
 static int
 _validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
 {
@@ -415,6 +430,20 @@ validate_stmt(stmt_ty stmt)
                 return 0;
         }
         return validate_body(stmt->v.AsyncWith.body, "AsyncWith");
+    case Match_kind:
+        if (!validate_expr(stmt->v.Match.subject, Load)
+            || !validate_nonempty_seq(stmt->v.Match.cases, "cases", "Match")) {
+            return 0;
+        }
+        for (i = 0; i < asdl_seq_LEN(stmt->v.Match.cases); i++) {
+            match_case_ty m = asdl_seq_GET(stmt->v.Match.cases, i);
+            if (!validate_pattern(m->pattern)
+                || (m->guard && !validate_expr(m->guard, Load))
+                || !validate_body(m->body, "match_case")) {
+                return 0;
+            }
+        }
+        return 1;
     case Raise_kind:
         if (stmt->v.Raise.exc) {
             return validate_expr(stmt->v.Raise.exc, Load) &&

Python/ast_opt.c

@@ -408,6 +408,9 @@ static int astfold_comprehension(comprehension_ty node_, PyArena *ctx_, _PyASTOp
 static int astfold_keyword(keyword_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
 static int astfold_withitem(withitem_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
 static int astfold_excepthandler(excepthandler_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
+static int astfold_match_case(match_case_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
+static int astfold_pattern(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
+
 #define CALL(FUNC, TYPE, ARG) \
     if (!FUNC((ARG), ctx_, state)) \
         return 0;
@@ -590,6 +593,10 @@ astfold_expr(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
     case Constant_kind:
         // Already a constant, nothing further to do
         break;
+    case MatchAs_kind:
+    case MatchOr_kind:
+        // These can't occur outside of patterns.
+        Py_UNREACHABLE();
     // No default case, so the compiler will emit a warning if new expression
     // kinds are added without being handled here
     }
@@ -709,6 +716,10 @@ astfold_stmt(stmt_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
     case Expr_kind:
         CALL(astfold_expr, expr_ty, node_->v.Expr.value);
         break;
+    case Match_kind:
+        CALL(astfold_expr, expr_ty, node_->v.Match.subject);
+        CALL_SEQ(astfold_match_case, match_case, node_->v.Match.cases);
+        break;
     // The following statements don't contain any subexpressions to be folded
     case Import_kind:
     case ImportFrom_kind:
@@ -746,6 +757,125 @@ astfold_withitem(withitem_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
     return 1;
 }
 
+static int
+astfold_pattern_negative(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    assert(node_->kind == UnaryOp_kind);
+    assert(node_->v.UnaryOp.op == USub);
+    assert(node_->v.UnaryOp.operand->kind == Constant_kind);
+    PyObject *value = node_->v.UnaryOp.operand->v.Constant.value;
+    assert(PyComplex_CheckExact(value) ||
+           PyFloat_CheckExact(value) ||
+           PyLong_CheckExact(value));
+    PyObject *negated = PyNumber_Negative(value);
+    if (negated == NULL) {
+        return 0;
+    }
+    assert(PyComplex_CheckExact(negated) ||
+           PyFloat_CheckExact(negated) ||
+           PyLong_CheckExact(negated));
+    return make_const(node_, negated, ctx_);
+}
+
+static int
+astfold_pattern_complex(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    expr_ty left = node_->v.BinOp.left;
+    expr_ty right = node_->v.BinOp.right;
+    if (left->kind == UnaryOp_kind) {
+        CALL(astfold_pattern_negative, expr_ty, left);
+    }
+    assert(left->kind = Constant_kind);
+    assert(right->kind = Constant_kind);
+    // LHS must be real, RHS must be imaginary:
+    if (!(PyFloat_CheckExact(left->v.Constant.value) ||
+          PyLong_CheckExact(left->v.Constant.value)) ||
+        !PyComplex_CheckExact(right->v.Constant.value))
+    {
+        // Not actually valid, but it's the compiler's job to complain:
+        return 1;
+    }
+    PyObject *new;
+    if (node_->v.BinOp.op == Add) {
+        new = PyNumber_Add(left->v.Constant.value, right->v.Constant.value);
+    }
+    else {
+        assert(node_->v.BinOp.op == Sub);
+        new = PyNumber_Subtract(left->v.Constant.value, right->v.Constant.value);
+    }
+    if (new == NULL) {
+        return 0;
+    }
+    assert(PyComplex_CheckExact(new));
+    return make_const(node_, new, ctx_);
+}
+
+static int
+astfold_pattern_keyword(keyword_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    CALL(astfold_pattern, expr_ty, node_->value);
+    return 1;
+}
+
+static int
+astfold_pattern(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    // Don't blindly optimize the pattern as an expr; it plays by its own rules!
+    // Currently, this is only used to form complex/negative numeric constants.
+    switch (node_->kind) {
+        case Attribute_kind:
+            break;
+        case BinOp_kind:
+            CALL(astfold_pattern_complex, expr_ty, node_);
+            break;
+        case Call_kind:
+            CALL_SEQ(astfold_pattern, expr, node_->v.Call.args);
+            CALL_SEQ(astfold_pattern_keyword, keyword, node_->v.Call.keywords);
+            break;
+        case Constant_kind:
+            break;
+        case Dict_kind:
+            CALL_SEQ(astfold_pattern, expr, node_->v.Dict.keys);
+            CALL_SEQ(astfold_pattern, expr, node_->v.Dict.values);
+            break;
+        // Not actually valid, but it's the compiler's job to complain:
+        case JoinedStr_kind:
+            break;
+        case List_kind:
+            CALL_SEQ(astfold_pattern, expr, node_->v.List.elts);
+            break;
+        case MatchAs_kind:
+            CALL(astfold_pattern, expr_ty, node_->v.MatchAs.pattern);
+            break;
+        case MatchOr_kind:
+            CALL_SEQ(astfold_pattern, expr, node_->v.MatchOr.patterns);
+            break;
+        case Name_kind:
+            break;
+        case Starred_kind:
+            CALL(astfold_pattern, expr_ty, node_->v.Starred.value);
+            break;
+        case Tuple_kind:
+            CALL_SEQ(astfold_pattern, expr, node_->v.Tuple.elts);
+            break;
+        case UnaryOp_kind:
+            CALL(astfold_pattern_negative, expr_ty, node_);
+            break;
+        default:
+            Py_UNREACHABLE();
+    }
+    return 1;
+}
+
+static int
+astfold_match_case(match_case_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    CALL(astfold_pattern, expr_ty, node_->pattern);
+    CALL_OPT(astfold_expr, expr_ty, node_->guard);
+    CALL_SEQ(astfold_stmt, stmt, node_->body);
+    return 1;
+}
+
 #undef CALL
 #undef CALL_OPT
 #undef CALL_SEQ

Python/ceval.c

@@ -880,6 +880,230 @@ _Py_CheckRecursiveCall(PyThreadState *tstate, const char *where)
     return 0;
 }
 
+
+// PEP 634: Structural Pattern Matching
+
+
+// Return a tuple of values corresponding to keys, with error checks for
+// duplicate/missing keys.
+static PyObject*
+match_keys(PyThreadState *tstate, PyObject *map, PyObject *keys)
+{
+    assert(PyTuple_CheckExact(keys));
+    Py_ssize_t nkeys = PyTuple_GET_SIZE(keys);
+    if (!nkeys) {
+        // No keys means no items.
+        return PyTuple_New(0);
+    }
+    PyObject *seen = NULL;
+    PyObject *dummy = NULL;
+    PyObject *values = NULL;
+    // We use the two argument form of map.get(key, default) for two reasons:
+    // - Atomically check for a key and get its value without error handling.
+    // - Don't cause key creation or resizing in dict subclasses like
+    //   collections.defaultdict that define __missing__ (or similar).
+    _Py_IDENTIFIER(get);
+    PyObject *get = _PyObject_GetAttrId(map, &PyId_get);
+    if (get == NULL) {
+        goto fail;
+    }
+    seen = PySet_New(NULL);
+    if (seen == NULL) {
+        goto fail;
+    }
+    // dummy = object()
+    dummy = _PyObject_CallNoArg((PyObject *)&PyBaseObject_Type);
+    if (dummy == NULL) {
+        goto fail;
+    }
+    values = PyList_New(0);
+    if (values == NULL) {
+        goto fail;
+    }
+    for (Py_ssize_t i = 0; i < nkeys; i++) {
+        PyObject *key = PyTuple_GET_ITEM(keys, i);
+        if (PySet_Contains(seen, key) || PySet_Add(seen, key)) {
+            if (!_PyErr_Occurred(tstate)) {
+                // Seen it before!
+                _PyErr_Format(tstate, PyExc_ValueError,
+                              "mapping pattern checks duplicate key (%R)", key);
+            }
+            goto fail;
+        }
+        PyObject *value = PyObject_CallFunctionObjArgs(get, key, dummy, NULL);
+        if (value == NULL) {
+            goto fail;
+        }
+        if (value == dummy) {
+            // key not in map!
+            Py_DECREF(value);
+            Py_DECREF(values);
+            // Return None:
+            Py_INCREF(Py_None);
+            values = Py_None;
+            goto done;
+        }
+        PyList_Append(values, value);
+        Py_DECREF(value);
+    }
+    Py_SETREF(values, PyList_AsTuple(values));
+    // Success:
+done:
+    Py_DECREF(get);
+    Py_DECREF(seen);
+    Py_DECREF(dummy);
+    return values;
+fail:
+    Py_XDECREF(get);
+    Py_XDECREF(seen);
+    Py_XDECREF(dummy);
+    Py_XDECREF(values);
+    return NULL;
+}
+
+// Extract a named attribute from the subject, with additional bookkeeping to
+// raise TypeErrors for repeated lookups. On failure, return NULL (with no
+// error set). Use _PyErr_Occurred(tstate) to disambiguate.
+static PyObject*
+match_class_attr(PyThreadState *tstate, PyObject *subject, PyObject *type,
+                 PyObject *name, PyObject *seen)
+{
+    assert(PyUnicode_CheckExact(name));
+    assert(PySet_CheckExact(seen));
+    if (PySet_Contains(seen, name) || PySet_Add(seen, name)) {
+        if (!_PyErr_Occurred(tstate)) {
+            // Seen it before!
+            _PyErr_Format(tstate, PyExc_TypeError,
+                          "%s() got multiple sub-patterns for attribute %R",
+                          ((PyTypeObject*)type)->tp_name, name);
+        }
+        return NULL;
+    }
+    PyObject *attr = PyObject_GetAttr(subject, name);
+    if (attr == NULL && _PyErr_ExceptionMatches(tstate, PyExc_AttributeError)) {
+        _PyErr_Clear(tstate);
+    }
+    return attr;
+}
+
+// On success (match), return a tuple of extracted attributes. On failure (no
+// match), return NULL. Use _PyErr_Occurred(tstate) to disambiguate.
+static PyObject*
+match_class(PyThreadState *tstate, PyObject *subject, PyObject *type,
+            Py_ssize_t nargs, PyObject *kwargs)
+{
+    if (!PyType_Check(type)) {
+        const char *e = "called match pattern must be a type";
+        _PyErr_Format(tstate, PyExc_TypeError, e);
+        return NULL;
+    }
+    assert(PyTuple_CheckExact(kwargs));
+    // First, an isinstance check:
+    if (PyObject_IsInstance(subject, type) <= 0) {
+        return NULL;
+    }
+    // So far so good:
+    PyObject *seen = PySet_New(NULL);
+    if (seen == NULL) {
+        return NULL;
+    }
+    PyObject *attrs = PyList_New(0);
+    if (attrs == NULL) {
+        Py_DECREF(seen);
+        return NULL;
+    }
+    // NOTE: From this point on, goto fail on failure:
+    PyObject *match_args = NULL;
+    // First, the positional subpatterns:
+    if (nargs) {
+        int match_self = 0;
+        match_args = PyObject_GetAttrString(type, "__match_args__");
+        if (match_args) {
+            if (PyList_CheckExact(match_args)) {
+                Py_SETREF(match_args, PyList_AsTuple(match_args));
+            }
+            if (match_args == NULL) {
+                goto fail;
+            }
+            if (!PyTuple_CheckExact(match_args)) {
+                const char *e = "%s.__match_args__ must be a list or tuple "
+                                "(got %s)";
+                _PyErr_Format(tstate, PyExc_TypeError, e,
+                              ((PyTypeObject *)type)->tp_name,
+                              Py_TYPE(match_args)->tp_name);
+                goto fail;
+            }
+        }
+        else if (_PyErr_ExceptionMatches(tstate, PyExc_AttributeError)) {
+            _PyErr_Clear(tstate);
+            // _Py_TPFLAGS_MATCH_SELF is only acknowledged if the type does not
+            // define __match_args__. This is natural behavior for subclasses:
+            // it's as if __match_args__ is some "magic" value that is lost as
+            // soon as they redefine it.
+            match_args = PyTuple_New(0);
+            match_self = PyType_HasFeature((PyTypeObject*)type,
+                                            _Py_TPFLAGS_MATCH_SELF);
+        }
+        else {
+            goto fail;
+        }
+        assert(PyTuple_CheckExact(match_args));
+        Py_ssize_t allowed = match_self ? 1 : PyTuple_GET_SIZE(match_args);
+        if (allowed < nargs) {
+            const char *plural = (allowed == 1) ? "" : "s";
+            _PyErr_Format(tstate, PyExc_TypeError,
+                          "%s() accepts %d positional sub-pattern%s (%d given)",
+                          ((PyTypeObject*)type)->tp_name,
+                          allowed, plural, nargs);
+            goto fail;
+        }
+        if (match_self) {
+            // Easy. Copy the subject itself, and move on to kwargs.
+            PyList_Append(attrs, subject);
+        }
+        else {
+            for (Py_ssize_t i = 0; i < nargs; i++) {
+                PyObject *name = PyTuple_GET_ITEM(match_args, i);
+                if (!PyUnicode_CheckExact(name)) {
+                    _PyErr_Format(tstate, PyExc_TypeError,
+                                  "__match_args__ elements must be strings "
+                                  "(got %s)", Py_TYPE(name)->tp_name);
+                    goto fail;
+                }
+                PyObject *attr = match_class_attr(tstate, subject, type, name,
+                                                  seen);
+                if (attr == NULL) {
+                    goto fail;
+                }
+                PyList_Append(attrs, attr);
+                Py_DECREF(attr);
+            }
+        }
+        Py_CLEAR(match_args);
+    }
+    // Finally, the keyword subpatterns:
+    for (Py_ssize_t i = 0; i < PyTuple_GET_SIZE(kwargs); i++) {
+        PyObject *name = PyTuple_GET_ITEM(kwargs, i);
+        PyObject *attr = match_class_attr(tstate, subject, type, name, seen);
+        if (attr == NULL) {
+            goto fail;
+        }
+        PyList_Append(attrs, attr);
+        Py_DECREF(attr);
+    }
+    Py_SETREF(attrs, PyList_AsTuple(attrs));
+    Py_DECREF(seen);
+    return attrs;
+fail:
+    // We really don't care whether an error was raised or not... that's our
+    // caller's problem. All we know is that the match failed.
+    Py_XDECREF(match_args);
+    Py_DECREF(seen);
+    Py_DECREF(attrs);
+    return NULL;
+}
+
+
 static int do_raise(PyThreadState *tstate, PyObject *exc, PyObject *cause);
 static int unpack_iterable(PyThreadState *, PyObject *, int, int, PyObject **);
 
