Fix unintentionally swapped words in index.md (#3809)

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

diff --git a/src/blib2to3/Grammar.txt b/src/blib2to3/Grammar.txt
index eafaee84cb36157ae7fee6763d62031858ad63a9..e48e66363fb504f2430d2ec61553e122fbd52ffc 100644 (file)
--- a/src/blib2to3/Grammar.txt
+++ b/src/blib2to3/Grammar.txt
@@ -12,11 +12,17 @@ file_input: (NEWLINE | stmt)* ENDMARKER
 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
 eval_input: testlist NEWLINE* ENDMARKER
 
 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
 eval_input: testlist NEWLINE* ENDMARKER
 

+typevar: NAME [':' expr]
+paramspec: '**' NAME
+typevartuple: '*' NAME
+typeparam: typevar | paramspec | typevartuple
+typeparams: '[' typeparam (',' typeparam)* [','] ']'
+

 decorator: '@' namedexpr_test NEWLINE
 decorators: decorator+
 decorated: decorators (classdef | funcdef | async_funcdef)
 async_funcdef: ASYNC funcdef
 decorator: '@' namedexpr_test NEWLINE
 decorators: decorator+
 decorated: decorators (classdef | funcdef | async_funcdef)
 async_funcdef: ASYNC funcdef

-funcdef: 'def' NAME parameters ['->' test] ':' suite
+funcdef: 'def' NAME [typeparams] parameters ['->' test] ':' suite

 parameters: '(' [typedargslist] ')'
 
 # The following definition for typedarglist is equivalent to this set of rules:
 parameters: '(' [typedargslist] ')'
 
 # The following definition for typedarglist is equivalent to this set of rules:


@@ -24,7 +30,7 @@ parameters: '(' [typedargslist] ')'
 #     arguments = argument (',' argument)*
 #     argument = tfpdef ['=' test]
 #     kwargs = '**' tname [',']
 #     arguments = argument (',' argument)*
 #     argument = tfpdef ['=' test]
 #     kwargs = '**' tname [',']

-#     args = '*' [tname]
+#     args = '*' [tname_star]

 #     kwonly_kwargs = (',' argument)* [',' [kwargs]]
 #     args_kwonly_kwargs = args kwonly_kwargs | kwargs
 #     poskeyword_args_kwonly_kwargs = arguments [',' [args_kwonly_kwargs]]
 #     kwonly_kwargs = (',' argument)* [',' [kwargs]]
 #     args_kwonly_kwargs = args kwonly_kwargs | kwargs
 #     poskeyword_args_kwonly_kwargs = arguments [',' [args_kwonly_kwargs]]


@@ -34,14 +40,15 @@ parameters: '(' [typedargslist] ')'
 # It needs to be fully expanded to allow our LL(1) parser to work on it.
 
 typedargslist: tfpdef ['=' test] (',' tfpdef ['=' test])* ',' '/' [
 # 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])*
+                     ',' [((tfpdef ['=' test] ',')* ('*' [tname_star] (',' tname ['=' test])*

                             [',' ['**' tname [',']]] | '**' tname [','])
                      | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])]
                             [',' ['**' tname [',']]] | '**' tname [','])
                      | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])]

-                ] | ((tfpdef ['=' test] ',')* ('*' [tname] (',' tname ['=' test])*
+                ] | ((tfpdef ['=' test] ',')* ('*' [tname_star] (',' tname ['=' test])*

                      [',' ['**' tname [',']]] | '**' tname [','])
                      | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
 
 tname: NAME [':' test]
                      [',' ['**' tname [',']]] | '**' tname [','])
                      | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
 
 tname: NAME [':' test]

+tname_star: NAME [':' (test|star_expr)]

 tfpdef: tname | '(' tfplist ')'
 tfplist: tfpdef (',' tfpdef)* [',']
 
 tfpdef: tname | '(' tfplist ')'
 tfplist: tfpdef (',' tfpdef)* [',']
 


