[3.9] bpo-42381: Allow walrus in set literals and set comprehensions (GH-23332) (GH-23333)
Currently walruses are not allowerd in set literals and set comprehensions:
>>> {y := 4, 4**2, 3**3}
File "<stdin>", line 1
{y := 4, 4**2, 3**3}
^
SyntaxError: invalid syntax
but they should be allowed as well per PEP 572.
(cherry picked from commit b0aba1fcdc3da952698d99aec2334faa79a8b68c)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>diff --git a/Grammar/python.gram b/Grammar/python.gram
index 257d2f5..ce78397 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -301,7 +301,6 @@
| simple_stmt
| invalid_block
-expressions_list[asdl_seq*]: a=','.star_expression+ [','] { a }
star_expressions[expr_ty]:
| a=star_expression b=(',' c=star_expression { c })+ [','] {
_Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
@@ -505,9 +504,9 @@
genexp[expr_ty]:
| '(' a=named_expression ~ b=for_if_clauses ')' { _Py_GeneratorExp(a, b, EXTRA) }
| invalid_comprehension
-set[expr_ty]: '{' a=expressions_list '}' { _Py_Set(a, EXTRA) }
+set[expr_ty]: '{' a=star_named_expressions '}' { _Py_Set(a, EXTRA) }
setcomp[expr_ty]:
- | '{' a=expression ~ b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
+ | '{' a=named_expression ~ b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
| invalid_comprehension
dict[expr_ty]:
| '{' a=[double_starred_kvpairs] '}' {