@@ -3618,6 +3842,164 @@ main_loop:
 #endif
         }
 
+        case TARGET(GET_LEN): {
+            // PUSH(len(TOS))
+            Py_ssize_t len_i = PyObject_Length(TOP());
+            if (len_i < 0) {
+                goto error;
+            }
+            PyObject *len_o = PyLong_FromSsize_t(len_i);
+            if (len_o == NULL) {
+                goto error;
+            }
+            PUSH(len_o);
+            DISPATCH();
+        }
+
+        case TARGET(MATCH_CLASS): {
+            // Pop TOS. On success, set TOS to True and TOS1 to a tuple of
+            // attributes. On failure, set TOS to False.
+            PyObject *names = POP();
+            PyObject *type = TOP();
+            PyObject *subject = SECOND();
+            assert(PyTuple_CheckExact(names));
+            PyObject *attrs = match_class(tstate, subject, type, oparg, names);
+            Py_DECREF(names);
+            if (attrs) {
+                // Success!
+                assert(PyTuple_CheckExact(attrs));
+                Py_DECREF(subject);
+                SET_SECOND(attrs);
+            }
+            else if (_PyErr_Occurred(tstate)) {
+                goto error;
+            }
+            Py_DECREF(type);
+            SET_TOP(PyBool_FromLong(!!attrs));
+            DISPATCH();
+        }
+
+        case TARGET(MATCH_MAPPING): {
+            // PUSH(isinstance(TOS, _collections_abc.Mapping))
+            PyObject *subject = TOP();
+            // Fast path for dicts:
+            if (PyDict_Check(subject)) {
+                Py_INCREF(Py_True);
+                PUSH(Py_True);
+                DISPATCH();
+            }
+            // Lazily import _collections_abc.Mapping, and keep it handy on the
+            // PyInterpreterState struct (it gets cleaned up at exit):
+            PyInterpreterState *interp = PyInterpreterState_Get();
+            if (interp->map_abc == NULL) {
+                PyObject *abc = PyImport_ImportModule("_collections_abc");
+                if (abc == NULL) {
+                    goto error;
+                }
+                interp->map_abc = PyObject_GetAttrString(abc, "Mapping");
+                if (interp->map_abc == NULL) {
+                    goto error;
+                }
+            }
+            int match = PyObject_IsInstance(subject, interp->map_abc);
+            if (match < 0) {
+                goto error;
+            }
+            PUSH(PyBool_FromLong(match));
+            DISPATCH();
+        }
+
+        case TARGET(MATCH_SEQUENCE): {
+            // PUSH(not isinstance(TOS, (bytearray, bytes, str))
+            //      and isinstance(TOS, _collections_abc.Sequence))
+            PyObject *subject = TOP();
+            // Fast path for lists and tuples:
+            if (PyType_FastSubclass(Py_TYPE(subject),
+                                    Py_TPFLAGS_LIST_SUBCLASS |
+                                    Py_TPFLAGS_TUPLE_SUBCLASS))
+            {
+                Py_INCREF(Py_True);
+                PUSH(Py_True);
+                DISPATCH();
+            }
+            // Bail on some possible Sequences that we intentionally exclude:
+            if (PyType_FastSubclass(Py_TYPE(subject),
+                                    Py_TPFLAGS_BYTES_SUBCLASS |
+                                    Py_TPFLAGS_UNICODE_SUBCLASS) ||
+                PyByteArray_Check(subject))
+            {
+                Py_INCREF(Py_False);
+                PUSH(Py_False);
+                DISPATCH();
+            }
+            // Lazily import _collections_abc.Sequence, and keep it handy on the
+            // PyInterpreterState struct (it gets cleaned up at exit):
+            PyInterpreterState *interp = PyInterpreterState_Get();
+            if (interp->seq_abc == NULL) {
+                PyObject *abc = PyImport_ImportModule("_collections_abc");
+                if (abc == NULL) {
+                    goto error;
+                }
+                interp->seq_abc = PyObject_GetAttrString(abc, "Sequence");
+                if (interp->seq_abc == NULL) {
+                    goto error;
+                }
+            }
+            int match = PyObject_IsInstance(subject, interp->seq_abc);
+            if (match < 0) {
+                goto error;
+            }
+            PUSH(PyBool_FromLong(match));
+            DISPATCH();
+        }
+
+        case TARGET(MATCH_KEYS): {
+            // On successful match for all keys, PUSH(values) and PUSH(True).
+            // Otherwise, PUSH(None) and PUSH(False).
+            PyObject *keys = TOP();
+            PyObject *subject = SECOND();
+            PyObject *values_or_none = match_keys(tstate, subject, keys);
+            if (values_or_none == NULL) {
+                goto error;
+            }
+            PUSH(values_or_none);
+            if (values_or_none == Py_None) {
+                Py_INCREF(Py_False);
+                PUSH(Py_False);
+                DISPATCH();
+            }
+            assert(PyTuple_CheckExact(values_or_none));
+            Py_INCREF(Py_True);
+            PUSH(Py_True);
+            DISPATCH();
+        }
+
+        case TARGET(COPY_DICT_WITHOUT_KEYS): {
+            // rest = dict(TOS1)
+            // for key in TOS:
+            //     del rest[key]
+            // SET_TOP(rest)
+            PyObject *keys = TOP();
+            PyObject *subject = SECOND();
+            PyObject *rest = PyDict_New();
+            if (rest == NULL || PyDict_Update(rest, subject)) {
+                Py_XDECREF(rest);
+                goto error;
+            }
+            // This may seem a bit inefficient, but keys is rarely big enough to
+            // actually impact runtime.
+            assert(PyTuple_CheckExact(keys));
+            for (Py_ssize_t i = 0; i < PyTuple_GET_SIZE(keys); i++) {
+                if (PyDict_DelItem(rest, PyTuple_GET_ITEM(keys, i))) {
+                    Py_DECREF(rest);
+                    goto error;
+                }
+            }
+            Py_DECREF(keys);
+            SET_TOP(rest);
+            DISPATCH();
+        }
+
         case TARGET(GET_ITER): {
             /* before: [obj]; after [getiter(obj)] */
             PyObject *iterable = TOP();

Python/compile.c

@@ -202,6 +202,11 @@ struct compiler {
     PyArena *c_arena;            /* pointer to memory allocation arena */
 };
 
+typedef struct {
+    PyObject *stores;
+    int allow_irrefutable;
+} pattern_context;
+
 static int compiler_enter_scope(struct compiler *, identifier, int, void *, int);
 static void compiler_free(struct compiler *);
 static basicblock *compiler_new_block(struct compiler *);
@@ -210,7 +215,7 @@ static int compiler_addop(struct compiler *, int);
 static int compiler_addop_i(struct compiler *, int, Py_ssize_t);
 static int compiler_addop_j(struct compiler *, int, basicblock *);
 static int compiler_addop_j_noline(struct compiler *, int, basicblock *);
-static int compiler_error(struct compiler *, const char *);
+static int compiler_error(struct compiler *, const char *, ...);
 static int compiler_warn(struct compiler *, const char *, ...);
 static int compiler_nameop(struct compiler *, identifier, expr_context_ty);
 
@@ -248,6 +253,11 @@ static int compiler_async_comprehension_generator(
                                       int depth,
                                       expr_ty elt, expr_ty val, int type);
 
+static int compiler_pattern(struct compiler *, expr_ty, pattern_context *);
+static int compiler_match(struct compiler *, stmt_ty);
+static int compiler_pattern_subpattern(struct compiler *, expr_ty,
+                                       pattern_context *);
+
 static PyCodeObject *assemble(struct compiler *, int addNone);
 static PyObject *__doc__, *__annotations__;
 
@@ -1150,6 +1160,16 @@ stack_effect(int opcode, int oparg, int jump)
         case DICT_MERGE:
         case DICT_UPDATE:
             return -1;
+        case COPY_DICT_WITHOUT_KEYS:
+            return 0;
+        case MATCH_CLASS:
+            return -1;
+        case GET_LEN:
+        case MATCH_MAPPING:
+        case MATCH_SEQUENCE:
+            return 1;
+        case MATCH_KEYS:
+            return 2;
         default:
             return PY_INVALID_STACK_EFFECT;
     }
@@ -1580,6 +1600,11 @@ compiler_addop_j_noline(struct compiler *c, int opcode, basicblock *b)
     } \
 }
 
+#define RETURN_IF_FALSE(X)  \
+    if (!(X)) {             \
+        return 0;           \
+    }
+
 /* Search if variable annotations are present statically in a block. */
 
 static int
@@ -3414,6 +3439,8 @@ compiler_visit_stmt(struct compiler *c, stmt_ty s)
         return compiler_while(c, s);
     case If_kind:
         return compiler_if(c, s);
+    case Match_kind:
+        return compiler_match(c, s);
     case Raise_kind:
         n = 0;
         if (s->v.Raise.exc) {
@@ -3758,12 +3785,11 @@ starunpack_helper(struct compiler *c, asdl_expr_seq *elts, int pushed,
 }
 
 static int
-assignment_helper(struct compiler *c, asdl_expr_seq *elts)
+unpack_helper(struct compiler *c, asdl_expr_seq *elts)
 {
     Py_ssize_t n = asdl_seq_LEN(elts);
-    Py_ssize_t i;
     int seen_star = 0;
-    for (i = 0; i < n; i++) {
+    for (Py_ssize_t i = 0; i < n; i++) {
         expr_ty elt = asdl_seq_GET(elts, i);
         if (elt->kind == Starred_kind && !seen_star) {
             if ((i >= (1 << 8)) ||
@@ -3782,7 +3808,15 @@ assignment_helper(struct compiler *c, asdl_expr_seq *elts)
     if (!seen_star) {
         ADDOP_I(c, UNPACK_SEQUENCE, n);
     }
-    for (i = 0; i < n; i++) {
+    return 1;
+}
+
+static int
+assignment_helper(struct compiler *c, asdl_expr_seq *elts)
+{
+    Py_ssize_t n = asdl_seq_LEN(elts);
+    RETURN_IF_FALSE(unpack_helper(c, elts));
+    for (Py_ssize_t i = 0; i < n; i++) {
         expr_ty elt = asdl_seq_GET(elts, i);
         VISIT(c, expr, elt->kind != Starred_kind ? elt : elt->v.Starred.value);
     }
@@ -4132,13 +4166,8 @@ validate_keywords(struct compiler *c, asdl_keyword_seq *keywords)
         for (Py_ssize_t j = i + 1; j < nkeywords; j++) {
             keyword_ty other = ((keyword_ty)asdl_seq_GET(keywords, j));
             if (other->arg && !PyUnicode_Compare(key->arg, other->arg)) {
-                PyObject *msg = PyUnicode_FromFormat("keyword argument repeated: %U", key->arg);
-                if (msg == NULL) {
-                    return -1;
-                }
                 c->u->u_col_offset = other->col_offset;
-                compiler_error(c, PyUnicode_AsUTF8(msg));
+                compiler_error(c, "keyword argument repeated: %U", key->arg);
-                Py_DECREF(msg);
                 return -1;
             }
         }
@@ -5119,6 +5148,10 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
         return compiler_list(c, e);
     case Tuple_kind:
         return compiler_tuple(c, e);
+    case MatchAs_kind:
+    case MatchOr_kind:
+        // Can only occur in patterns, which are handled elsewhere.
+        Py_UNREACHABLE();
     }
     return 1;
 }
@@ -5305,28 +5338,34 @@ compiler_annassign(struct compiler *c, stmt_ty s)
 */
 
 static int
-compiler_error(struct compiler *c, const char *errstr)
+compiler_error(struct compiler *c, const char *format, ...)
 {
-    PyObject *loc;
+    va_list vargs;
-    PyObject *u = NULL, *v = NULL;
+#ifdef HAVE_STDARG_PROTOTYPES
-
+    va_start(vargs, format);
-    loc = PyErr_ProgramTextObject(c->c_filename, c->u->u_lineno);
+#else
-    if (!loc) {
+    va_start(vargs);
+#endif
+    PyObject *msg = PyUnicode_FromFormatV(format, vargs);
+    va_end(vargs);
+    if (msg == NULL) {
+        return 0;
+    }
+    PyObject *loc = PyErr_ProgramTextObject(c->c_filename, c->u->u_lineno);
+    if (loc == NULL) {
         Py_INCREF(Py_None);
         loc = Py_None;
     }
-    u = Py_BuildValue("(OiiO)", c->c_filename, c->u->u_lineno,
+    PyObject *args = Py_BuildValue("O(OiiO)", msg, c->c_filename,
-                      c->u->u_col_offset + 1, loc);
+                                   c->u->u_lineno, c->u->u_col_offset + 1, loc);
-    if (!u)
+    Py_DECREF(msg);
+    if (args == NULL) {
         goto exit;
-    v = Py_BuildValue("(zO)", errstr, u);
+    }
-    if (!v)
+    PyErr_SetObject(PyExc_SyntaxError, args);
-        goto exit;
-    PyErr_SetObject(PyExc_SyntaxError, v);
  exit:
     Py_DECREF(loc);
-    Py_XDECREF(u);
+    Py_XDECREF(args);
-    Py_XDECREF(v);
     return 0;
 }
 
@@ -5421,6 +5460,654 @@ compiler_slice(struct compiler *c, expr_ty s)
     return 1;
 }
 
