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| author | Guido van Rossum <guido@python.org> | 2001-10-15 15:44:05 (GMT) |
|---|---|---|
| committer | Guido van Rossum <guido@python.org> | 2001-10-15 15:44:05 (GMT) |
| commit | 1c917072ca2895a196de7f397d4e96bcc577e13d (patch) | |
| tree | 866e2babdb9b21e5869012c583a191898ac68a92 /Grammar | |
| parent | 69c0ff38362dff3b0a90828b8d787dfb3eb14bc3 (diff) | |
| download | cpython-1c917072ca2895a196de7f397d4e96bcc577e13d.zip cpython-1c917072ca2895a196de7f397d4e96bcc577e13d.tar.gz cpython-1c917072ca2895a196de7f397d4e96bcc577e13d.tar.bz2 | |
Very subtle syntax change: in a list comprehension, the testlist in
"for <var> in <testlist> may no longer be a single test followed by
a comma. This solves SF bug #431886. Note that if the testlist
contains more than one test, a trailing comma is still allowed, for
maximum backward compatibility; but this example is not:
[(x, y) for x in range(10), for y in range(10)]
^
The fix involved creating a new nonterminal 'testlist_safe' whose
definition doesn't allow the trailing comma if there's only one test:
testlist_safe: test [(',' test)+ [',']]
Diffstat (limited to 'Grammar')
| -rw-r--r-- | Grammar/Grammar | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Grammar/Grammar b/Grammar/Grammar index d85863e..6ac0cbc 100644 --- a/Grammar/Grammar +++ b/Grammar/Grammar @@ -89,6 +89,7 @@ subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop] sliceop: ':' [test] exprlist: expr (',' expr)* [','] testlist: test (',' test)* [','] +testlist_safe: test [(',' test)+ [',']] dictmaker: test ':' test (',' test ':' test)* [','] classdef: 'class' NAME ['(' testlist ')'] ':' suite @@ -97,5 +98,5 @@ arglist: (argument ',')* (argument [',']| '*' test [',' '**' test] | '**' test) argument: [test '='] test # Really [keyword '='] test list_iter: list_for | list_if -list_for: 'for' exprlist 'in' testlist [list_iter] +list_for: 'for' exprlist 'in' testlist_safe [list_iter] list_if: 'if' test [list_iter] |