Fix unstable formatting involving unwrapping multiple parentheses (#836) (#961)

[etc/vim.git] / blib2to3 / Grammar.txt

diff --git a/blib2to3/Grammar.txt b/blib2to3/Grammar.txt
index c9cb3a7e8c9bfe159684f3e23afaad8a2cb9a2d0..daecb15e936a2d3236e5ac45f3d22c05a0869812 100644 (file)
--- a/blib2to3/Grammar.txt
+++ b/blib2to3/Grammar.txt
@@ -18,15 +18,55 @@ decorated: decorators (classdef | funcdef | async_funcdef)
 async_funcdef: ASYNC funcdef
 funcdef: 'def' NAME parameters ['->' test] ':' suite
 parameters: '(' [typedargslist] ')'
-typedargslist: ((tfpdef ['=' test] ',')*
-                ('*' [tname] (',' tname ['=' test])* [',' ['**' tname [',']]] | '**' tname [','])
-                | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
+
+# The following definition for typedarglist is equivalent to this set of rules:
+#
+#     arguments = argument (',' argument)*
+#     argument = tfpdef ['=' test]
+#     kwargs = '**' tname [',']
+#     args = '*' [tname]
+#     kwonly_kwargs = (',' argument)* [',' [kwargs]]
+#     args_kwonly_kwargs = args kwonly_kwargs | kwargs
+#     poskeyword_args_kwonly_kwargs = arguments [',' [args_kwonly_kwargs]]
+#     typedargslist_no_posonly  = poskeyword_args_kwonly_kwargs | args_kwonly_kwargs
+#     typedarglist = arguments ',' '/' [',' [typedargslist_no_posonly]])|(typedargslist_no_posonly)"
+#
+# It needs to be fully expanded to allow our LL(1) parser to work on it.
+
+typedargslist: tfpdef ['=' test] (',' tfpdef ['=' test])* ',' '/' [
+                     ',' [((tfpdef ['=' test] ',')* ('*' [tname] (',' tname ['=' test])*
+                            [',' ['**' tname [',']]] | '**' tname [','])
+                     | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])]
+                ] | ((tfpdef ['=' test] ',')* ('*' [tname] (',' tname ['=' test])*
+                     [',' ['**' tname [',']]] | '**' tname [','])
+                     | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
+
 tname: NAME [':' test]
 tfpdef: tname | '(' tfplist ')'
 tfplist: tfpdef (',' tfpdef)* [',']
-varargslist: ((vfpdef ['=' test] ',')*
-              ('*' [vname] (',' vname ['=' test])*  [',' ['**' vname [',']]] | '**' vname [','])
-              | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
+
+# The following definition for varargslist is equivalent to this set of rules:
+#
+#     arguments = argument (',' argument )*
+#     argument = vfpdef ['=' test]
+#     kwargs = '**' vname [',']
+#     args = '*' [vname]
+#     kwonly_kwargs = (',' argument )* [',' [kwargs]]
+#     args_kwonly_kwargs = args kwonly_kwargs | kwargs
+#     poskeyword_args_kwonly_kwargs = arguments [',' [args_kwonly_kwargs]]
+#     vararglist_no_posonly = poskeyword_args_kwonly_kwargs | args_kwonly_kwargs
+#     varargslist = arguments ',' '/' [','[(vararglist_no_posonly)]] | (vararglist_no_posonly)
+#
+# It needs to be fully expanded to allow our LL(1) parser to work on it.
+
+varargslist: vfpdef ['=' test ](',' vfpdef ['=' test])* ',' '/' [',' [
+                     ((vfpdef ['=' test] ',')* ('*' [vname] (',' vname ['=' test])*
+                            [',' ['**' vname [',']]] | '**' vname [','])
+                            | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
+                     ]] | ((vfpdef ['=' test] ',')*
+                     ('*' [vname] (',' vname ['=' test])*  [',' ['**' vname [',']]]| '**' vname [','])
+                     | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
+
 vname: NAME
 vfpdef: vname | '(' vfplist ')'
 vfplist: vfpdef (',' vfpdef)* [',']
@@ -67,7 +107,7 @@ assert_stmt: 'assert' test [',' test]
 
 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt
 async_stmt: ASYNC (funcdef | with_stmt | for_stmt)
-if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
+if_stmt: 'if' namedexpr_test ':' suite ('elif' namedexpr_test ':' suite)* ['else' ':' suite]
 while_stmt: 'while' test ':' suite ['else' ':' suite]
 for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
 try_stmt: ('try' ':' suite
@@ -91,6 +131,7 @@ testlist_safe: old_test [(',' old_test)+ [',']]
 old_test: or_test | old_lambdef
 old_lambdef: 'lambda' [varargslist] ':' old_test
 
+namedexpr_test: test [':=' test]
 test: or_test ['if' or_test 'else' test] | lambdef
 or_test: and_test ('or' and_test)*
 and_test: not_test ('and' not_test)*
@@ -111,8 +152,8 @@ atom: ('(' [yield_expr|testlist_gexp] ')' |
        '{' [dictsetmaker] '}' |
        '`' testlist1 '`' |
        NAME | NUMBER | STRING+ | '.' '.' '.')
-listmaker: (test|star_expr) ( old_comp_for | (',' (test|star_expr))* [','] )
-testlist_gexp: (test|star_expr) ( old_comp_for | (',' (test|star_expr))* [','] )
+listmaker: (namedexpr_test|star_expr) ( old_comp_for | (',' (namedexpr_test|star_expr))* [','] )
+testlist_gexp: (namedexpr_test|star_expr) ( old_comp_for | (',' (namedexpr_test|star_expr))* [','] )
 lambdef: 'lambda' [varargslist] ':' test
 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
 subscriptlist: subscript (',' subscript)* [',']
@@ -137,6 +178,7 @@ arglist: argument (',' argument)* [',']
 # multiple (test comp_for) arguments are blocked; keyword unpackings
 # that precede iterable unpackings are blocked; etc.
 argument: ( test [comp_for] |
+            test ':=' test |
             test '=' test |
            '**' test |
             '*' test )