+
+// PEP 634: Structural Pattern Matching
+
+// To keep things simple, all compiler_pattern_* routines follow the convention
+// of replacing TOS (the subject for the given pattern) with either True (match)
+// or False (no match). We do this even for irrefutable patterns; the idea is
+// that it's much easier to smooth out any redundant pushing, popping, and
+// jumping in the peephole optimizer than to detect or predict it here.
+
+
+#define WILDCARD_CHECK(N) \
+    ((N)->kind == Name_kind && \
+    _PyUnicode_EqualToASCIIString((N)->v.Name.id, "_"))
+
+
+static int
+pattern_helper_store_name(struct compiler *c, identifier n, pattern_context *pc)
+{
+    assert(!_PyUnicode_EqualToASCIIString(n, "_"));
+    // Can't assign to the same name twice:
+    if (pc->stores == NULL) {
+        RETURN_IF_FALSE(pc->stores = PySet_New(NULL));
+    }
+    else {
+        int duplicate = PySet_Contains(pc->stores, n);
+        if (duplicate < 0) {
+            return 0;
+        }
+        if (duplicate) {
+            const char *e = "multiple assignments to name %R in pattern";
+            return compiler_error(c, e, n);
+        }
+    }
+    RETURN_IF_FALSE(!PySet_Add(pc->stores, n));
+    RETURN_IF_FALSE(compiler_nameop(c, n, Store));
+    return 1;
+}
+
+
+static int
+pattern_helper_sequence_unpack(struct compiler *c, asdl_expr_seq *values,
+                               Py_ssize_t star, pattern_context *pc)
+{
+    RETURN_IF_FALSE(unpack_helper(c, values));
+    // We've now got a bunch of new subjects on the stack. If any of them fail
+    // to match, we need to pop everything else off, then finally push False.
+    // fails is an array of blocks that correspond to the necessary amount of
+    // popping for each element:
+    basicblock **fails;
+    Py_ssize_t size = asdl_seq_LEN(values);
+    fails = (basicblock **)PyObject_Malloc(sizeof(basicblock*) * size);
+    if (fails == NULL) {
+        PyErr_NoMemory();
+        return 0;
+    }
+    // NOTE: Can't use our nice returning macros anymore: they'll leak memory!
+    // goto error on error.
+    for (Py_ssize_t i = 0; i < size; i++) {
+        fails[i] = compiler_new_block(c);
+        if (fails[i] == NULL) {
+            goto error;
+        }
+    }
+    for (Py_ssize_t i = 0; i < size; i++) {
+        expr_ty value = asdl_seq_GET(values, i);
+        if (i == star) {
+            assert(value->kind == Starred_kind);
+            value = value->v.Starred.value;
+        }
+        if (!compiler_pattern_subpattern(c, value, pc) ||
+            !compiler_addop_j(c, POP_JUMP_IF_FALSE, fails[i]) ||
+            compiler_next_block(c) == NULL)
+        {
+            goto error;
+        }
+    }
+    // Success!
+    basicblock *end = compiler_new_block(c);
+    if (end == NULL ||
+        !compiler_addop_load_const(c, Py_True) ||
+        !compiler_addop_j(c, JUMP_FORWARD, end))
+    {
+        goto error;
+    }
+    // This is where we handle failed sub-patterns. For a sequence pattern like
+    // [a, b, c, d], this will look like:
+    // fails[0]: POP_TOP
+    // fails[1]: POP_TOP
+    // fails[2]: POP_TOP
+    // fails[3]: LOAD_CONST False
+    for (Py_ssize_t i = 0; i < size - 1; i++) {
+        compiler_use_next_block(c, fails[i]);
+        if (!compiler_addop(c, POP_TOP)) {
+            goto error;
+        }
+    }
+    compiler_use_next_block(c, fails[size - 1]);
+    if (!compiler_addop_load_const(c, Py_False)) {
+        goto error;
+    }
+    compiler_use_next_block(c, end);
+    PyObject_Free(fails);
+    return 1;
+error:
+    PyObject_Free(fails);
+    return 0;
+}
+
+// Like pattern_helper_sequence_unpack, but uses BINARY_SUBSCR instead of
+// UNPACK_SEQUENCE / UNPACK_EX. This is more efficient for patterns with a
+// starred wildcard like [first, *_] / [first, *_, last] / [*_, last] / etc.
+static int
+pattern_helper_sequence_subscr(struct compiler *c, asdl_expr_seq *values,
+                               Py_ssize_t star, pattern_context *pc)
+{
+    basicblock *end, *fail_pop_1;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
+    Py_ssize_t size = asdl_seq_LEN(values);
+    for (Py_ssize_t i = 0; i < size; i++) {
+        expr_ty value = asdl_seq_GET(values, i);
+        if (WILDCARD_CHECK(value)) {
+            continue;
+        }
+        if (i == star) {
+            assert(value->kind == Starred_kind);
+            assert(WILDCARD_CHECK(value->v.Starred.value));
+            continue;
+        }
+        ADDOP(c, DUP_TOP);
+        if (i < star) {
+            ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
+        }
+        else {
+            // The subject may not support negative indexing! Compute a
+            // nonnegative index:
+            ADDOP(c, GET_LEN);
+            ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size - i));
+            ADDOP(c, BINARY_SUBTRACT);
+        }
+        ADDOP(c, BINARY_SUBSCR);
+        RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+        NEXT_BLOCK(c);
+    }
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_True);
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    compiler_use_next_block(c, fail_pop_1);
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_False);
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+// Like compiler_pattern, but turn off checks for irrefutability.
+static int
+compiler_pattern_subpattern(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    int allow_irrefutable = pc->allow_irrefutable;
+    pc->allow_irrefutable = 1;
+    RETURN_IF_FALSE(compiler_pattern(c, p, pc));
+    pc->allow_irrefutable = allow_irrefutable;
+    return 1;
+}
+
+
+static int
+compiler_pattern_as(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == MatchAs_kind);
+    basicblock *end, *fail_pop_1;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
+    // Need to make a copy for (possibly) storing later:
+    ADDOP(c, DUP_TOP);
+    RETURN_IF_FALSE(compiler_pattern(c, p->v.MatchAs.pattern, pc));
+    ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+    NEXT_BLOCK(c);
+    RETURN_IF_FALSE(pattern_helper_store_name(c, p->v.MatchAs.name, pc));
+    ADDOP_LOAD_CONST(c, Py_True);
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    compiler_use_next_block(c, fail_pop_1);
+    // Need to pop that unused copy from before:
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_False);
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+static int
+compiler_pattern_capture(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == Name_kind);
+    assert(p->v.Name.ctx == Store);
+    assert(!WILDCARD_CHECK(p));
+    if (!pc->allow_irrefutable) {
+        // Whoops, can't have a name capture here!
+        const char *e = "name capture %R makes remaining patterns unreachable";
+        return compiler_error(c, e, p->v.Name.id);
+    }
+    RETURN_IF_FALSE(pattern_helper_store_name(c, p->v.Name.id, pc));
+    ADDOP_LOAD_CONST(c, Py_True);
+    return 1;
+}
+
+
+static int
+compiler_pattern_class(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    asdl_expr_seq *args = p->v.Call.args;
+    asdl_keyword_seq *kwargs = p->v.Call.keywords;
+    Py_ssize_t nargs = asdl_seq_LEN(args);
+    Py_ssize_t nkwargs = asdl_seq_LEN(kwargs);
+    if (INT_MAX < nargs || INT_MAX < nargs + nkwargs - 1) {
+        const char *e = "too many sub-patterns in class pattern %R";
+        return compiler_error(c, e, p->v.Call.func);
+    }
+    RETURN_IF_FALSE(!validate_keywords(c, kwargs));
+    basicblock *end, *fail_pop_1;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
+    VISIT(c, expr, p->v.Call.func);
+    PyObject *kwnames;
+    RETURN_IF_FALSE(kwnames = PyTuple_New(nkwargs));
+    Py_ssize_t i;
+    for (i = 0; i < nkwargs; i++) {
+        PyObject *name = ((keyword_ty) asdl_seq_GET(kwargs, i))->arg;
+        Py_INCREF(name);
+        PyTuple_SET_ITEM(kwnames, i, name);
+    }
+    ADDOP_LOAD_CONST_NEW(c, kwnames);
+    ADDOP_I(c, MATCH_CLASS, nargs);
+    ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+    NEXT_BLOCK(c);
+    // TOS is now a tuple of (nargs + nkwargs) attributes.
+    for (i = 0; i < nargs + nkwargs; i++) {
+        expr_ty arg;
+        if (i < nargs) {
+            // Positional:
+            arg = asdl_seq_GET(args, i);
+        }
+        else {
+            // Keyword:
+            arg = ((keyword_ty) asdl_seq_GET(kwargs, i - nargs))->value;
+        }
+        if (WILDCARD_CHECK(arg)) {
+            continue;
+        }
+        // Get the i-th attribute, and match it against the i-th pattern:
+        ADDOP(c, DUP_TOP);
+        ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
+        ADDOP(c, BINARY_SUBSCR);
+        RETURN_IF_FALSE(compiler_pattern_subpattern(c, arg, pc));
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+        NEXT_BLOCK(c);
+    }
+    // Success! Pop the tuple of attributes:
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_True);
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    compiler_use_next_block(c, fail_pop_1);
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_False);
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+static int
+compiler_pattern_literal(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == Constant_kind);
+    PyObject *v = p->v.Constant.value;
+    ADDOP_LOAD_CONST(c, v);
+    // Literal True, False, and None are compared by identity. All others use
+    // equality:
+    ADDOP_COMPARE(c, (v == Py_None || PyBool_Check(v)) ? Is : Eq);
+    return 1;
+}
+
+
+static int
+compiler_pattern_mapping(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    basicblock *end, *fail_pop_1, *fail_pop_3;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_3 = compiler_new_block(c));
+    asdl_expr_seq *keys = p->v.Dict.keys;
+    asdl_expr_seq *values = p->v.Dict.values;
+    Py_ssize_t size = asdl_seq_LEN(values);
+    // A starred pattern will be a keyless value. It is guranteed to be last:
+    int star = size ? !asdl_seq_GET(keys, size - 1) : 0;
+    ADDOP(c, MATCH_MAPPING);
+    ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+    NEXT_BLOCK(c);
+    if (!size) {
+        // If the pattern is just "{}", we're done!
+        ADDOP(c, POP_TOP);
+        ADDOP_LOAD_CONST(c, Py_True);
+        ADDOP_JUMP(c, JUMP_FORWARD, end);
+        compiler_use_next_block(c, fail_pop_1);
+        ADDOP(c, POP_TOP);
+        ADDOP_LOAD_CONST(c, Py_False);
+        compiler_use_next_block(c, end);
+        return 1;
+    }
+    if (size - star) {
+        // If the pattern has any keys in it, perform a length check:
+        ADDOP(c, GET_LEN);
+        ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size - star));
+        ADDOP_COMPARE(c, GtE);
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+        NEXT_BLOCK(c);
+    }
+    if (INT_MAX < size - star - 1) {
+        return compiler_error(c, "too many sub-patterns in mapping pattern");
+    }
+    // Collect all of the keys into a tuple for MATCH_KEYS and
+    // COPY_DICT_WITHOUT_KEYS. They can either be dotted names or literals:
+    for (Py_ssize_t i = 0; i < size - star; i++) {
+        expr_ty key = asdl_seq_GET(keys, i);
+        if (key == NULL) {
+            const char *e = "can't use starred name here "
+                            "(consider moving to end)";
+            return compiler_error(c, e);
+        }
+        VISIT(c, expr, key);
+    }
+    ADDOP_I(c, BUILD_TUPLE, size - star);
+    ADDOP(c, MATCH_KEYS);
+    ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
+    NEXT_BLOCK(c);
+    // So far so good. There's now a tuple of values on the stack to match
+    // sub-patterns against:
+    for (Py_ssize_t i = 0; i < size - star; i++) {
+        expr_ty value = asdl_seq_GET(values, i);
+        if (WILDCARD_CHECK(value)) {
+            continue;
+        }
+        ADDOP(c, DUP_TOP);
+        ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(i));
+        ADDOP(c, BINARY_SUBSCR);
+        RETURN_IF_FALSE(compiler_pattern_subpattern(c, value, pc));
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_3);
+        NEXT_BLOCK(c);
+    }
+    // If we get this far, it's a match! We're done with that tuple of values.
+    ADDOP(c, POP_TOP);
+    if (star) {
+        // If we had a starred name, bind a dict of remaining items to it:
+        ADDOP(c, COPY_DICT_WITHOUT_KEYS);
+        PyObject *id = asdl_seq_GET(values, size - 1)->v.Name.id;
+        RETURN_IF_FALSE(pattern_helper_store_name(c, id, pc));
+    }
+    else {
+        // Otherwise, we don't care about this tuple of keys anymore:
+        ADDOP(c, POP_TOP);
+    }
+    // Pop the subject:
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_True);
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    // The top two items are a tuple of values or None, followed by a tuple of
+    // keys. Pop them both:
+    compiler_use_next_block(c, fail_pop_3);
+    ADDOP(c, POP_TOP);
+    ADDOP(c, POP_TOP);
+    compiler_use_next_block(c, fail_pop_1);
+    // Pop the subject:
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_False);
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+static int
+compiler_pattern_or(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == MatchOr_kind);
+    // control is the set of names bound by the first alternative. If all of the
+    // others bind the same names (they should), then this becomes pc->stores.
+    PyObject *control = NULL;
+    basicblock *end, *pass_pop_1;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(pass_pop_1 = compiler_new_block(c));
+    Py_ssize_t size = asdl_seq_LEN(p->v.MatchOr.patterns);
+    assert(size > 1);
+    // We're going to be messing with pc. Keep the original info handy:
+    PyObject *stores_init = pc->stores;
+    int allow_irrefutable = pc->allow_irrefutable;
+    for (Py_ssize_t i = 0; i < size; i++) {
+        // NOTE: Can't use our nice returning macros in here: they'll leak sets!
+        expr_ty alt = asdl_seq_GET(p->v.MatchOr.patterns, i);
+        pc->stores = PySet_New(stores_init);
+        // An irrefutable sub-pattern must be last, if it is allowed at all:
+        int is_last = i == size - 1;
+        pc->allow_irrefutable = allow_irrefutable && is_last;
+        SET_LOC(c, alt);
+        if (pc->stores == NULL ||
+            // Only copy the subject if we're *not* on the last alternative:
+            (!is_last && !compiler_addop(c, DUP_TOP)) ||
+            !compiler_pattern(c, alt, pc) ||
+            // Only jump if we're *not* on the last alternative:
+            (!is_last && !compiler_addop_j(c, POP_JUMP_IF_TRUE, pass_pop_1)) ||
+            !compiler_next_block(c))
+        {
+            goto fail;
+        }
+        if (!i) {
+            // If this is the first alternative, save its stores as a "control"
+            // for the others (they can't bind a different set of names):
+            control = pc->stores;
+            continue;
+        }
+        if (PySet_GET_SIZE(pc->stores) || PySet_GET_SIZE(control)) {
+            // Otherwise, check to see if we differ from the control set:
+            PyObject *diff = PyNumber_InPlaceXor(pc->stores, control);
+            if (diff == NULL) {
+                goto fail;
+            }
+            if (PySet_GET_SIZE(diff)) {
+                // The names differ! Raise.
+                Py_DECREF(diff);
+                compiler_error(c, "alternative patterns bind different names");
+                goto fail;
+            }
+            Py_DECREF(diff);
+        }
+        Py_DECREF(pc->stores);
+    }
+    Py_XDECREF(stores_init);
+    // Update pc->stores and restore pc->allow_irrefutable:
+    pc->stores = control;
+    pc->allow_irrefutable = allow_irrefutable;
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    compiler_use_next_block(c, pass_pop_1);
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_True);
+    compiler_use_next_block(c, end);
+    return 1;
+fail:
+    Py_XDECREF(stores_init);
+    Py_XDECREF(control);
+    return 0;
+}
+
+
+static int
+compiler_pattern_sequence(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == List_kind || p->kind == Tuple_kind);
+    asdl_expr_seq *values = (p->kind == Tuple_kind) ? p->v.Tuple.elts
+                                                    : p->v.List.elts;
+    Py_ssize_t size = asdl_seq_LEN(values);
+    Py_ssize_t star = -1;
+    int only_wildcard = 1;
+    int star_wildcard = 0;
+    // Find a starred name, if it exists. There may be at most one:
+    for (Py_ssize_t i = 0; i < size; i++) {
+        expr_ty value = asdl_seq_GET(values, i);
+        if (value->kind == Starred_kind) {
+            value = value->v.Starred.value;
+            if (star >= 0) {
+                const char *e = "multiple starred names in sequence pattern";
+                return compiler_error(c, e);
+            }
+            star_wildcard = WILDCARD_CHECK(value);
+            star = i;
+        }
+        only_wildcard &= WILDCARD_CHECK(value);
+    }
+    basicblock *end, *fail_pop_1;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    RETURN_IF_FALSE(fail_pop_1 = compiler_new_block(c));
+    ADDOP(c, MATCH_SEQUENCE);
+    ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+    NEXT_BLOCK(c);
+    if (star < 0) {
+        // No star: len(subject) == size
+        ADDOP(c, GET_LEN);
+        ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size));
+        ADDOP_COMPARE(c, Eq);
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+        NEXT_BLOCK(c);
+    }
+    else if (size > 1) {
+        // Star: len(subject) >= size - 1
+        ADDOP(c, GET_LEN);
+        ADDOP_LOAD_CONST_NEW(c, PyLong_FromSsize_t(size - 1));
+        ADDOP_COMPARE(c, GtE);
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, fail_pop_1);
+        NEXT_BLOCK(c);
+    }
+    if (only_wildcard) {
+        // Patterns like: [] / [_] / [_, _] / [*_] / [_, *_] / [_, _, *_] / etc.
+        ADDOP(c, POP_TOP);
+        ADDOP_LOAD_CONST(c, Py_True);
+    }
+    else if (star_wildcard) {
+        RETURN_IF_FALSE(pattern_helper_sequence_subscr(c, values, star, pc));
+    }
+    else {
+        RETURN_IF_FALSE(pattern_helper_sequence_unpack(c, values, star, pc));
+    }
+    ADDOP_JUMP(c, JUMP_FORWARD, end);
+    compiler_use_next_block(c, fail_pop_1);
+    ADDOP(c, POP_TOP)
+    ADDOP_LOAD_CONST(c, Py_False);
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+static int
+compiler_pattern_value(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == Attribute_kind);
+    assert(p->v.Attribute.ctx == Load);
+    VISIT(c, expr, p);
+    ADDOP_COMPARE(c, Eq);
+    return 1;
+}
+
+
+static int
+compiler_pattern_wildcard(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    assert(p->kind == Name_kind);
+    assert(p->v.Name.ctx == Store);
+    assert(WILDCARD_CHECK(p));
+    if (!pc->allow_irrefutable) {
+        // Whoops, can't have a wildcard here!
+        const char *e = "wildcard makes remaining patterns unreachable";
+        return compiler_error(c, e);
+    }
+    ADDOP(c, POP_TOP);
+    ADDOP_LOAD_CONST(c, Py_True);
+    return 1;
+}
+
+
+static int
+compiler_pattern(struct compiler *c, expr_ty p, pattern_context *pc)
+{
+    SET_LOC(c, p);
+    switch (p->kind) {
+        case Attribute_kind:
+            return compiler_pattern_value(c, p, pc);
+        case BinOp_kind:
+            // Because we allow "2+2j", things like "2+2" make it this far:
+            return compiler_error(c, "patterns cannot include operators");
+        case Call_kind:
+            return compiler_pattern_class(c, p, pc);
+        case Constant_kind:
+            return compiler_pattern_literal(c, p, pc);
+        case Dict_kind:
+            return compiler_pattern_mapping(c, p, pc);
+        case JoinedStr_kind:
+            // Because we allow strings, f-strings make it this far:
+            return compiler_error(c, "patterns cannot include f-strings");
+        case List_kind:
+        case Tuple_kind:
+            return compiler_pattern_sequence(c, p, pc);
+        case MatchAs_kind:
+            return compiler_pattern_as(c, p, pc);
+        case MatchOr_kind:
+            return compiler_pattern_or(c, p, pc);
+        case Name_kind:
+            if (WILDCARD_CHECK(p)) {
+                return compiler_pattern_wildcard(c, p, pc);
+            }
+            return compiler_pattern_capture(c, p, pc);
+        default:
+            Py_UNREACHABLE();
+    }
+}
+
+
+static int
+compiler_match(struct compiler *c, stmt_ty s)
+{
+    VISIT(c, expr, s->v.Match.subject);
+    basicblock *next, *end;
+    RETURN_IF_FALSE(end = compiler_new_block(c));
+    Py_ssize_t cases = asdl_seq_LEN(s->v.Match.cases);
+    assert(cases);
+    pattern_context pc;
+    // We use pc.stores to track:
+    // - Repeated name assignments in the same pattern.
+    // - Different name assignments in alternatives.
+    // It's a set of names, but we don't create it until it's needed:
+    pc.stores = NULL;
+    match_case_ty m = asdl_seq_GET(s->v.Match.cases, cases - 1);
+    int has_default = WILDCARD_CHECK(m->pattern) && 1 < cases;
+    for (Py_ssize_t i = 0; i < cases - has_default; i++) {
+        m = asdl_seq_GET(s->v.Match.cases, i);
+        SET_LOC(c, m->pattern);
+        RETURN_IF_FALSE(next = compiler_new_block(c));
+        // If pc.allow_irrefutable is 0, any name captures against our subject
+        // will raise. Irrefutable cases must be either guarded, last, or both:
+        pc.allow_irrefutable = m->guard != NULL || i == cases - 1;
+        // Only copy the subject if we're *not* on the last case:
+        if (i != cases - has_default - 1) {
+            ADDOP(c, DUP_TOP);
+        }
+        int result = compiler_pattern(c, m->pattern, &pc);
+        Py_CLEAR(pc.stores);
+        RETURN_IF_FALSE(result);
+        ADDOP_JUMP(c, POP_JUMP_IF_FALSE, next);
+        NEXT_BLOCK(c);
+        if (m->guard) {
+            RETURN_IF_FALSE(compiler_jump_if(c, m->guard, next, 0));
+        }
+        // Success! Pop the subject off, we're done with it:
+        if (i != cases - has_default - 1) {
+            ADDOP(c, POP_TOP);
+        }
+        VISIT_SEQ(c, stmt, m->body);
+        ADDOP_JUMP(c, JUMP_FORWARD, end);
+        compiler_use_next_block(c, next);
+    }
+    if (has_default) {
+        if (cases == 1) {
+            // No matches. Done with the subject:
+            ADDOP(c, POP_TOP);
+        }
+        // A trailing "case _" is common, and lets us save a bit of redundant
+        // pushing and popping in the loop above:
+        m = asdl_seq_GET(s->v.Match.cases, cases - 1);
+        SET_LOC(c, m->pattern);
+        if (m->guard) {
+            RETURN_IF_FALSE(compiler_jump_if(c, m->guard, end, 0));
+        }
+        VISIT_SEQ(c, stmt, m->body);
+    }
+    compiler_use_next_block(c, end);
+    return 1;
+}
+
+
+#undef WILDCARD_CHECK
+
+
 /* End of the compiler section, beginning of the assembler section */
 
