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-rw-r--r--Lib/lib2to3/Grammar.txt10
-rw-r--r--Lib/lib2to3/pgen2/grammar.py1
-rwxr-xr-xLib/lib2to3/pgen2/token.py3
-rw-r--r--Lib/lib2to3/pgen2/tokenize.py2
-rw-r--r--Lib/lib2to3/tests/test_parser.py15
-rw-r--r--Misc/NEWS.d/next/Library/2019-06-18-19-38-27.bpo-36541.XI8mi1.rst2
6 files changed, 27 insertions, 6 deletions
diff --git a/Lib/lib2to3/Grammar.txt b/Lib/lib2to3/Grammar.txt
index 51f5820..e007dc1 100644
--- a/Lib/lib2to3/Grammar.txt
+++ b/Lib/lib2to3/Grammar.txt
@@ -67,8 +67,8 @@ 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]
-while_stmt: 'while' test ':' suite ['else' ':' suite]
+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]
try_stmt: ('try' ':' suite
((except_clause ':' suite)+
@@ -91,6 +91,7 @@ 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 +112,8 @@ atom: ('(' [yield_expr|testlist_gexp] ')' |
'{' [dictsetmaker] '}' |
'`' testlist1 '`' |
NAME | NUMBER | STRING+ | '.' '.' '.')
-listmaker: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] )
-testlist_gexp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] )
+listmaker: (namedexpr_test|star_expr) ( comp_for | (',' (namedexpr_test|star_expr))* [','] )
+testlist_gexp: (namedexpr_test|star_expr) ( comp_for | (',' (namedexpr_test|star_expr))* [','] )
lambdef: 'lambda' [varargslist] ':' test
trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
subscriptlist: subscript (',' subscript)* [',']
@@ -137,6 +138,7 @@ 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 )
diff --git a/Lib/lib2to3/pgen2/grammar.py b/Lib/lib2to3/pgen2/grammar.py
index a1da546..6a4d575 100644
--- a/Lib/lib2to3/pgen2/grammar.py
+++ b/Lib/lib2to3/pgen2/grammar.py
@@ -178,6 +178,7 @@ opmap_raw = """
// DOUBLESLASH
//= DOUBLESLASHEQUAL
-> RARROW
+:= COLONEQUAL
"""
opmap = {}
diff --git a/Lib/lib2to3/pgen2/token.py b/Lib/lib2to3/pgen2/token.py
index 1a67955..5f6612f 100755
--- a/Lib/lib2to3/pgen2/token.py
+++ b/Lib/lib2to3/pgen2/token.py
@@ -65,7 +65,8 @@ RARROW = 55
AWAIT = 56
ASYNC = 57
ERRORTOKEN = 58
-N_TOKENS = 59
+COLONEQUAL = 59
+N_TOKENS = 60
NT_OFFSET = 256
#--end constants--
diff --git a/Lib/lib2to3/pgen2/tokenize.py b/Lib/lib2to3/pgen2/tokenize.py
index 7924ff3..0e2685d 100644
--- a/Lib/lib2to3/pgen2/tokenize.py
+++ b/Lib/lib2to3/pgen2/tokenize.py
@@ -93,7 +93,7 @@ Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"<>", r"!=",
r"~")
Bracket = '[][(){}]'
-Special = group(r'\r?\n', r'[:;.,`@]')
+Special = group(r'\r?\n', r':=', r'[:;.,`@]')
Funny = group(Operator, Bracket, Special)
PlainToken = group(Number, Funny, String, Name)
diff --git a/Lib/lib2to3/tests/test_parser.py b/Lib/lib2to3/tests/test_parser.py
index a0c31e8..ba2bb78 100644
--- a/Lib/lib2to3/tests/test_parser.py
+++ b/Lib/lib2to3/tests/test_parser.py
@@ -629,6 +629,21 @@ class TestLiterals(GrammarTest):
self.validate(s)
+class TestNamedAssignments(GrammarTest):
+
+ def test_named_assignment_if(self):
+ driver.parse_string("if f := x(): pass\n")
+
+ def test_named_assignment_while(self):
+ driver.parse_string("while f := x(): pass\n")
+
+ def test_named_assignment_generator(self):
+ driver.parse_string("any((lastNum := num) == 1 for num in [1, 2, 3])\n")
+
+ def test_named_assignment_listcomp(self):
+ driver.parse_string("[(lastNum := num) == 1 for num in [1, 2, 3]]\n")
+
+
class TestPickleableException(unittest.TestCase):
def test_ParseError(self):
err = ParseError('msg', 2, None, (1, 'context'))
diff --git a/Misc/NEWS.d/next/Library/2019-06-18-19-38-27.bpo-36541.XI8mi1.rst b/Misc/NEWS.d/next/Library/2019-06-18-19-38-27.bpo-36541.XI8mi1.rst
new file mode 100644
index 0000000..e7b9dd6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-06-18-19-38-27.bpo-36541.XI8mi1.rst
@@ -0,0 +1,2 @@
+lib2to3 now recognizes named assignment expressions (the walrus operator,
+``:=``)