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| author | Tim Hatch <tim@timhatch.com> | 2020-04-02 22:34:54 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-04-02 22:34:54 (GMT) |
| commit | 3c3aa4516c70753de06bb142b6793d01330fcf0f (patch) | |
| tree | cea6e6cc2cfc646d8ff84aff0c5bf596417e598c /Lib/lib2to3/Grammar.txt | |
| parent | 45217af29c7f380089af17beb48a5ea0560bbb9d (diff) | |
| download | cpython-3c3aa4516c70753de06bb142b6793d01330fcf0f.zip cpython-3c3aa4516c70753de06bb142b6793d01330fcf0f.tar.gz cpython-3c3aa4516c70753de06bb142b6793d01330fcf0f.tar.bz2 | |
lib2to3: Support named assignment expressions (GH-12702)
There are two copies of the grammar -- the one used by Python itself as
Grammar/Grammar, and the one used by lib2to3 which has necessarily diverged at
Lib/lib2to3/Grammar.txt because it needs to support older syntax an we want it
to be reasonable stable to avoid requiring fixer rewrites.
This brings suport for syntax like `if x:= foo():` to match what the live
Python grammar does.
This should've been added at the time of the walrus operator itself, but lib2to3 being
independent is often overlooked. So we do consider this a bugfix rather than enhancement.
Diffstat (limited to 'Lib/lib2to3/Grammar.txt')
| -rw-r--r-- | Lib/lib2to3/Grammar.txt | 10 |
1 files changed, 6 insertions, 4 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 ) |