 /* do depth-first search of basic block graph, starting with block.

Python/importlib_external.h

@@ -315,7 +315,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,115,38,0,0,0,16,5,6,1,22,1,4,255,
     2,2,14,3,24,1,16,128,18,1,12,1,2,1,12,1,
     2,3,12,254,2,1,2,1,2,254,2,253,255,128,114,84,
-    0,0,0,105,105,13,0,0,114,45,0,0,0,114,33,0,
+    0,0,0,105,106,13,0,0,114,45,0,0,0,114,33,0,
     0,0,115,2,0,0,0,13,10,90,11,95,95,112,121,99,
     97,99,104,101,95,95,122,4,111,112,116,45,122,3,46,112,
     121,122,4,46,112,121,119,122,4,46,112,121,99,41,1,218,
@@ -429,7 +429,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     90,15,97,108,109,111,115,116,95,102,105,108,101,110,97,109,
     101,218,8,102,105,108,101,110,97,109,101,114,7,0,0,0,
     114,7,0,0,0,114,8,0,0,0,218,17,99,97,99,104,
-    101,95,102,114,111,109,95,115,111,117,114,99,101,85,1,0,
+    101,95,102,114,111,109,95,115,111,117,114,99,101,86,1,0,
     0,115,74,0,0,0,8,18,6,1,2,1,4,255,8,2,
     4,1,8,1,12,1,10,1,12,1,16,1,8,1,8,1,
     8,1,24,1,8,1,12,1,6,1,8,2,8,1,8,1,
@@ -510,7 +510,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,90,9,111,112,116,95,108,101,118,101,108,90,13,98,
     97,115,101,95,102,105,108,101,110,97,109,101,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,218,17,115,111,117,
-    114,99,101,95,102,114,111,109,95,99,97,99,104,101,156,1,
+    114,99,101,95,102,114,111,109,95,99,97,99,104,101,157,1,
     0,0,115,62,0,0,0,12,9,8,1,10,1,12,1,4,
     1,10,1,12,1,14,1,16,1,4,1,4,1,12,1,8,
     1,8,1,2,1,8,255,10,2,8,1,14,1,10,1,16,
@@ -546,7 +546,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     120,116,101,110,115,105,111,110,218,11,115,111,117,114,99,101,
     95,112,97,116,104,114,7,0,0,0,114,7,0,0,0,114,
     8,0,0,0,218,15,95,103,101,116,95,115,111,117,114,99,
-    101,102,105,108,101,196,1,0,0,115,24,0,0,0,12,7,
+    101,102,105,108,101,197,1,0,0,115,24,0,0,0,12,7,
     4,1,16,1,24,1,4,1,2,1,12,1,16,1,14,1,
     16,1,2,254,255,128,114,120,0,0,0,99,1,0,0,0,
     0,0,0,0,0,0,0,0,1,0,0,0,8,0,0,0,
@@ -559,7 +559,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     112,108,101,114,113,0,0,0,114,109,0,0,0,114,95,0,
     0,0,114,101,0,0,0,41,1,114,108,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,218,11,95,
-    103,101,116,95,99,97,99,104,101,100,215,1,0,0,115,20,
+    103,101,116,95,99,97,99,104,101,100,216,1,0,0,115,20,
     0,0,0,14,1,2,1,10,1,12,1,6,1,14,1,4,
     1,4,2,2,251,255,128,114,124,0,0,0,99,1,0,0,
     0,0,0,0,0,0,0,0,0,2,0,0,0,8,0,0,
@@ -574,7 +574,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,114,65,0,0,0,114,64,0,0,0,41,2,114,
     58,0,0,0,114,66,0,0,0,114,7,0,0,0,114,7,
     0,0,0,114,8,0,0,0,218,10,95,99,97,108,99,95,
-    109,111,100,101,227,1,0,0,115,16,0,0,0,2,2,14,
+    109,111,100,101,228,1,0,0,115,16,0,0,0,2,2,14,
     1,12,1,6,1,8,3,4,1,2,251,255,128,114,126,0,
     0,0,99,1,0,0,0,0,0,0,0,0,0,0,0,3,
     0,0,0,4,0,0,0,3,0,0,0,115,52,0,0,0,
@@ -611,7 +611,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     108,102,114,128,0,0,0,218,4,97,114,103,115,218,6,107,
     119,97,114,103,115,169,1,218,6,109,101,116,104,111,100,114,
     7,0,0,0,114,8,0,0,0,218,19,95,99,104,101,99,
-    107,95,110,97,109,101,95,119,114,97,112,112,101,114,247,1,
+    107,95,110,97,109,101,95,119,114,97,112,112,101,114,248,1,
     0,0,115,20,0,0,0,8,1,8,1,10,1,4,1,8,
     1,2,255,2,1,6,255,24,2,255,128,122,40,95,99,104,
     101,99,107,95,110,97,109,101,46,60,108,111,99,97,108,115,
@@ -630,14 +630,14 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     99,116,95,95,218,6,117,112,100,97,116,101,41,3,90,3,
     110,101,119,90,3,111,108,100,114,82,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,5,95,119,
-    114,97,112,4,2,0,0,115,12,0,0,0,8,1,10,1,
+    114,97,112,5,2,0,0,115,12,0,0,0,8,1,10,1,
     18,1,2,128,18,1,255,128,122,26,95,99,104,101,99,107,
     95,110,97,109,101,46,60,108,111,99,97,108,115,62,46,95,
     119,114,97,112,41,1,78,41,2,218,10,95,98,111,111,116,
     115,116,114,97,112,114,145,0,0,0,41,3,114,134,0,0,
     0,114,135,0,0,0,114,145,0,0,0,114,7,0,0,0,
     114,133,0,0,0,114,8,0,0,0,218,11,95,99,104,101,
-    99,107,95,110,97,109,101,239,1,0,0,115,14,0,0,0,
+    99,107,95,110,97,109,101,240,1,0,0,115,14,0,0,0,
     14,8,8,10,8,1,8,2,10,6,4,1,255,128,114,147,
     0,0,0,99,2,0,0,0,0,0,0,0,0,0,0,0,
     5,0,0,0,6,0,0,0,67,0,0,0,115,60,0,0,
@@ -665,7 +665,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     97,109,101,218,6,108,111,97,100,101,114,218,8,112,111,114,
     116,105,111,110,115,218,3,109,115,103,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,17,95,102,105,110,100,
-    95,109,111,100,117,108,101,95,115,104,105,109,14,2,0,0,
+    95,109,111,100,117,108,101,95,115,104,105,109,15,2,0,0,
     115,12,0,0,0,14,10,16,1,4,1,22,1,4,1,255,
     128,114,154,0,0,0,99,3,0,0,0,0,0,0,0,0,
     0,0,0,6,0,0,0,4,0,0,0,67,0,0,0,115,
@@ -733,7 +733,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     115,90,5,109,97,103,105,99,114,105,0,0,0,114,17,0,
     0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,0,
     0,218,13,95,99,108,97,115,115,105,102,121,95,112,121,99,
-    31,2,0,0,115,30,0,0,0,12,16,8,1,16,1,12,
+    32,2,0,0,115,30,0,0,0,12,16,8,1,16,1,12,
     1,16,1,12,1,10,1,12,1,8,1,16,1,8,2,16,
     1,16,1,4,1,255,128,114,163,0,0,0,99,5,0,0,
     0,0,0,0,0,0,0,0,0,6,0,0,0,4,0,0,
@@ -788,7 +788,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,114,162,0,0,0,114,105,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,23,95,118,
     97,108,105,100,97,116,101,95,116,105,109,101,115,116,97,109,
-    112,95,112,121,99,64,2,0,0,115,20,0,0,0,24,19,
+    112,95,112,121,99,65,2,0,0,115,20,0,0,0,24,19,
     10,1,12,1,16,1,8,1,22,1,2,255,22,2,8,254,
     255,128,114,167,0,0,0,99,4,0,0,0,0,0,0,0,
     0,0,0,0,4,0,0,0,4,0,0,0,67,0,0,0,
@@ -834,7 +834,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,218,11,115,111,117,114,99,101,95,104,97,115,104,114,
     128,0,0,0,114,162,0,0,0,114,7,0,0,0,114,7,
     0,0,0,114,8,0,0,0,218,18,95,118,97,108,105,100,
-    97,116,101,95,104,97,115,104,95,112,121,99,92,2,0,0,
+    97,116,101,95,104,97,115,104,95,112,121,99,93,2,0,0,
     115,16,0,0,0,16,17,2,1,8,1,4,255,2,2,6,
     254,4,255,255,128,114,169,0,0,0,99,4,0,0,0,0,
     0,0,0,0,0,0,0,5,0,0,0,5,0,0,0,67,
@@ -858,7 +858,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,42,0,0,0,114,128,0,0,0,114,118,0,0,0,114,
     119,0,0,0,218,4,99,111,100,101,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,17,95,99,111,109,112,
-    105,108,101,95,98,121,116,101,99,111,100,101,116,2,0,0,
+    105,108,101,95,98,121,116,101,99,111,100,101,117,2,0,0,
     115,20,0,0,0,10,2,10,1,12,1,8,1,12,1,4,
     1,10,2,4,1,6,255,255,128,114,176,0,0,0,99,3,
     0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,5,
@@ -877,7 +877,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,166,0,0,0,114,42,0,0,0,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,22,95,99,111,100,101,
     95,116,111,95,116,105,109,101,115,116,97,109,112,95,112,121,
-    99,129,2,0,0,115,14,0,0,0,8,2,14,1,14,1,
+    99,130,2,0,0,115,14,0,0,0,8,2,14,1,14,1,
     14,1,16,1,4,1,255,128,114,181,0,0,0,84,99,3,
     0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,5,
     0,0,0,67,0,0,0,115,80,0,0,0,116,0,116,1,
@@ -895,7 +895,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,90,7,99,104,101,99,107,101,100,114,42,0,0,0,
     114,17,0,0,0,114,7,0,0,0,114,7,0,0,0,114,
     8,0,0,0,218,17,95,99,111,100,101,95,116,111,95,104,
-    97,115,104,95,112,121,99,139,2,0,0,115,16,0,0,0,
+    97,115,104,95,112,121,99,140,2,0,0,115,16,0,0,0,
     8,2,12,1,14,1,16,1,10,1,16,1,4,1,255,128,
     114,182,0,0,0,99,1,0,0,0,0,0,0,0,0,0,
     0,0,5,0,0,0,6,0,0,0,67,0,0,0,115,62,
@@ -923,7 +923,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     105,110,103,90,15,110,101,119,108,105,110,101,95,100,101,99,
     111,100,101,114,114,7,0,0,0,114,7,0,0,0,114,8,
     0,0,0,218,13,100,101,99,111,100,101,95,115,111,117,114,
-    99,101,150,2,0,0,115,12,0,0,0,8,5,12,1,10,
+    99,101,151,2,0,0,115,12,0,0,0,8,5,12,1,10,
     1,12,1,20,1,255,128,114,187,0,0,0,169,2,114,151,
     0,0,0,218,26,115,117,98,109,111,100,117,108,101,95,115,
     101,97,114,99,104,95,108,111,99,97,116,105,111,110,115,99,
@@ -984,7 +984,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     8,115,117,102,102,105,120,101,115,114,193,0,0,0,90,7,
     100,105,114,110,97,109,101,114,7,0,0,0,114,7,0,0,
     0,114,8,0,0,0,218,23,115,112,101,99,95,102,114,111,
-    109,95,102,105,108,101,95,108,111,99,97,116,105,111,110,167,
+    109,95,102,105,108,101,95,108,111,99,97,116,105,111,110,168,
     2,0,0,115,74,0,0,0,8,12,4,4,10,1,2,2,
     14,1,14,1,4,1,2,251,10,7,16,8,6,1,8,3,
     14,1,14,1,10,1,6,1,4,1,2,253,4,5,8,3,
@@ -1023,7 +1023,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     72,75,69,89,95,76,79,67,65,76,95,77,65,67,72,73,
     78,69,114,20,0,0,0,114,7,0,0,0,114,7,0,0,
     0,114,8,0,0,0,218,14,95,111,112,101,110,95,114,101,
-    103,105,115,116,114,121,247,2,0,0,115,12,0,0,0,2,
+    103,105,115,116,114,121,248,2,0,0,115,12,0,0,0,2,
     2,16,1,12,1,18,1,2,255,255,128,122,36,87,105,110,
     100,111,119,115,82,101,103,105,115,116,114,121,70,105,110,100,
     101,114,46,95,111,112,101,110,95,114,101,103,105,115,116,114,
@@ -1050,7 +1050,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     116,114,121,95,107,101,121,114,21,0,0,0,90,4,104,107,
     101,121,218,8,102,105,108,101,112,97,116,104,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,218,16,95,115,101,
-    97,114,99,104,95,114,101,103,105,115,116,114,121,254,2,0,
+    97,114,99,104,95,114,101,103,105,115,116,114,121,255,2,0,
     0,115,30,0,0,0,6,2,8,1,6,2,6,1,16,1,
     6,255,2,2,12,1,26,1,18,128,4,3,12,254,6,1,
     2,255,255,128,122,38,87,105,110,100,111,119,115,82,101,103,
@@ -1073,7 +1073,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,218,6,116,97,114,103,101,116,114,210,0,0,0,
     114,151,0,0,0,114,200,0,0,0,114,198,0,0,0,114,
     7,0,0,0,114,7,0,0,0,114,8,0,0,0,218,9,
-    102,105,110,100,95,115,112,101,99,13,3,0,0,115,36,0,
+    102,105,110,100,95,115,112,101,99,14,3,0,0,115,36,0,
     0,0,10,2,8,1,4,1,2,1,12,1,12,1,6,1,
     14,1,14,1,6,1,8,1,2,1,6,254,8,3,2,252,
     4,255,2,254,255,128,122,31,87,105,110,100,111,119,115,82,
@@ -1093,7 +1093,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     169,4,114,209,0,0,0,114,150,0,0,0,114,58,0,0,
     0,114,198,0,0,0,114,7,0,0,0,114,7,0,0,0,
     114,8,0,0,0,218,11,102,105,110,100,95,109,111,100,117,
-    108,101,29,3,0,0,115,10,0,0,0,12,7,8,1,6,
+    108,101,30,3,0,0,115,10,0,0,0,12,7,8,1,6,
     1,4,2,255,128,122,33,87,105,110,100,111,119,115,82,101,
     103,105,115,116,114,121,70,105,110,100,101,114,46,102,105,110,
     100,95,109,111,100,117,108,101,41,2,78,78,41,1,78,41,
@@ -1105,7 +1105,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     104,111,100,114,204,0,0,0,218,11,99,108,97,115,115,109,
     101,116,104,111,100,114,211,0,0,0,114,214,0,0,0,114,
     217,0,0,0,114,7,0,0,0,114,7,0,0,0,114,7,
-    0,0,0,114,8,0,0,0,114,202,0,0,0,235,2,0,
+    0,0,0,114,8,0,0,0,114,202,0,0,0,236,2,0,
     0,115,32,0,0,0,8,0,4,2,2,3,2,255,2,4,
     2,255,12,3,2,2,10,1,2,6,10,1,2,14,12,1,
     2,15,16,1,255,128,114,202,0,0,0,99,0,0,0,0,
@@ -1142,7 +1142,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     108,0,0,0,90,13,102,105,108,101,110,97,109,101,95,98,
     97,115,101,90,9,116,97,105,108,95,110,97,109,101,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,193,0,
-    0,0,48,3,0,0,115,10,0,0,0,18,3,16,1,14,
+    0,0,49,3,0,0,115,10,0,0,0,18,3,16,1,14,
     1,16,1,255,128,122,24,95,76,111,97,100,101,114,66,97,
     115,105,99,115,46,105,115,95,112,97,99,107,97,103,101,99,
     2,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,
@@ -1152,7 +1152,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     101,32,99,114,101,97,116,105,111,110,46,78,114,7,0,0,
     0,169,2,114,130,0,0,0,114,198,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,13,99,114,
-    101,97,116,101,95,109,111,100,117,108,101,56,3,0,0,243,
+    101,97,116,101,95,109,111,100,117,108,101,57,3,0,0,243,
     4,0,0,0,4,0,255,128,122,27,95,76,111,97,100,101,
     114,66,97,115,105,99,115,46,99,114,101,97,116,101,95,109,
     111,100,117,108,101,99,2,0,0,0,0,0,0,0,0,0,
@@ -1172,7 +1172,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     111,118,101,100,218,4,101,120,101,99,114,143,0,0,0,41,
     3,114,130,0,0,0,218,6,109,111,100,117,108,101,114,175,
     0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,218,11,101,120,101,99,95,109,111,100,117,108,101,59,
+    0,0,218,11,101,120,101,99,95,109,111,100,117,108,101,60,
     3,0,0,115,14,0,0,0,12,2,8,1,6,1,4,1,
     6,255,20,2,255,128,122,25,95,76,111,97,100,101,114,66,
     97,115,105,99,115,46,101,120,101,99,95,109,111,100,117,108,
@@ -1184,14 +1184,14 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,218,17,95,108,111,97,100,95,109,111,100,117,108,101,95,
