diff options
Diffstat (limited to 'Doc/reference/expressions.rst')
| -rw-r--r-- | Doc/reference/expressions.rst | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index 8837344e5dd..24544a055c3 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -134,8 +134,7 @@ Literals Python supports string and bytes literals and various numeric literals: .. productionlist:: python-grammar - literal: `stringliteral` | `bytesliteral` - : | `integer` | `floatnumber` | `imagnumber` + literal: `stringliteral` | `bytesliteral` | `NUMBER` Evaluation of a literal yields an object of the given type (string, bytes, integer, floating-point number, complex number) with the given value. The value @@ -406,8 +405,9 @@ brackets or curly braces. Variables used in the generator expression are evaluated lazily when the :meth:`~generator.__next__` method is called for the generator object (in the same fashion as normal generators). However, the iterable expression in the -leftmost :keyword:`!for` clause is immediately evaluated, so that an error -produced by it will be emitted at the point where the generator expression +leftmost :keyword:`!for` clause is immediately evaluated, and the +:term:`iterator` is immediately created for that iterable, so that an error +produced while creating the iterator will be emitted at the point where the generator expression is defined, rather than at the point where the first value is retrieved. Subsequent :keyword:`!for` clauses and any filter condition in the leftmost :keyword:`!for` clause cannot be evaluated in the enclosing scope as they may @@ -625,8 +625,10 @@ is already executing raises a :exc:`ValueError` exception. .. method:: generator.close() - Raises a :exc:`GeneratorExit` at the point where the generator function was - paused. If the generator function catches the exception and returns a + Raises a :exc:`GeneratorExit` exception at the point where the generator + function was paused (equivalent to calling ``throw(GeneratorExit)``). + The exception is raised by the yield expression where the generator was paused. + If the generator function catches the exception and returns a value, this value is returned from :meth:`close`. If the generator function is already closed, or raises :exc:`GeneratorExit` (by not catching the exception), :meth:`close` returns :const:`None`. If the generator yields a @@ -1023,7 +1025,7 @@ series of :term:`arguments <argument>`: : ["," `keywords_arguments`] : | `starred_and_keywords` ["," `keywords_arguments`] : | `keywords_arguments` - positional_arguments: positional_item ("," positional_item)* + positional_arguments: `positional_item` ("," `positional_item`)* positional_item: `assignment_expression` | "*" `expression` starred_and_keywords: ("*" `expression` | `keyword_item`) : ("," "*" `expression` | "," `keyword_item`)* @@ -1928,7 +1930,7 @@ Expression lists single: , (comma); expression list .. productionlist:: python-grammar - starred_expression: ["*"] `or_expr` + starred_expression: "*" `or_expr` | `expression` flexible_expression: `assignment_expression` | `starred_expression` flexible_expression_list: `flexible_expression` ("," `flexible_expression`)* [","] starred_expression_list: `starred_expression` ("," `starred_expression`)* [","] |