diff --git a/Doc/howto/functional.rst b/Doc/howto/functional.rst index c7f8bc8f17f..695b9b31a76 100644 --- a/Doc/howto/functional.rst +++ b/Doc/howto/functional.rst @@ -589,7 +589,7 @@ generator function. In addition to :meth:`~generator.send`, there are two other methods on generators: -* :meth:`throw(type, value=None, traceback=None) ` is used to +* :meth:`throw(value) ` is used to raise an exception inside the generator; the exception is raised by the ``yield`` expression where the generator's execution is paused. diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst index 804332ffab6..8ac9a8c0566 100644 --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -2984,7 +2984,8 @@ generators, coroutines do not directly support iteration. :exc:`StopIteration`, or other exception) is the same as when iterating over the :meth:`__await__` return value, described above. -.. method:: coroutine.throw(type[, value[, traceback]]) +.. method:: coroutine.throw(value) + coroutine.throw(type[, value[, traceback]]) Raises the specified exception in the coroutine. This method delegates to the :meth:`~generator.throw` method of the iterator that caused diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index bb6d1dc1cdd..b914c48d3d4 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -561,14 +561,27 @@ is already executing raises a :exc:`ValueError` exception. could receive the value. -.. method:: generator.throw(type[, value[, traceback]]) +.. method:: generator.throw(value) + generator.throw(type[, value[, traceback]]) - Raises an exception of type ``type`` at the point where the generator was paused, + Raises an exception at the point where the generator was paused, and returns the next value yielded by the generator function. If the generator exits without yielding another value, a :exc:`StopIteration` exception is raised. If the generator function does not catch the passed-in exception, or raises a different exception, then that exception propagates to the caller. + In typical use, this is called with a single exception instance similar to the + way the :keyword:`raise` keyword is used. + + For backwards compatability, however, the second signature is + supported, following a convention from older versions of Python. + The *type* argument should be an exception class, and *value* + should be an exception instance. If the *value* is not provided, the + *type* constructor is called to get an instance. If *traceback* + is provided, it is set on the exception, otherwise any existing + :attr:`~BaseException.__traceback__` attribute stored in *value* may + be cleared. + .. index:: exception: GeneratorExit diff --git a/Objects/genobject.c b/Objects/genobject.c index f071390d6d3..cdb2a0f76b0 100644 --- a/Objects/genobject.c +++ b/Objects/genobject.c @@ -410,8 +410,11 @@ gen_close(PyGenObject *gen, PyObject *args) PyDoc_STRVAR(throw_doc, -"throw(typ[,val[,tb]]) -> raise exception in generator,\n\ -return next yielded value or raise StopIteration."); +"throw(value)\n\ +throw(type[,value[,tb]])\n\ +\n\ +Raise exception in generator, return next yielded value or raise\n\ +StopIteration."); static PyObject * _gen_throw(PyGenObject *gen, int close_on_genexit, @@ -1157,8 +1160,11 @@ PyDoc_STRVAR(coro_send_doc, return next iterated value or raise StopIteration."); PyDoc_STRVAR(coro_throw_doc, -"throw(typ[,val[,tb]]) -> raise exception in coroutine,\n\ -return next iterated value or raise StopIteration."); +"throw(value)\n\ +throw(type[,value[,traceback]])\n\ +\n\ +Raise exception in coroutine, return next iterated value or raise\n\ +StopIteration."); PyDoc_STRVAR(coro_close_doc, "close() -> raise GeneratorExit inside coroutine.");