     115,104,105,109,169,2,114,130,0,0,0,114,150,0,0,0,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,218,
-    11,108,111,97,100,95,109,111,100,117,108,101,67,3,0,0,
+    11,108,111,97,100,95,109,111,100,117,108,101,68,3,0,0,
     115,4,0,0,0,12,3,255,128,122,25,95,76,111,97,100,
     101,114,66,97,115,105,99,115,46,108,111,97,100,95,109,111,
     100,117,108,101,78,41,8,114,137,0,0,0,114,136,0,0,
     0,114,138,0,0,0,114,139,0,0,0,114,193,0,0,0,
     114,226,0,0,0,114,232,0,0,0,114,235,0,0,0,114,
     7,0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,222,0,0,0,43,3,0,0,115,14,0,0,
+    0,0,0,114,222,0,0,0,44,3,0,0,115,14,0,0,
     0,8,0,4,2,8,3,8,8,8,3,12,8,255,128,114,
     222,0,0,0,99,0,0,0,0,0,0,0,0,0,0,0,
     0,0,0,0,0,3,0,0,0,64,0,0,0,115,74,0,
@@ -1216,7 +1216,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,32,32,32,32,32,32,78,41,1,114,64,0,0,0,169,
     2,114,130,0,0,0,114,58,0,0,0,114,7,0,0,0,
     114,7,0,0,0,114,8,0,0,0,218,10,112,97,116,104,
-    95,109,116,105,109,101,75,3,0,0,115,4,0,0,0,4,
+    95,109,116,105,109,101,76,3,0,0,115,4,0,0,0,4,
     6,255,128,122,23,83,111,117,114,99,101,76,111,97,100,101,
     114,46,112,97,116,104,95,109,116,105,109,101,99,2,0,0,
     0,0,0,0,0,0,0,0,0,2,0,0,0,4,0,0,
@@ -1250,7 +1250,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     108,101,100,46,10,32,32,32,32,32,32,32,32,114,180,0,
     0,0,78,41,1,114,238,0,0,0,114,237,0,0,0,114,
     7,0,0,0,114,7,0,0,0,114,8,0,0,0,218,10,
-    112,97,116,104,95,115,116,97,116,115,83,3,0,0,115,4,
+    112,97,116,104,95,115,116,97,116,115,84,3,0,0,115,4,
     0,0,0,14,12,255,128,122,23,83,111,117,114,99,101,76,
     111,97,100,101,114,46,112,97,116,104,95,115,116,97,116,115,
     99,4,0,0,0,0,0,0,0,0,0,0,0,4,0,0,
@@ -1274,7 +1274,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     4,114,130,0,0,0,114,119,0,0,0,90,10,99,97,99,
     104,101,95,112,97,116,104,114,42,0,0,0,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,218,15,95,99,97,
-    99,104,101,95,98,121,116,101,99,111,100,101,97,3,0,0,
+    99,104,101,95,98,121,116,101,99,111,100,101,98,3,0,0,
     115,4,0,0,0,12,8,255,128,122,28,83,111,117,114,99,
     101,76,111,97,100,101,114,46,95,99,97,99,104,101,95,98,
     121,116,101,99,111,100,101,99,3,0,0,0,0,0,0,0,
@@ -1291,7 +1291,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     102,105,108,101,115,46,10,32,32,32,32,32,32,32,32,78,
     114,7,0,0,0,41,3,114,130,0,0,0,114,58,0,0,
     0,114,42,0,0,0,114,7,0,0,0,114,7,0,0,0,
-    114,8,0,0,0,114,240,0,0,0,107,3,0,0,114,227,
+    114,8,0,0,0,114,240,0,0,0,108,3,0,0,114,227,
     0,0,0,122,21,83,111,117,114,99,101,76,111,97,100,101,
     114,46,115,101,116,95,100,97,116,97,99,2,0,0,0,0,
     0,0,0,0,0,0,0,5,0,0,0,10,0,0,0,67,
@@ -1311,7 +1311,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,187,0,0,0,41,5,114,130,0,0,0,114,150,0,0,
     0,114,58,0,0,0,114,185,0,0,0,218,3,101,120,99,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,218,
-    10,103,101,116,95,115,111,117,114,99,101,114,3,0,0,115,
+    10,103,101,116,95,115,111,117,114,99,101,115,3,0,0,115,
     26,0,0,0,10,2,2,1,12,1,8,4,14,253,4,1,
     2,1,4,255,2,1,2,255,8,128,2,255,255,128,122,23,
     83,111,117,114,99,101,76,111,97,100,101,114,46,103,101,116,
@@ -1334,7 +1334,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     112,105,108,101,41,4,114,130,0,0,0,114,42,0,0,0,
     114,58,0,0,0,114,245,0,0,0,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,14,115,111,117,114,99,
-    101,95,116,111,95,99,111,100,101,124,3,0,0,115,8,0,
+    101,95,116,111,95,99,111,100,101,125,3,0,0,115,8,0,
     0,0,12,5,4,1,6,255,255,128,122,27,83,111,117,114,
     99,101,76,111,97,100,101,114,46,115,111,117,114,99,101,95,
     116,111,95,99,111,100,101,99,2,0,0,0,0,0,0,0,
@@ -1412,7 +1412,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,114,17,0,0,0,90,10,98,121,116,101,115,95,100,97,
     116,97,90,11,99,111,100,101,95,111,98,106,101,99,116,114,
     7,0,0,0,114,7,0,0,0,114,8,0,0,0,114,228,
-    0,0,0,132,3,0,0,115,170,0,0,0,10,7,4,1,
+    0,0,0,133,3,0,0,115,170,0,0,0,10,7,4,1,
     4,1,4,1,4,1,4,1,2,1,12,1,14,1,10,1,
     2,2,14,1,14,1,6,1,12,2,2,1,14,1,14,1,
     4,1,2,3,2,1,6,254,2,4,12,1,16,1,12,1,
@@ -1429,7 +1429,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     238,0,0,0,114,239,0,0,0,114,241,0,0,0,114,240,
     0,0,0,114,244,0,0,0,114,248,0,0,0,114,228,0,
     0,0,114,7,0,0,0,114,7,0,0,0,114,7,0,0,
-    0,114,8,0,0,0,114,236,0,0,0,73,3,0,0,115,
+    0,114,8,0,0,0,114,236,0,0,0,74,3,0,0,115,
     18,0,0,0,8,0,8,2,8,8,8,14,8,10,8,7,
     14,10,12,8,255,128,114,236,0,0,0,99,0,0,0,0,
     0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,
@@ -1457,7 +1457,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,32,102,105,110,100,101,114,46,78,114,170,0,0,0,41,
     3,114,130,0,0,0,114,150,0,0,0,114,58,0,0,0,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,114,
-    223,0,0,0,222,3,0,0,115,6,0,0,0,6,3,10,
+    223,0,0,0,223,3,0,0,115,6,0,0,0,6,3,10,
     1,255,128,122,19,70,105,108,101,76,111,97,100,101,114,46,
     95,95,105,110,105,116,95,95,99,2,0,0,0,0,0,0,
     0,0,0,0,0,2,0,0,0,2,0,0,0,67,0,0,
@@ -1466,7 +1466,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,169,2,218,9,95,95,99,108,97,115,115,95,95,
     114,143,0,0,0,169,2,114,130,0,0,0,90,5,111,116,
     104,101,114,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,218,6,95,95,101,113,95,95,228,3,0,0,243,8,
+    0,0,218,6,95,95,101,113,95,95,229,3,0,0,243,8,
     0,0,0,12,1,10,1,2,255,255,128,122,17,70,105,108,
     101,76,111,97,100,101,114,46,95,95,101,113,95,95,99,1,
     0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,3,
@@ -1475,7 +1475,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,121,0,0,0,169,3,218,4,104,97,115,104,114,128,0,
     0,0,114,58,0,0,0,169,1,114,130,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,218,8,95,
-    95,104,97,115,104,95,95,232,3,0,0,243,4,0,0,0,
+    95,104,97,115,104,95,95,233,3,0,0,243,4,0,0,0,
     20,1,255,128,122,19,70,105,108,101,76,111,97,100,101,114,
     46,95,95,104,97,115,104,95,95,99,2,0,0,0,0,0,
     0,0,0,0,0,0,2,0,0,0,3,0,0,0,3,0,
@@ -1489,7 +1489,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     116,101,97,100,46,10,10,32,32,32,32,32,32,32,32,78,
     41,3,218,5,115,117,112,101,114,114,254,0,0,0,114,235,
     0,0,0,114,234,0,0,0,169,1,114,1,1,0,0,114,
-    7,0,0,0,114,8,0,0,0,114,235,0,0,0,235,3,
+    7,0,0,0,114,8,0,0,0,114,235,0,0,0,236,3,
     0,0,115,4,0,0,0,16,10,255,128,122,22,70,105,108,
     101,76,111,97,100,101,114,46,108,111,97,100,95,109,111,100,
     117,108,101,99,2,0,0,0,0,0,0,0,0,0,0,0,
@@ -1500,7 +1500,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,102,111,117,110,100,32,98,121,32,116,104,101,32,102,105,
     110,100,101,114,46,78,114,62,0,0,0,114,234,0,0,0,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,114,
-    190,0,0,0,247,3,0,0,243,4,0,0,0,6,3,255,
+    190,0,0,0,248,3,0,0,243,4,0,0,0,6,3,255,
     128,122,23,70,105,108,101,76,111,97,100,101,114,46,103,101,
     116,95,102,105,108,101,110,97,109,101,99,2,0,0,0,0,
     0,0,0,0,0,0,0,3,0,0,0,8,0,0,0,67,
@@ -1521,7 +1521,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     112,101,110,95,99,111,100,101,114,97,0,0,0,90,4,114,
     101,97,100,114,80,0,0,0,41,3,114,130,0,0,0,114,
     58,0,0,0,114,83,0,0,0,114,7,0,0,0,114,7,
-    0,0,0,114,8,0,0,0,114,242,0,0,0,252,3,0,
+    0,0,0,114,8,0,0,0,114,242,0,0,0,253,3,0,
     0,115,16,0,0,0,14,2,16,1,22,1,20,128,14,2,
     22,1,20,128,255,128,122,19,70,105,108,101,76,111,97,100,
     101,114,46,103,101,116,95,100,97,116,97,99,2,0,0,0,
@@ -1534,7 +1534,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     130,0,0,0,114,231,0,0,0,114,18,1,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,218,19,103,
     101,116,95,114,101,115,111,117,114,99,101,95,114,101,97,100,
-    101,114,5,4,0,0,115,6,0,0,0,12,2,8,1,255,
+    101,114,6,4,0,0,115,6,0,0,0,12,2,8,1,255,
     128,122,30,70,105,108,101,76,111,97,100,101,114,46,103,101,
     116,95,114,101,115,111,117,114,99,101,95,114,101,97,100,101,
     114,41,13,114,137,0,0,0,114,136,0,0,0,114,138,0,
@@ -1543,7 +1543,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,190,0,0,0,114,242,0,0,0,114,19,1,0,0,90,
     13,95,95,99,108,97,115,115,99,101,108,108,95,95,114,7,
     0,0,0,114,7,0,0,0,114,12,1,0,0,114,8,0,
-    0,0,114,254,0,0,0,217,3,0,0,115,26,0,0,0,
+    0,0,114,254,0,0,0,218,3,0,0,115,26,0,0,0,
     8,0,4,2,8,3,8,6,8,4,2,3,14,1,2,11,
     10,1,8,4,2,9,18,1,255,128,114,254,0,0,0,99,
     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
@@ -1566,7 +1566,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     95,109,116,105,109,101,90,7,115,116,95,115,105,122,101,41,
     3,114,130,0,0,0,114,58,0,0,0,114,253,0,0,0,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,114,
-    239,0,0,0,15,4,0,0,115,6,0,0,0,8,2,14,
+    239,0,0,0,16,4,0,0,115,6,0,0,0,8,2,14,
     1,255,128,122,27,83,111,117,114,99,101,70,105,108,101,76,
     111,97,100,101,114,46,112,97,116,104,95,115,116,97,116,115,
     99,4,0,0,0,0,0,0,0,0,0,0,0,5,0,0,
@@ -1576,7 +1576,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     100,101,41,2,114,126,0,0,0,114,240,0,0,0,41,5,
     114,130,0,0,0,114,119,0,0,0,114,118,0,0,0,114,
     42,0,0,0,114,66,0,0,0,114,7,0,0,0,114,7,
-    0,0,0,114,8,0,0,0,114,241,0,0,0,20,4,0,
+    0,0,0,114,8,0,0,0,114,241,0,0,0,21,4,0,
     0,115,6,0,0,0,8,2,16,1,255,128,122,32,83,111,
     117,114,99,101,70,105,108,101,76,111,97,100,101,114,46,95,
     99,97,99,104,101,95,98,121,116,101,99,111,100,101,114,75,
@@ -1612,7 +1612,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,218,6,112,97,114,101,110,116,114,108,0,0,0,114,53,
     0,0,0,114,49,0,0,0,114,243,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,114,240,0,0,
-    0,25,4,0,0,115,58,0,0,0,12,2,4,1,12,2,
+    0,26,4,0,0,115,58,0,0,0,12,2,4,1,12,2,
     12,1,10,1,12,254,12,4,10,1,2,1,14,1,12,1,
     4,2,14,1,6,3,4,1,4,255,16,2,8,128,2,1,
     12,1,18,1,14,1,8,2,2,1,18,255,8,128,2,254,
@@ -1621,7 +1621,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     41,7,114,137,0,0,0,114,136,0,0,0,114,138,0,0,
     0,114,139,0,0,0,114,239,0,0,0,114,241,0,0,0,
     114,240,0,0,0,114,7,0,0,0,114,7,0,0,0,114,
-    7,0,0,0,114,8,0,0,0,114,20,1,0,0,11,4,
+    7,0,0,0,114,8,0,0,0,114,20,1,0,0,12,4,
     0,0,115,12,0,0,0,8,0,4,2,8,2,8,5,18,
     5,255,128,114,20,1,0,0,99,0,0,0,0,0,0,0,
     0,0,0,0,0,0,0,0,0,2,0,0,0,64,0,0,
@@ -1644,7 +1644,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,41,5,114,130,0,0,0,114,150,0,0,0,114,
     58,0,0,0,114,42,0,0,0,114,162,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,228,0,
-    0,0,60,4,0,0,115,24,0,0,0,10,1,10,1,2,
+    0,0,61,4,0,0,115,24,0,0,0,10,1,10,1,2,
     4,2,1,6,254,12,4,2,1,14,1,2,1,2,1,6,
     253,255,128,122,29,83,111,117,114,99,101,108,101,115,115,70,
     105,108,101,76,111,97,100,101,114,46,103,101,116,95,99,111,
@@ -1654,13 +1654,13 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     97,115,32,116,104,101,114,101,32,105,115,32,110,111,32,115,
     111,117,114,99,101,32,99,111,100,101,46,78,114,7,0,0,
     0,114,234,0,0,0,114,7,0,0,0,114,7,0,0,0,
-    114,8,0,0,0,114,244,0,0,0,76,4,0,0,114,25,
+    114,8,0,0,0,114,244,0,0,0,77,4,0,0,114,25,
     0,0,0,122,31,83,111,117,114,99,101,108,101,115,115,70,
     105,108,101,76,111,97,100,101,114,46,103,101,116,95,115,111,
     117,114,99,101,78,41,6,114,137,0,0,0,114,136,0,0,
     0,114,138,0,0,0,114,139,0,0,0,114,228,0,0,0,
     114,244,0,0,0,114,7,0,0,0,114,7,0,0,0,114,
-    7,0,0,0,114,8,0,0,0,114,26,1,0,0,56,4,
+    7,0,0,0,114,8,0,0,0,114,26,1,0,0,57,4,
     0,0,115,10,0,0,0,8,0,4,2,8,2,12,16,255,
     128,114,26,1,0,0,99,0,0,0,0,0,0,0,0,0,
     0,0,0,0,0,0,0,3,0,0,0,64,0,0,0,115,
@@ -1682,20 +1682,20 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     100,0,83,0,114,121,0,0,0,114,170,0,0,0,41,3,
     114,130,0,0,0,114,128,0,0,0,114,58,0,0,0,114,
     7,0,0,0,114,7,0,0,0,114,8,0,0,0,114,223,
-    0,0,0,89,4,0,0,115,6,0,0,0,6,1,10,1,
+    0,0,0,90,4,0,0,115,6,0,0,0,6,1,10,1,
     255,128,122,28,69,120,116,101,110,115,105,111,110,70,105,108,
     101,76,111,97,100,101,114,46,95,95,105,110,105,116,95,95,
     99,2,0,0,0,0,0,0,0,0,0,0,0,2,0,0,
     0,2,0,0,0,67,0,0,0,114,255,0,0,0,114,121,
     0,0,0,114,0,1,0,0,114,2,1,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,114,3,1,0,
-    0,93,4,0,0,114,4,1,0,0,122,26,69,120,116,101,
+    0,94,4,0,0,114,4,1,0,0,122,26,69,120,116,101,
     110,115,105,111,110,70,105,108,101,76,111,97,100,101,114,46,
     95,95,101,113,95,95,99,1,0,0,0,0,0,0,0,0,
     0,0,0,1,0,0,0,3,0,0,0,67,0,0,0,114,
     5,1,0,0,114,121,0,0,0,114,6,1,0,0,114,8,
     1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,114,9,1,0,0,97,4,0,0,114,10,1,0,0,
+    0,0,114,9,1,0,0,98,4,0,0,114,10,1,0,0,
     122,28,69,120,116,101,110,115,105,111,110,70,105,108,101,76,
     111,97,100,101,114,46,95,95,104,97,115,104,95,95,99,2,
     0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,5,
