Allow top-level starred expression on match (#2659)

Fixes #2647

diff --git a/CHANGES.md b/CHANGES.md
index 57af2c5deae0d6d8ec633969a074c0823b4b11cc..4a8ee0e692c329313ab161b00e03126f35b812a9 100644 (file)
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,7 +8,8 @@
   cell magics were tokenized, leading to possible indentation errors e.g. with
   `%%writefile`. (#2630)
 - Fixed Python 3.10 support on platforms without ProcessPoolExecutor (#2631)
   cell magics were tokenized, leading to possible indentation errors e.g. with
   `%%writefile`. (#2630)
 - Fixed Python 3.10 support on platforms without ProcessPoolExecutor (#2631)

-- Fixed `match` statements with open sequence subjects, like `match a, b:` (#2639)
+- Fixed `match` statements with open sequence subjects, like `match a, b:` or
+  `match a, *b:` (#2639) (#2659)

 - Fixed assignment to environment variables in Jupyter Notebooks (#2642)
 - Add `flake8-simplify` and `flake8-comprehensions` plugins (#2653)
 
 - Fixed assignment to environment variables in Jupyter Notebooks (#2642)
 - Add `flake8-simplify` and `flake8-comprehensions` plugins (#2653)
 

diff --git a/src/blib2to3/Grammar.txt b/src/blib2to3/Grammar.txt
index de9a6a2283fe3a26bde755cbd765a989b0b47180..c3001e810652f7c28ed78f679854d3aeb6d9f15b 100644 (file)
--- a/src/blib2to3/Grammar.txt
+++ b/src/blib2to3/Grammar.txt
@@ -238,7 +238,11 @@ yield_arg: 'from' test | testlist_star_expr
 # to reformat them.
 
 match_stmt: "match" subject_expr ':' NEWLINE INDENT case_block+ DEDENT
 # to reformat them.
 
 match_stmt: "match" subject_expr ':' NEWLINE INDENT case_block+ DEDENT

-subject_expr: namedexpr_test (',' namedexpr_test)* [',']
+
+# This is more permissive than the actual version. For example it
+# accepts `match *something:`, even though single-item starred expressions
+# are forbidden.
+subject_expr: (namedexpr_test|star_expr) (',' (namedexpr_test|star_expr))* [',']

 
 # cases
 case_block: "case" patterns [guard] ':' suite
 
 # cases
 case_block: "case" patterns [guard] ':' suite

diff --git a/tests/data/pattern_matching_extras.py b/tests/data/pattern_matching_extras.py
index d4bba38ee7cd35f21f086c4c89936a8039a6bc60..706148561a272fc57ae44933abf8d0cea6123468 100644 (file)
--- a/tests/data/pattern_matching_extras.py
+++ b/tests/data/pattern_matching_extras.py
@@ -43,3 +43,10 @@ match more := (than, one), indeed,:
         pass
     case _:
         pass
         pass
     case _:
         pass

+
+
+match a, *b, c:
+    case [*_]:
+        return "seq"
+    case {}:
+        return "map"