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

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Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Talin <viridia@gmail.com>
Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
This commit is contained in:
Brandt Bucher 2021-02-26 14:51:55 -08:00 • committed by GitHub
parent cc02b4f2e8
commit 145bf269df
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43 changed files with 10867 additions and 2607 deletions
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@ -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)