@@ -1712,7 +1712,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     97,109,105,99,114,160,0,0,0,114,128,0,0,0,114,58,
     0,0,0,41,3,114,130,0,0,0,114,198,0,0,0,114,
     231,0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,226,0,0,0,100,4,0,0,115,16,0,0,
+    0,0,0,114,226,0,0,0,101,4,0,0,115,16,0,0,
     0,4,2,6,1,4,255,6,2,8,1,4,255,4,2,255,
     128,122,33,69,120,116,101,110,115,105,111,110,70,105,108,101,
     76,111,97,100,101,114,46,99,114,101,97,116,101,95,109,111,
@@ -1730,7 +1730,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     105,99,114,160,0,0,0,114,128,0,0,0,114,58,0,0,
     0,169,2,114,130,0,0,0,114,231,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,114,232,0,0,
-    0,108,4,0,0,115,10,0,0,0,14,2,6,1,8,1,
+    0,109,4,0,0,115,10,0,0,0,14,2,6,1,8,1,
     8,255,255,128,122,31,69,120,116,101,110,115,105,111,110,70,
     105,108,101,76,111,97,100,101,114,46,101,120,101,99,95,109,
     111,100,117,108,101,99,2,0,0,0,0,0,0,0,0,0,
@@ -1748,14 +1748,14 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     78,114,7,0,0,0,169,2,114,5,0,0,0,218,6,115,
     117,102,102,105,120,169,1,90,9,102,105,108,101,95,110,97,
     109,101,114,7,0,0,0,114,8,0,0,0,114,9,0,0,
-    0,117,4,0,0,115,8,0,0,0,4,0,2,1,20,255,
+    0,118,4,0,0,115,8,0,0,0,4,0,2,1,20,255,
     255,128,122,49,69,120,116,101,110,115,105,111,110,70,105,108,
     101,76,111,97,100,101,114,46,105,115,95,112,97,99,107,97,
     103,101,46,60,108,111,99,97,108,115,62,46,60,103,101,110,
     101,120,112,114,62,78,41,4,114,61,0,0,0,114,58,0,
     0,0,218,3,97,110,121,114,219,0,0,0,114,234,0,0,
     0,114,7,0,0,0,114,30,1,0,0,114,8,0,0,0,
-    114,193,0,0,0,114,4,0,0,115,10,0,0,0,14,2,
+    114,193,0,0,0,115,4,0,0,115,10,0,0,0,14,2,
     12,1,2,1,8,255,255,128,122,30,69,120,116,101,110,115,
     105,111,110,70,105,108,101,76,111,97,100,101,114,46,105,115,
     95,112,97,99,107,97,103,101,99,2,0,0,0,0,0,0,
@@ -1766,7 +1766,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     110,111,116,32,99,114,101,97,116,101,32,97,32,99,111,100,
     101,32,111,98,106,101,99,116,46,78,114,7,0,0,0,114,
     234,0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,228,0,0,0,120,4,0,0,114,25,0,0,
+    0,0,0,114,228,0,0,0,121,4,0,0,114,25,0,0,
     0,122,28,69,120,116,101,110,115,105,111,110,70,105,108,101,
     76,111,97,100,101,114,46,103,101,116,95,99,111,100,101,99,
     2,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,
@@ -1776,13 +1776,13 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     115,32,104,97,118,101,32,110,111,32,115,111,117,114,99,101,
     32,99,111,100,101,46,78,114,7,0,0,0,114,234,0,0,
     0,114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,
-    114,244,0,0,0,124,4,0,0,114,25,0,0,0,122,30,
+    114,244,0,0,0,125,4,0,0,114,25,0,0,0,122,30,
     69,120,116,101,110,115,105,111,110,70,105,108,101,76,111,97,
     100,101,114,46,103,101,116,95,115,111,117,114,99,101,99,2,
     0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,1,
     0,0,0,67,0,0,0,114,13,1,0,0,114,14,1,0,
     0,114,62,0,0,0,114,234,0,0,0,114,7,0,0,0,
-    114,7,0,0,0,114,8,0,0,0,114,190,0,0,0,128,
+    114,7,0,0,0,114,8,0,0,0,114,190,0,0,0,129,
     4,0,0,114,15,1,0,0,122,32,69,120,116,101,110,115,
     105,111,110,70,105,108,101,76,111,97,100,101,114,46,103,101,
     116,95,102,105,108,101,110,97,109,101,78,41,14,114,137,0,
@@ -1791,7 +1791,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,226,0,0,0,114,232,0,0,0,114,193,0,0,0,114,
     228,0,0,0,114,244,0,0,0,114,147,0,0,0,114,190,
     0,0,0,114,7,0,0,0,114,7,0,0,0,114,7,0,
-    0,0,114,8,0,0,0,114,17,1,0,0,81,4,0,0,
+    0,0,114,8,0,0,0,114,17,1,0,0,82,4,0,0,
     115,26,0,0,0,8,0,4,2,8,6,8,4,8,4,8,
     3,8,8,8,6,8,6,8,4,2,4,14,1,255,128,114,
     17,1,0,0,99,0,0,0,0,0,0,0,0,0,0,0,
@@ -1834,7 +1834,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     102,105,110,100,101,114,169,4,114,130,0,0,0,114,128,0,
     0,0,114,58,0,0,0,90,11,112,97,116,104,95,102,105,
     110,100,101,114,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,223,0,0,0,141,4,0,0,115,10,0,0,
+    0,0,0,114,223,0,0,0,142,4,0,0,115,10,0,0,
     0,6,1,6,1,14,1,10,1,255,128,122,23,95,78,97,
     109,101,115,112,97,99,101,80,97,116,104,46,95,95,105,110,
     105,116,95,95,99,1,0,0,0,0,0,0,0,0,0,0,
@@ -1852,7 +1852,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     1,0,0,218,3,100,111,116,90,2,109,101,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,218,23,95,102,105,
     110,100,95,112,97,114,101,110,116,95,112,97,116,104,95,110,
-    97,109,101,115,147,4,0,0,115,10,0,0,0,18,2,8,
+    97,109,101,115,148,4,0,0,115,10,0,0,0,18,2,8,
     1,4,2,8,3,255,128,122,38,95,78,97,109,101,115,112,
     97,99,101,80,97,116,104,46,95,102,105,110,100,95,112,97,
     114,101,110,116,95,112,97,116,104,95,110,97,109,101,115,99,
@@ -1865,7 +1865,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     18,112,97,114,101,110,116,95,109,111,100,117,108,101,95,110,
     97,109,101,90,14,112,97,116,104,95,97,116,116,114,95,110,
     97,109,101,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,114,35,1,0,0,157,4,0,0,115,6,0,0,0,
+    0,0,114,35,1,0,0,158,4,0,0,115,6,0,0,0,
     12,1,16,1,255,128,122,31,95,78,97,109,101,115,112,97,
     99,101,80,97,116,104,46,95,103,101,116,95,112,97,114,101,
     110,116,95,112,97,116,104,99,1,0,0,0,0,0,0,0,
@@ -1881,7 +1881,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     34,1,0,0,41,3,114,130,0,0,0,90,11,112,97,114,
     101,110,116,95,112,97,116,104,114,198,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,12,95,114,
-    101,99,97,108,99,117,108,97,116,101,161,4,0,0,115,18,
+    101,99,97,108,99,117,108,97,116,101,162,4,0,0,115,18,
     0,0,0,12,2,10,1,14,1,18,3,6,1,8,1,6,
     1,6,1,255,128,122,27,95,78,97,109,101,115,112,97,99,
     101,80,97,116,104,46,95,114,101,99,97,108,99,117,108,97,
@@ -1890,7 +1890,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     116,0,124,0,160,1,161,0,131,1,83,0,114,121,0,0,
     0,41,2,218,4,105,116,101,114,114,42,1,0,0,114,8,
     1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,218,8,95,95,105,116,101,114,95,95,174,4,0,0,
+    0,0,218,8,95,95,105,116,101,114,95,95,175,4,0,0,
     243,4,0,0,0,12,1,255,128,122,23,95,78,97,109,101,
     115,112,97,99,101,80,97,116,104,46,95,95,105,116,101,114,
     95,95,99,2,0,0,0,0,0,0,0,0,0,0,0,2,
@@ -1899,7 +1899,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,169,1,114,42,1,0,0,41,2,114,130,0,0,0,218,
     5,105,110,100,101,120,114,7,0,0,0,114,7,0,0,0,
     114,8,0,0,0,218,11,95,95,103,101,116,105,116,101,109,
-    95,95,177,4,0,0,114,46,1,0,0,122,26,95,78,97,
+    95,95,178,4,0,0,114,46,1,0,0,122,26,95,78,97,
     109,101,115,112,97,99,101,80,97,116,104,46,95,95,103,101,
     116,105,116,101,109,95,95,99,3,0,0,0,0,0,0,0,
     0,0,0,0,3,0,0,0,3,0,0,0,67,0,0,0,
@@ -1907,7 +1907,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,83,0,114,121,0,0,0,41,1,114,34,1,0,0,41,
     3,114,130,0,0,0,114,48,1,0,0,114,58,0,0,0,
     114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,218,
-    11,95,95,115,101,116,105,116,101,109,95,95,180,4,0,0,
+    11,95,95,115,101,116,105,116,101,109,95,95,181,4,0,0,
     115,4,0,0,0,14,1,255,128,122,26,95,78,97,109,101,
     115,112,97,99,101,80,97,116,104,46,95,95,115,101,116,105,
     116,101,109,95,95,99,1,0,0,0,0,0,0,0,0,0,
@@ -1915,7 +1915,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     1,0,0,114,121,0,0,0,41,2,114,4,0,0,0,114,
     42,1,0,0,114,8,1,0,0,114,7,0,0,0,114,7,
     0,0,0,114,8,0,0,0,218,7,95,95,108,101,110,95,
-    95,183,4,0,0,114,46,1,0,0,122,22,95,78,97,109,
+    95,184,4,0,0,114,46,1,0,0,122,22,95,78,97,109,
     101,115,112,97,99,101,80,97,116,104,46,95,95,108,101,110,
     95,95,99,1,0,0,0,0,0,0,0,0,0,0,0,1,
     0,0,0,3,0,0,0,67,0,0,0,243,12,0,0,0,
@@ -1923,7 +1923,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     20,95,78,97,109,101,115,112,97,99,101,80,97,116,104,40,
     123,33,114,125,41,41,2,114,77,0,0,0,114,34,1,0,
     0,114,8,1,0,0,114,7,0,0,0,114,7,0,0,0,
-    114,8,0,0,0,218,8,95,95,114,101,112,114,95,95,186,
+    114,8,0,0,0,218,8,95,95,114,101,112,114,95,95,187,
     4,0,0,114,46,1,0,0,122,23,95,78,97,109,101,115,
     112,97,99,101,80,97,116,104,46,95,95,114,101,112,114,95,
     95,99,2,0,0,0,0,0,0,0,0,0,0,0,2,0,
@@ -1931,7 +1931,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     1,124,0,160,0,161,0,118,0,83,0,114,121,0,0,0,
     114,47,1,0,0,169,2,114,130,0,0,0,218,4,105,116,
     101,109,114,7,0,0,0,114,7,0,0,0,114,8,0,0,
-    0,218,12,95,95,99,111,110,116,97,105,110,115,95,95,189,
+    0,218,12,95,95,99,111,110,116,97,105,110,115,95,95,190,
     4,0,0,114,46,1,0,0,122,27,95,78,97,109,101,115,
     112,97,99,101,80,97,116,104,46,95,95,99,111,110,116,97,
     105,110,115,95,95,99,2,0,0,0,0,0,0,0,0,0,
@@ -1939,7 +1939,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,0,124,0,106,0,160,1,124,1,161,1,1,0,100,
     0,83,0,114,121,0,0,0,41,2,114,34,1,0,0,114,
     197,0,0,0,114,54,1,0,0,114,7,0,0,0,114,7,
-    0,0,0,114,8,0,0,0,114,197,0,0,0,192,4,0,
+    0,0,0,114,8,0,0,0,114,197,0,0,0,193,4,0,
     0,243,4,0,0,0,16,1,255,128,122,21,95,78,97,109,
     101,115,112,97,99,101,80,97,116,104,46,97,112,112,101,110,
     100,78,41,15,114,137,0,0,0,114,136,0,0,0,114,138,
@@ -1948,7 +1948,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,114,49,1,0,0,114,50,1,0,0,114,51,1,0,0,
     114,53,1,0,0,114,56,1,0,0,114,197,0,0,0,114,
     7,0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,32,1,0,0,134,4,0,0,115,28,0,0,
+    0,0,0,114,32,1,0,0,135,4,0,0,115,28,0,0,
     0,8,0,4,1,8,6,8,6,8,10,8,4,8,13,8,
     3,8,3,8,3,8,3,8,3,12,3,255,128,114,32,1,
     0,0,99,0,0,0,0,0,0,0,0,0,0,0,0,0,
@@ -1964,7 +1964,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,116,0,124,1,124,2,124,3,131,3,124,0,95,1,
     100,0,83,0,114,121,0,0,0,41,2,114,32,1,0,0,
     114,34,1,0,0,114,38,1,0,0,114,7,0,0,0,114,
-    7,0,0,0,114,8,0,0,0,114,223,0,0,0,198,4,
+    7,0,0,0,114,8,0,0,0,114,223,0,0,0,199,4,
     0,0,115,4,0,0,0,18,1,255,128,122,25,95,78,97,
     109,101,115,112,97,99,101,76,111,97,100,101,114,46,95,95,
     105,110,105,116,95,95,99,1,0,0,0,0,0,0,0,0,
@@ -1981,20 +1981,20 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     112,97,99,101,41,62,78,41,2,114,77,0,0,0,114,137,
     0,0,0,41,1,114,231,0,0,0,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,11,109,111,100,117,108,
-    101,95,114,101,112,114,201,4,0,0,115,4,0,0,0,12,
+    101,95,114,101,112,114,202,4,0,0,115,4,0,0,0,12,
     7,255,128,122,28,95,78,97,109,101,115,112,97,99,101,76,
     111,97,100,101,114,46,109,111,100,117,108,101,95,114,101,112,
     114,99,2,0,0,0,0,0,0,0,0,0,0,0,2,0,
     0,0,1,0,0,0,67,0,0,0,114,24,0,0,0,41,
     2,78,84,114,7,0,0,0,114,234,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,114,193,0,0,
-    0,210,4,0,0,243,4,0,0,0,4,1,255,128,122,27,
+    0,211,4,0,0,243,4,0,0,0,4,1,255,128,122,27,
     95,78,97,109,101,115,112,97,99,101,76,111,97,100,101,114,
     46,105,115,95,112,97,99,107,97,103,101,99,2,0,0,0,
     0,0,0,0,0,0,0,0,2,0,0,0,1,0,0,0,
     67,0,0,0,114,24,0,0,0,41,2,78,114,10,0,0,
     0,114,7,0,0,0,114,234,0,0,0,114,7,0,0,0,
-    114,7,0,0,0,114,8,0,0,0,114,244,0,0,0,213,
+    114,7,0,0,0,114,8,0,0,0,114,244,0,0,0,214,
     4,0,0,114,60,1,0,0,122,27,95,78,97,109,101,115,
     112,97,99,101,76,111,97,100,101,114,46,103,101,116,95,115,
     111,117,114,99,101,99,2,0,0,0,0,0,0,0,0,0,
@@ -2004,20 +2004,20 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,105,110,103,62,114,230,0,0,0,84,41,1,114,246,0,
     0,0,41,1,114,247,0,0,0,114,234,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,228,0,
-    0,0,216,4,0,0,114,57,1,0,0,122,25,95,78,97,
+    0,0,217,4,0,0,114,57,1,0,0,122,25,95,78,97,
     109,101,115,112,97,99,101,76,111,97,100,101,114,46,103,101,
     116,95,99,111,100,101,99,2,0,0,0,0,0,0,0,0,
     0,0,0,2,0,0,0,1,0,0,0,67,0,0,0,114,
     24,0,0,0,114,224,0,0,0,114,7,0,0,0,114,225,
     0,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,114,226,0,0,0,219,4,0,0,114,227,0,0,0,
+    0,0,114,226,0,0,0,220,4,0,0,114,227,0,0,0,
     122,30,95,78,97,109,101,115,112,97,99,101,76,111,97,100,
     101,114,46,99,114,101,97,116,101,95,109,111,100,117,108,101,
     99,2,0,0,0,0,0,0,0,0,0,0,0,2,0,0,
     0,1,0,0,0,67,0,0,0,115,4,0,0,0,100,0,
     83,0,114,121,0,0,0,114,7,0,0,0,114,27,1,0,
     0,114,7,0,0,0,114,7,0,0,0,114,8,0,0,0,
-    114,232,0,0,0,222,4,0,0,114,60,1,0,0,122,28,
+    114,232,0,0,0,223,4,0,0,114,60,1,0,0,122,28,
     95,78,97,109,101,115,112,97,99,101,76,111,97,100,101,114,
     46,101,120,101,99,95,109,111,100,117,108,101,99,2,0,0,
     0,0,0,0,0,0,0,0,0,2,0,0,0,4,0,0,
@@ -2035,7 +2035,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,125,78,41,4,114,146,0,0,0,114,160,0,0,0,114,
     34,1,0,0,114,233,0,0,0,114,234,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,235,0,
-    0,0,225,4,0,0,115,10,0,0,0,6,7,4,1,4,
+    0,0,226,4,0,0,115,10,0,0,0,6,7,4,1,4,
     255,12,3,255,128,122,28,95,78,97,109,101,115,112,97,99,
     101,76,111,97,100,101,114,46,108,111,97,100,95,109,111,100,
