X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/4d03716eaea58ee38d77cf2bba0a72b7a27ec9fa..25d886f52c2bbbb58386ac8050f4e67952507bc7:/src/blib2to3/Grammar.txt
diff --git a/src/blib2to3/Grammar.txt b/src/blib2to3/Grammar.txt
index 69b9af9..bd8a452 100644
--- a/src/blib2to3/Grammar.txt
+++ b/src/blib2to3/Grammar.txt
@@ -24,7 +24,7 @@ parameters: '(' [typedargslist] ')'
# 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]]
@@ -34,14 +34,15 @@ parameters: '(' [typedargslist] ')'
# 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])* [','])]
- ] | ((tfpdef ['=' test] ',')* ('*' [tname] (',' tname ['=' test])*
+ ] | ((tfpdef ['=' test] ',')* ('*' [tname_star] (',' tname ['=' test])*
[',' ['**' tname [',']]] | '**' tname [','])
| tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
tname: NAME [':' test]
+tname_star: NAME [':' (test|star_expr)]
tfpdef: tname | '(' tfplist ')'
tfplist: tfpdef (',' tfpdef)* [',']
@@ -105,21 +106,20 @@ global_stmt: ('global' | 'nonlocal') NAME (',' NAME)*
exec_stmt: 'exec' expr ['in' test [',' test]]
assert_stmt: 'assert' test [',' test]
-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]
-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))
-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
-except_clause: 'except' [test [(',' | 'as') test]]
+except_clause: 'except' ['*'] [test [(',' | 'as') test]]
suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
# Backward compatibility cruft to support:
@@ -131,7 +131,15 @@ testlist_safe: old_test [(',' 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)*
@@ -156,15 +164,15 @@ 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
-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)* [',']
-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
@@ -178,8 +186,9 @@ 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 [comp_for] |
+ test 'as' test |
+ test '=' asexpr_test |
'**' test |
'*' test )
@@ -213,3 +222,31 @@ encoding_decl: NAME
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]