python · emilyemorehouse · Jan 24, 2019 · Jul 21, 2018 · Jul 22, 2018 · Jul 22, 2018
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
@@ -800,6 +800,7 @@ the variables:
   single: PyExc_SystemError
   single: PyExc_SystemExit
   single: PyExc_TabError
+   single: PyExc_TargetScopeError
   single: PyExc_TimeoutError
   single: PyExc_TypeError
   single: PyExc_UnboundLocalError
@@ -901,6 +902,8 @@ the variables:
 +-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_TabError`                | :exc:`TabError`                 |          |
 +-----------------------------------------+---------------------------------+----------+
+| :c:data:`PyExc_TargetScopeError`        | :exc:`TargetScopeError`         |          |
+-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_TimeoutError`            | :exc:`TimeoutError`             |          |
 +-----------------------------------------+---------------------------------+----------+
 | :c:data:`PyExc_TypeError`               | :exc:`TypeError`                |          |

diff --git a/Doc/library/token-list.inc b/Doc/library/token-list.inc
diff --git a/Grammar/Grammar b/Grammar/Grammar
@@ -69,7 +69,7 @@ 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
@@ -83,6 +83,7 @@ with_item: test ['as' expr]
 except_clause: 'except' [test ['as' NAME]]
 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT

+namedexpr_test: test [':=' test]
 test: or_test ['if' or_test 'else' test] | lambdef
 test_nocond: or_test | lambdef_nocond
 lambdef: 'lambda' [varargslist] ':' test
@@ -108,7 +109,7 @@ atom: ('(' [yield_expr|testlist_comp] ')' |
       '[' [testlist_comp] ']' |
       '{' [dictorsetmaker] '}' |
       NAME | NUMBER | STRING+ | '...' | 'None' | 'True' | 'False')
-testlist_comp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] )
+testlist_comp: (namedexpr_test|star_expr) ( comp_for | (',' (namedexpr_test|star_expr))* [','] )
 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
 subscriptlist: subscript (',' subscript)* [',']
 subscript: test | [test] ':' [test] [sliceop]
@@ -134,6 +135,7 @@ 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/Grammar/Tokens b/Grammar/Tokens
@@ -52,6 +52,7 @@ AT                      '@'
 ATEQUAL                 '@='
 RARROW                  '->'
 ELLIPSIS                '...'
+COLONEQUAL              ':='

 OP
 ERRORTOKEN

diff --git a/Include/Python-ast.h b/Include/Python-ast.h
diff --git a/Include/graminit.h b/Include/graminit.h
diff --git a/Include/pyerrors.h b/Include/pyerrors.h
@@ -108,6 +108,7 @@ PyAPI_DATA(PyObject *) PyExc_NotImplementedError;
 PyAPI_DATA(PyObject *) PyExc_SyntaxError;
 PyAPI_DATA(PyObject *) PyExc_IndentationError;
 PyAPI_DATA(PyObject *) PyExc_TabError;
+PyAPI_DATA(PyObject *) PyExc_TargetScopeError;
 PyAPI_DATA(PyObject *) PyExc_ReferenceError;
 PyAPI_DATA(PyObject *) PyExc_SystemError;
 PyAPI_DATA(PyObject *) PyExc_SystemExit;

diff --git a/Include/symtable.h b/Include/symtable.h
@@ -50,6 +50,7 @@ typedef struct _symtable_entry {
                                     including free refs to globals */
    unsigned ste_generator : 1;   /* true if namespace is a generator */
    unsigned ste_coroutine : 1;   /* true if namespace is a coroutine */
+    unsigned ste_comprehension : 1; /* true if namespace is a list comprehension */
    unsigned ste_varargs : 1;     /* true if block has varargs */
    unsigned ste_varkeywords : 1; /* true if block has varkeywords */
    unsigned ste_returns_value : 1;  /* true if namespace uses return with

diff --git a/Include/token.h b/Include/token.h
diff --git a/Lib/_compat_pickle.py b/Lib/_compat_pickle.py
@@ -128,6 +128,7 @@
    "SystemError",
    "SystemExit",
    "TabError",
+    "TargetScopeError",
    "TypeError",
    "UnboundLocalError",
    "UnicodeDecodeError",

diff --git a/Lib/symbol.py b/Lib/symbol.py
@@ -61,44 +61,45 @@
 with_item = 302
 except_clause = 303
 suite = 304
-test = 305
-test_nocond = 306
-lambdef = 307
-lambdef_nocond = 308
-or_test = 309
-and_test = 310
-not_test = 311
-comparison = 312
-comp_op = 313
-star_expr = 314
-expr = 315
-xor_expr = 316
-and_expr = 317
-shift_expr = 318
-arith_expr = 319
-term = 320
-factor = 321
-power = 322
-atom_expr = 323
-atom = 324
-testlist_comp = 325
-trailer = 326
-subscriptlist = 327
-subscript = 328
-sliceop = 329
-exprlist = 330
-testlist = 331
-dictorsetmaker = 332
-classdef = 333
-arglist = 334
-argument = 335
-comp_iter = 336
-sync_comp_for = 337
-comp_for = 338
-comp_if = 339
-encoding_decl = 340
-yield_expr = 341
-yield_arg = 342
+namedexpr_test = 305
+test = 306
+test_nocond = 307
+lambdef = 308
+lambdef_nocond = 309
+or_test = 310
+and_test = 311
+not_test = 312
+comparison = 313
+comp_op = 314
+star_expr = 315
+expr = 316
+xor_expr = 317
+and_expr = 318
+shift_expr = 319
+arith_expr = 320
+term = 321
+factor = 322
+power = 323
+atom_expr = 324
+atom = 325
+testlist_comp = 326
+trailer = 327
+subscriptlist = 328
+subscript = 329
+sliceop = 330
+exprlist = 331
+testlist = 332
+dictorsetmaker = 333
+classdef = 334
+arglist = 335
+argument = 336
+comp_iter = 337
+sync_comp_for = 338
+comp_for = 339
+comp_if = 340
+encoding_decl = 341
+yield_expr = 342
+yield_arg = 343
 #--end constants--

 sym_name = {}

diff --git a/Lib/test/exception_hierarchy.txt b/Lib/test/exception_hierarchy.txt
@@ -42,6 +42,7 @@ BaseException
      |    +-- NotImplementedError
      |    +-- RecursionError
      +-- SyntaxError
+      |    +-- TargetScopeError
      |    +-- IndentationError
      |         +-- TabError
      +-- SystemError