     117,108,101,78,41,12,114,137,0,0,0,114,136,0,0,0,
@@ -2043,7 +2043,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     59,1,0,0,114,193,0,0,0,114,244,0,0,0,114,228,
     0,0,0,114,226,0,0,0,114,232,0,0,0,114,235,0,
     0,0,114,7,0,0,0,114,7,0,0,0,114,7,0,0,
-    0,114,8,0,0,0,114,58,1,0,0,197,4,0,0,115,
+    0,114,8,0,0,0,114,58,1,0,0,198,4,0,0,115,
     22,0,0,0,8,0,8,1,2,3,10,1,8,8,8,3,
     8,3,8,3,8,3,12,3,255,128,114,58,1,0,0,99,
     0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
@@ -2080,7 +2080,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     95,99,97,99,104,101,218,5,105,116,101,109,115,114,140,0,
     0,0,114,62,1,0,0,41,2,114,128,0,0,0,218,6,
     102,105,110,100,101,114,114,7,0,0,0,114,7,0,0,0,
-    114,8,0,0,0,114,62,1,0,0,244,4,0,0,115,16,
+    114,8,0,0,0,114,62,1,0,0,245,4,0,0,115,16,
     0,0,0,22,4,8,1,10,1,10,1,8,1,2,128,4,
     252,255,128,122,28,80,97,116,104,70,105,110,100,101,114,46,
     105,110,118,97,108,105,100,97,116,101,95,99,97,99,104,101,
@@ -2100,7 +2100,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     89,0,0,0,114,149,0,0,0,114,129,0,0,0,41,2,
     114,58,0,0,0,90,4,104,111,111,107,114,7,0,0,0,
     114,7,0,0,0,114,8,0,0,0,218,11,95,112,97,116,
-    104,95,104,111,111,107,115,254,4,0,0,115,20,0,0,0,
+    104,95,104,111,111,107,115,255,4,0,0,115,20,0,0,0,
     16,3,12,1,10,1,2,1,14,1,12,1,4,1,4,2,
     2,253,255,128,122,22,80,97,116,104,70,105,110,100,101,114,
     46,95,112,97,116,104,95,104,111,111,107,115,99,2,0,0,
@@ -2132,7 +2132,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,41,3,114,209,0,0,0,114,58,0,0,0,114,66,
     1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
     0,0,218,20,95,112,97,116,104,95,105,109,112,111,114,116,
-    101,114,95,99,97,99,104,101,11,5,0,0,115,30,0,0,
+    101,114,95,99,97,99,104,101,12,5,0,0,115,30,0,0,
     0,8,8,2,1,12,1,12,1,6,3,2,1,12,1,4,
     4,12,253,10,1,12,1,4,1,2,253,2,250,255,128,122,
     31,80,97,116,104,70,105,110,100,101,114,46,95,112,97,116,
@@ -2150,7 +2150,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     209,0,0,0,114,150,0,0,0,114,66,1,0,0,114,151,
     0,0,0,114,152,0,0,0,114,198,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,16,95,108,
-    101,103,97,99,121,95,103,101,116,95,115,112,101,99,33,5,
+    101,103,97,99,121,95,103,101,116,95,115,112,101,99,34,5,
     0,0,115,20,0,0,0,10,4,16,1,10,2,4,1,8,
     1,12,1,12,1,6,1,4,1,255,128,122,27,80,97,116,
     104,70,105,110,100,101,114,46,95,108,101,103,97,99,121,95,
@@ -2182,7 +2182,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     101,95,112,97,116,104,90,5,101,110,116,114,121,114,66,1,
     0,0,114,198,0,0,0,114,152,0,0,0,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,218,9,95,103,101,
-    116,95,115,112,101,99,48,5,0,0,115,44,0,0,0,4,
+    116,95,115,112,101,99,49,5,0,0,115,44,0,0,0,4,
     5,8,1,14,1,2,1,10,1,8,1,10,1,14,1,12,
     2,8,1,2,1,10,1,8,1,6,1,8,1,8,1,10,
     5,2,128,12,2,6,1,4,1,255,128,122,20,80,97,116,
@@ -2209,7 +2209,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,1,0,0,41,6,114,209,0,0,0,114,150,0,0,0,
     114,58,0,0,0,114,213,0,0,0,114,198,0,0,0,114,
     74,1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,214,0,0,0,80,5,0,0,115,28,0,0,
+    0,0,0,114,214,0,0,0,81,5,0,0,115,28,0,0,
     0,8,6,6,1,14,1,8,1,4,1,10,1,6,1,4,
     1,6,3,16,1,4,1,4,2,4,2,255,128,122,20,80,
     97,116,104,70,105,110,100,101,114,46,102,105,110,100,95,115,
@@ -2229,7 +2229,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     105,110,100,95,115,112,101,99,40,41,32,105,110,115,116,101,
     97,100,46,10,10,32,32,32,32,32,32,32,32,78,114,215,
     0,0,0,114,216,0,0,0,114,7,0,0,0,114,7,0,
-    0,0,114,8,0,0,0,114,217,0,0,0,104,5,0,0,
+    0,0,114,8,0,0,0,114,217,0,0,0,105,5,0,0,
     115,10,0,0,0,12,8,8,1,4,1,6,1,255,128,122,
     22,80,97,116,104,70,105,110,100,101,114,46,102,105,110,100,
     95,109,111,100,117,108,101,99,0,0,0,0,0,0,0,0,
@@ -2261,7 +2261,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     18,102,105,110,100,95,100,105,115,116,114,105,98,117,116,105,
     111,110,115,41,3,114,131,0,0,0,114,132,0,0,0,114,
     76,1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,114,77,1,0,0,117,5,0,0,115,6,0,0,
+    0,0,0,114,77,1,0,0,118,5,0,0,115,6,0,0,
     0,12,10,16,1,255,128,122,29,80,97,116,104,70,105,110,
     100,101,114,46,102,105,110,100,95,100,105,115,116,114,105,98,
     117,116,105,111,110,115,41,1,78,41,2,78,78,41,1,78,
@@ -2271,7 +2271,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     72,1,0,0,114,75,1,0,0,114,214,0,0,0,114,217,
     0,0,0,114,77,1,0,0,114,7,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,114,61,1,0,
-    0,240,4,0,0,115,38,0,0,0,8,0,4,2,2,2,
+    0,241,4,0,0,115,38,0,0,0,8,0,4,2,2,2,
     10,1,2,9,10,1,2,12,10,1,2,21,10,1,2,14,
     12,1,2,31,12,1,2,23,12,1,2,12,14,1,255,128,
     114,61,1,0,0,99,0,0,0,0,0,0,0,0,0,0,
@@ -2316,7 +2316,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,102,2,86,0,1,0,113,2,100,0,83,0,114,121,0,
     0,0,114,7,0,0,0,114,28,1,0,0,169,1,114,151,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,9,0,
-    0,0,146,5,0,0,114,14,0,0,0,122,38,70,105,108,
+    0,0,147,5,0,0,114,14,0,0,0,122,38,70,105,108,
     101,70,105,110,100,101,114,46,95,95,105,110,105,116,95,95,
     46,60,108,111,99,97,108,115,62,46,60,103,101,110,101,120,
     112,114,62,114,86,0,0,0,114,116,0,0,0,78,41,7,
@@ -2328,7 +2328,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     58,0,0,0,218,14,108,111,97,100,101,114,95,100,101,116,
     97,105,108,115,90,7,108,111,97,100,101,114,115,114,200,0,
     0,0,114,7,0,0,0,114,79,1,0,0,114,8,0,0,
-    0,114,223,0,0,0,140,5,0,0,115,18,0,0,0,4,
+    0,114,223,0,0,0,141,5,0,0,115,18,0,0,0,4,
     4,12,1,26,1,6,1,10,2,6,1,8,1,12,1,255,
     128,122,19,70,105,108,101,70,105,110,100,101,114,46,95,95,
     105,110,105,116,95,95,99,1,0,0,0,0,0,0,0,0,
@@ -2338,7 +2338,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,100,105,114,101,99,116,111,114,121,32,109,116,105,109,101,
     46,114,116,0,0,0,78,41,1,114,81,1,0,0,114,8,
     1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,114,62,1,0,0,154,5,0,0,114,69,0,0,0,
+    0,0,114,62,1,0,0,155,5,0,0,114,69,0,0,0,
     122,28,70,105,108,101,70,105,110,100,101,114,46,105,110,118,
     97,108,105,100,97,116,101,95,99,97,99,104,101,115,99,2,
     0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,3,
@@ -2361,7 +2361,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     41,3,114,214,0,0,0,114,151,0,0,0,114,189,0,0,
     0,41,3,114,130,0,0,0,114,150,0,0,0,114,198,0,
     0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,0,
-    0,114,148,0,0,0,160,5,0,0,115,10,0,0,0,10,
+    0,114,148,0,0,0,161,5,0,0,115,10,0,0,0,10,
     7,8,1,8,1,16,1,255,128,122,22,70,105,108,101,70,
     105,110,100,101,114,46,102,105,110,100,95,108,111,97,100,101,
     114,99,6,0,0,0,0,0,0,0,0,0,0,0,7,0,
@@ -2372,7 +2372,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     199,0,0,0,114,150,0,0,0,114,58,0,0,0,90,4,
     115,109,115,108,114,213,0,0,0,114,151,0,0,0,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,75,1,
-    0,0,172,5,0,0,115,10,0,0,0,10,1,8,1,2,
+    0,0,173,5,0,0,115,10,0,0,0,10,1,8,1,2,
     1,6,255,255,128,122,20,70,105,108,101,70,105,110,100,101,
     114,46,95,103,101,116,95,115,112,101,99,78,99,3,0,0,
     0,0,0,0,0,0,0,0,0,14,0,0,0,8,0,0,
@@ -2427,7 +2427,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     110,105,116,95,102,105,108,101,110,97,109,101,90,9,102,117,
     108,108,95,112,97,116,104,114,198,0,0,0,114,7,0,0,
     0,114,7,0,0,0,114,8,0,0,0,114,214,0,0,0,
-    177,5,0,0,115,80,0,0,0,4,5,14,1,2,1,24,
+    178,5,0,0,115,80,0,0,0,4,5,14,1,2,1,24,
     1,14,1,6,1,10,1,8,1,6,1,6,2,6,1,10,
     1,6,2,4,1,8,2,12,1,14,1,8,1,10,1,8,
     1,24,1,2,255,8,5,14,2,16,1,16,1,14,1,10,
@@ -2458,7 +2458,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     104,0,124,0,93,12,125,1,124,1,160,0,161,0,146,2,
     113,4,83,0,114,7,0,0,0,41,1,114,117,0,0,0,
     41,2,114,5,0,0,0,90,2,102,110,114,7,0,0,0,
-    114,7,0,0,0,114,8,0,0,0,114,13,0,0,0,254,
+    114,7,0,0,0,114,8,0,0,0,114,13,0,0,0,255,
     5,0,0,115,4,0,0,0,20,0,255,128,122,41,70,105,
     108,101,70,105,110,100,101,114,46,95,102,105,108,108,95,99,
     97,99,104,101,46,60,108,111,99,97,108,115,62,46,60,115,
@@ -2476,7 +2476,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,55,1,0,0,114,128,0,0,0,114,39,1,0,0,114,
     29,1,0,0,90,8,110,101,119,95,110,97,109,101,114,7,
     0,0,0,114,7,0,0,0,114,8,0,0,0,114,86,1,
-    0,0,225,5,0,0,115,40,0,0,0,6,2,2,1,22,
+    0,0,226,5,0,0,115,40,0,0,0,6,2,2,1,22,
     1,18,1,6,3,12,3,12,1,6,7,8,1,16,1,4,
     1,18,1,4,2,12,1,6,1,12,1,20,1,4,255,2,
     233,255,128,122,22,70,105,108,101,70,105,110,100,101,114,46,
@@ -2515,14 +2515,14 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     169,2,114,209,0,0,0,114,85,1,0,0,114,7,0,0,
     0,114,8,0,0,0,218,24,112,97,116,104,95,104,111,111,
     107,95,102,111,114,95,70,105,108,101,70,105,110,100,101,114,
-    10,6,0,0,115,8,0,0,0,8,2,12,1,16,1,255,
+    11,6,0,0,115,8,0,0,0,8,2,12,1,16,1,255,
     128,122,54,70,105,108,101,70,105,110,100,101,114,46,112,97,
     116,104,95,104,111,111,107,46,60,108,111,99,97,108,115,62,
     46,112,97,116,104,95,104,111,111,107,95,102,111,114,95,70,
     105,108,101,70,105,110,100,101,114,78,114,7,0,0,0,41,
     3,114,209,0,0,0,114,85,1,0,0,114,91,1,0,0,
     114,7,0,0,0,114,90,1,0,0,114,8,0,0,0,218,
-    9,112,97,116,104,95,104,111,111,107,0,6,0,0,115,6,
+    9,112,97,116,104,95,104,111,111,107,1,6,0,0,115,6,
     0,0,0,14,10,4,6,255,128,122,20,70,105,108,101,70,
     105,110,100,101,114,46,112,97,116,104,95,104,111,111,107,99,
     1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,
@@ -2530,7 +2530,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     122,16,70,105,108,101,70,105,110,100,101,114,40,123,33,114,
     125,41,41,2,114,77,0,0,0,114,58,0,0,0,114,8,
     1,0,0,114,7,0,0,0,114,7,0,0,0,114,8,0,
-    0,0,114,53,1,0,0,18,6,0,0,114,46,1,0,0,
+    0,0,114,53,1,0,0,19,6,0,0,114,46,1,0,0,
     122,19,70,105,108,101,70,105,110,100,101,114,46,95,95,114,
     101,112,114,95,95,41,1,78,41,15,114,137,0,0,0,114,
     136,0,0,0,114,138,0,0,0,114,139,0,0,0,114,223,
@@ -2538,7 +2538,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,114,148,0,0,0,114,75,1,0,0,114,214,0,0,
     0,114,86,1,0,0,114,221,0,0,0,114,92,1,0,0,
     114,53,1,0,0,114,7,0,0,0,114,7,0,0,0,114,
-    7,0,0,0,114,8,0,0,0,114,78,1,0,0,131,5,
+    7,0,0,0,114,8,0,0,0,114,78,1,0,0,132,5,
     0,0,115,26,0,0,0,8,0,4,2,8,7,8,14,4,
     4,8,2,8,12,10,5,8,48,2,31,10,1,12,17,255,
     128,114,78,1,0,0,99,4,0,0,0,0,0,0,0,0,
@@ -2562,7 +2562,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     97,109,101,90,9,99,112,97,116,104,110,97,109,101,114,151,
     0,0,0,114,198,0,0,0,114,7,0,0,0,114,7,0,
     0,0,114,8,0,0,0,218,14,95,102,105,120,95,117,112,
-    95,109,111,100,117,108,101,24,6,0,0,115,38,0,0,0,
+    95,109,111,100,117,108,101,25,6,0,0,115,38,0,0,0,
     10,2,10,1,4,1,4,1,8,1,8,1,12,1,10,2,
     4,1,14,1,2,1,8,1,8,1,8,1,14,1,12,1,
     6,2,2,254,255,128,114,97,1,0,0,99,0,0,0,0,
@@ -2582,7 +2582,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,0,114,101,0,0,0,41,3,90,10,101,120,116,101,110,
     115,105,111,110,115,90,6,115,111,117,114,99,101,90,8,98,
     121,116,101,99,111,100,101,114,7,0,0,0,114,7,0,0,
-    0,114,8,0,0,0,114,195,0,0,0,47,6,0,0,115,
+    0,114,8,0,0,0,114,195,0,0,0,48,6,0,0,115,
     10,0,0,0,12,5,8,1,8,1,10,1,255,128,114,195,
     0,0,0,99,1,0,0,0,0,0,0,0,0,0,0,0,
     1,0,0,0,1,0,0,0,67,0,0,0,115,8,0,0,
@@ -2591,7 +2591,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,97,112,95,109,111,100,117,108,101,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,218,21,95,115,101,116,95,
     98,111,111,116,115,116,114,97,112,95,109,111,100,117,108,101,
-    58,6,0,0,115,4,0,0,0,8,2,255,128,114,100,1,
+    59,6,0,0,115,4,0,0,0,8,2,255,128,114,100,1,
     0,0,99,1,0,0,0,0,0,0,0,0,0,0,0,2,
     0,0,0,4,0,0,0,67,0,0,0,115,50,0,0,0,
     116,0,124,0,131,1,1,0,116,1,131,0,125,1,116,2,
@@ -2606,7 +2606,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     114,197,0,0,0,114,61,1,0,0,41,2,114,99,1,0,
     0,90,17,115,117,112,112,111,114,116,101,100,95,108,111,97,
     100,101,114,115,114,7,0,0,0,114,7,0,0,0,114,8,
-    0,0,0,218,8,95,105,110,115,116,97,108,108,63,6,0,
+    0,0,0,218,8,95,105,110,115,116,97,108,108,64,6,0,
     0,115,10,0,0,0,8,2,6,1,20,1,16,1,255,128,
     114,102,1,0,0,41,1,114,75,0,0,0,41,1,78,41,
     3,78,78,78,41,2,114,0,0,0,0,114,0,0,0,0,
@@ -2649,7 +2649,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     2,4,3,10,1,6,2,22,2,8,1,10,1,14,1,4,
     4,4,1,2,1,2,1,4,255,8,4,6,16,8,3,8,
     5,8,5,8,6,8,6,8,12,8,10,8,9,8,5,8,
-    7,10,9,10,22,0,127,16,24,12,1,4,2,4,1,6,
+    7,10,9,10,22,0,127,16,25,12,1,4,2,4,1,6,
     2,6,1,10,1,8,2,6,2,8,2,16,2,8,71,8,
     40,8,19,8,12,8,12,8,31,8,17,8,33,8,28,10,
     24,10,13,10,10,8,11,6,14,4,3,2,1,12,255,14,