@@ -73,11 +80,11 @@ vfplist: vfpdef (',' vfpdef)* [',']
 
 stmt: simple_stmt | compound_stmt
 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
 
 stmt: simple_stmt | compound_stmt
 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE

-small_stmt: (expr_stmt | print_stmt  | del_stmt | pass_stmt | flow_stmt |
+small_stmt: (type_stmt | expr_stmt | print_stmt  | del_stmt | pass_stmt | flow_stmt |

              import_stmt | global_stmt | exec_stmt | assert_stmt)
 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                      ('=' (yield_expr|testlist_star_expr))*)
              import_stmt | global_stmt | exec_stmt | assert_stmt)
 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                      ('=' (yield_expr|testlist_star_expr))*)

-annassign: ':' test ['=' test]
+annassign: ':' test ['=' (yield_expr|testlist_star_expr)]

 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
             '<<=' | '>>=' | '**=' | '//=')
 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
             '<<=' | '>>=' | '**=' | '//=')


@@ -104,22 +111,22 @@ dotted_name: NAME ('.' NAME)*
 global_stmt: ('global' | 'nonlocal') NAME (',' NAME)*
 exec_stmt: 'exec' expr ['in' test [',' test]]
 assert_stmt: 'assert' test [',' test]
 global_stmt: ('global' | 'nonlocal') NAME (',' NAME)*
 exec_stmt: 'exec' expr ['in' test [',' test]]
 assert_stmt: 'assert' test [',' test]

+type_stmt: "type" NAME [typeparams] '=' expr

 
 

-compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt
+compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt | match_stmt

 async_stmt: ASYNC (funcdef | with_stmt | for_stmt)
 if_stmt: 'if' namedexpr_test ':' suite ('elif' namedexpr_test ':' suite)* ['else' ':' suite]
 while_stmt: 'while' namedexpr_test ':' suite ['else' ':' suite]
 async_stmt: ASYNC (funcdef | with_stmt | for_stmt)
 if_stmt: 'if' namedexpr_test ':' suite ('elif' namedexpr_test ':' suite)* ['else' ':' suite]
 while_stmt: 'while' namedexpr_test ':' suite ['else' ':' suite]

-for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
+for_stmt: 'for' exprlist 'in' testlist_star_expr ':' suite ['else' ':' suite]

 try_stmt: ('try' ':' suite
            ((except_clause ':' suite)+
            ['else' ':' suite]
            ['finally' ':' suite] |
           'finally' ':' suite))
 try_stmt: ('try' ':' suite
            ((except_clause ':' suite)+
            ['else' ':' suite]
            ['finally' ':' suite] |
           'finally' ':' suite))

-with_stmt: 'with' with_item (',' with_item)*  ':' suite
-with_item: test ['as' expr]
-with_var: 'as' expr
+with_stmt: 'with' asexpr_test (',' asexpr_test)*  ':' suite
+

 # NB compile.c makes sure that the default except clause is last
 # NB compile.c makes sure that the default except clause is last

-except_clause: 'except' [test [(',' | 'as') test]]
+except_clause: 'except' ['*'] [test [(',' | 'as') test]]

 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
 
 # Backward compatibility cruft to support:
 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
 
 # Backward compatibility cruft to support:


@@ -131,7 +138,15 @@ testlist_safe: old_test [(',' old_test)+ [',']]
 old_test: or_test | old_lambdef
 old_lambdef: 'lambda' [varargslist] ':' old_test
 
 old_test: or_test | old_lambdef
 old_lambdef: 'lambda' [varargslist] ':' old_test
 