Python/opcode_targets.h

@@ -29,11 +29,11 @@ static void *opcode_targets[256] = {
     &&TARGET_BINARY_TRUE_DIVIDE,
     &&TARGET_INPLACE_FLOOR_DIVIDE,
     &&TARGET_INPLACE_TRUE_DIVIDE,
-    &&_unknown_opcode,
+    &&TARGET_GET_LEN,
-    &&_unknown_opcode,
+    &&TARGET_MATCH_MAPPING,
-    &&_unknown_opcode,
+    &&TARGET_MATCH_SEQUENCE,
-    &&_unknown_opcode,
+    &&TARGET_MATCH_KEYS,
-    &&_unknown_opcode,
+    &&TARGET_COPY_DICT_WITHOUT_KEYS,
     &&_unknown_opcode,
     &&_unknown_opcode,
     &&_unknown_opcode,
@@ -151,7 +151,7 @@ static void *opcode_targets[256] = {
     &&_unknown_opcode,
     &&_unknown_opcode,
     &&_unknown_opcode,
-    &&_unknown_opcode,
+    &&TARGET_MATCH_CLASS,
     &&_unknown_opcode,
     &&TARGET_SETUP_ASYNC_WITH,
     &&TARGET_FORMAT_VALUE,

Python/pystate.c

@@ -308,6 +308,8 @@ interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
     Py_CLEAR(interp->importlib);
     Py_CLEAR(interp->import_func);
     Py_CLEAR(interp->dict);
+    Py_CLEAR(interp->map_abc);
+    Py_CLEAR(interp->seq_abc);
 #ifdef HAVE_FORK
     Py_CLEAR(interp->before_forkers);
     Py_CLEAR(interp->after_forkers_parent);

Python/symtable.c

@@ -207,6 +207,7 @@ static int symtable_visit_argannotations(struct symtable *st, asdl_arg_seq *args
 static int symtable_implicit_arg(struct symtable *st, int pos);
 static int symtable_visit_annotations(struct symtable *st, arguments_ty, expr_ty);
 static int symtable_visit_withitem(struct symtable *st, withitem_ty item);
+static int symtable_visit_match_case(struct symtable *st, match_case_ty m);
 
 
 static identifier top = NULL, lambda = NULL, genexpr = NULL,
@@ -239,6 +240,7 @@ symtable_new(void)
         goto fail;
     st->st_cur = NULL;
     st->st_private = NULL;
+    st->in_pattern = 0;
     return st;
  fail:
     PySymtable_Free(st);
@@ -1294,6 +1296,10 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         if (s->v.If.orelse)
             VISIT_SEQ(st, stmt, s->v.If.orelse);
         break;
+    case Match_kind:
+        VISIT(st, expr, s->v.Match.subject);
+        VISIT_SEQ(st, match_case, s->v.Match.cases);
+        break;
     case Raise_kind:
         if (s->v.Raise.exc) {
             VISIT(st, expr, s->v.Raise.exc);
@@ -1648,6 +1654,13 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
             VISIT(st, expr, e->v.Slice.step)
         break;
     case Name_kind:
+        // Don't make "_" a local when used in a pattern:
+        if (st->in_pattern &&
+            e->v.Name.ctx == Store &&
+            _PyUnicode_EqualToASCIIString(e->v.Name.id, "_"))
+        {
+            break;
+        }
         if (!symtable_add_def(st, e->v.Name.id,
                               e->v.Name.ctx == Load ? USE : DEF_LOCAL))
             VISIT_QUIT(st, 0);
@@ -1667,6 +1680,13 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
     case Tuple_kind:
         VISIT_SEQ(st, expr, e->v.Tuple.elts);
         break;
+    case MatchAs_kind:
+        VISIT(st, expr, e->v.MatchAs.pattern);
+        symtable_add_def(st, e->v.MatchAs.name, DEF_LOCAL);
+        break;
+    case MatchOr_kind:
+        VISIT_SEQ(st, expr, e->v.MatchOr.patterns);
+        break;
     }
     VISIT_QUIT(st, 1);
 }
@@ -1785,6 +1805,20 @@ symtable_visit_withitem(struct symtable *st, withitem_ty item)
     return 1;
 }
 
+static int
+symtable_visit_match_case(struct symtable *st, match_case_ty m)
+{
+    assert(!st->in_pattern);
+    st->in_pattern = 1;
+    VISIT(st, expr, m->pattern);
+    assert(st->in_pattern);
+    st->in_pattern = 0;
+    if (m->guard) {
+        VISIT(st, expr, m->guard);
+    }
+    VISIT_SEQ(st, stmt, m->body);
+    return 1;
+}
 
 static int
 symtable_visit_alias(struct symtable *st, alias_ty a)