-namedexpr_test: test [':=' test]
+namedexpr_test: asexpr_test [':=' asexpr_test]
+
+# This is actually not a real rule, though since the parser is very
+# limited in terms of the strategy about match/case rules, we are inserting
+# a virtual case (<expr> as <expr>) as a valid expression. Unless a better
+# approach is thought, the only side effect of this seem to be just allowing
+# more stuff to be parser (which would fail on the ast).
+asexpr_test: test ['as' test]
+

 test: or_test ['if' or_test 'else' test] | lambdef
 or_test: and_test ('or' and_test)*
 and_test: not_test ('and' not_test)*
 test: or_test ['if' or_test 'else' test] | lambdef
 or_test: and_test ('or' and_test)*
 and_test: not_test ('and' not_test)*


@@ -156,17 +171,17 @@ listmaker: (namedexpr_test|star_expr) ( old_comp_for | (',' (namedexpr_test|star
 testlist_gexp: (namedexpr_test|star_expr) ( old_comp_for | (',' (namedexpr_test|star_expr))* [','] )
 lambdef: 'lambda' [varargslist] ':' test
 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
 testlist_gexp: (namedexpr_test|star_expr) ( old_comp_for | (',' (namedexpr_test|star_expr))* [','] )
 lambdef: 'lambda' [varargslist] ':' test
 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME

-subscriptlist: subscript (',' subscript)* [',']
-subscript: test | [test] ':' [test] [sliceop]
+subscriptlist: (subscript|star_expr) (',' (subscript|star_expr))* [',']
+subscript: test [':=' test] | [test] ':' [test] [sliceop]

 sliceop: ':' [test]
 exprlist: (expr|star_expr) (',' (expr|star_expr))* [',']
 testlist: test (',' test)* [',']
 sliceop: ':' [test]
 exprlist: (expr|star_expr) (',' (expr|star_expr))* [',']
 testlist: test (',' test)* [',']

-dictsetmaker: ( ((test ':' test | '**' expr)
-                 (comp_for | (',' (test ':' test | '**' expr))* [','])) |
-                ((test | star_expr)
-                (comp_for | (',' (test | star_expr))* [','])) )
+dictsetmaker: ( ((test ':' asexpr_test | '**' expr)
+                 (comp_for | (',' (test ':' asexpr_test | '**' expr))* [','])) |
+                ((test [':=' test] | star_expr)
+                (comp_for | (',' (test [':=' test] | star_expr))* [','])) )

 
 

-classdef: 'class' NAME ['(' [arglist] ')'] ':' suite
+classdef: 'class' NAME [typeparams] ['(' [arglist] ')'] ':' suite

 
 arglist: argument (',' argument)* [',']
 
 
 arglist: argument (',' argument)* [',']
 


@@ -178,8 +193,9 @@ arglist: argument (',' argument)* [',']
 # multiple (test comp_for) arguments are blocked; keyword unpackings
 # that precede iterable unpackings are blocked; etc.
 argument: ( test [comp_for] |
 # 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 [comp_for] |
+            test 'as' test |
+            test '=' asexpr_test |

            '**' test |
             '*' test )
 
            '**' test |
             '*' test )
 


@@ -213,3 +229,31 @@ encoding_decl: NAME
 
 yield_expr: 'yield' [yield_arg]
 yield_arg: 'from' test | testlist_star_expr
 
 yield_expr: 'yield' [yield_arg]
 yield_arg: 'from' test | testlist_star_expr

+
+
+# 3.10 match statement definition
+
+# PS: normally the grammar is much much more restricted, but
+# at this moment for not trying to bother much with encoding the
+# exact same DSL in a LL(1) parser, we will just accept an expression
+# and let the ast.parse() step of the safe mode to reject invalid
+# grammar.
+
+# The reason why it is more restricted is that, patterns are some
+# sort of a DSL (more advanced than our LHS on assignments, but
+# still in a very limited python subset). They are not really
+# expressions, but who cares. If we can parse them, that is enough
+# to reformat them.
+
+match_stmt: "match" subject_expr ':' NEWLINE INDENT case_block+ DEDENT
+
+# 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
+guard: 'if' namedexpr_test
+patterns: pattern (',' pattern)* [',']
+pattern: (expr|star_expr) ['as' expr]