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loewisloewis
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Patch #957398: Add public API for Generator Object/Type.
1 parent 09e2cb0 commit e440e47

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Lines changed: 207 additions & 138 deletions

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‎Doc/api/concrete.tex‎

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@@ -2603,3 +2603,34 @@ \subsection{Cell Objects \label{cell-objects}}
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reference counts are adjusted, and no checks are made for safety;
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\var{cell} must be non-\NULL{} and must be a cell object.
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\end{cfuncdesc}
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\subsection{Generator Objects \label{gen-objects}}
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Generator objects are what Python uses to implement generator iterators.
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They are normally created by iterating over a function that yields values,
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rather than explicitly calling \cfunction{PyGen_New}.
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\begin{ctypedesc}{PyGenObject}
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The C structure used for generator objects.
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\end{ctypedesc}
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\begin{cvardesc}{PyTypeObject}{PyGen_Type}
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The type object corresponding to generator objects
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\end{cvardesc}
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\begin{cfuncdesc}{int}{PyGen_Check}{ob}
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Return true if \var{ob} is a generator object; \var{ob} must not be
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\NULL.
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\end{cfuncdesc}
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\begin{cfuncdesc}{int}{PyGen_CheckExact}{ob}
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Return true if \var{ob}'s type is \var{PyGen_Type}
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is a generator object; \var{ob} must not be
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\NULL.
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\end{cfuncdesc}
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\begin{cfuncdesc}{PyObject*}{PyGen_New}{PyFrameObject *frame}
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Create and return a new generator object based on the \var{frame} object.
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The parameter must not be \NULL.
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\end{cfuncdesc}

‎Include/ceval.h‎

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@@ -64,6 +64,7 @@ PyAPI_FUNC(char *) PyEval_GetFuncName(PyObject *);
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PyAPI_FUNC(char *) PyEval_GetFuncDesc(PyObject *);
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PyAPI_FUNC(PyObject *) PyEval_GetCallStats(PyObject *);
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PyAPI_FUNC(PyObject *) PyEval_EvaluateFrame(PyObject *);
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/* this used to be handled on a per-thread basis - now just two globals */
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PyAPI_DATA(volatile int) _Py_Ticker;

‎Include/genobject.h‎

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/* Generator object interface */
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#ifndef Py_GENOBJECT_H
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#define Py_GENOBJECT_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct {
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PyObject_HEAD
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/* The gi_ prefix is intended to remind of generator-iterator. */
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PyFrameObject *gi_frame;
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/* True if generator is being executed. */
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int gi_running;
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/* List of weak reference. */
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PyObject *gi_weakreflist;
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} PyGenObject;
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PyAPI_DATA(PyTypeObject) PyGen_Type;
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#define PyGen_Check(op) PyObject_TypeCheck(op, &PyGen_Type)
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#define PyGen_CheckExact(op) ((op)->ob_type == &PyGen_Type)
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PyAPI_FUNC(PyObject *) PyGen_New(PyFrameObject *);
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_GENOBJECT_H */

‎Makefile.pre.in‎

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@@ -261,6 +261,7 @@ OBJECT_OBJS= \
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Objects/complexobject.o \
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Objects/descrobject.o \
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Objects/enumobject.o \
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Objects/genobject.o \
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Objects/fileobject.o \
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Objects/floatobject.o \
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Objects/frameobject.o \
@@ -478,6 +479,7 @@ PYTHON_HEADERS= \
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Include/descrobject.h \
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Include/dictobject.h \
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Include/enumobject.h \
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Include/genobject.h \
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Include/fileobject.h \
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Include/floatobject.h \
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Include/funcobject.h \

‎Misc/NEWS‎

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@@ -497,6 +497,9 @@ Build
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C API
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-----
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- New public functions PyEval_EvaluateFrame and PyGen_New to expose
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generator objects.
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- New public functions Py_IncRef() and Py_DecRef(), exposing the
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functionality of the Py_XINCREF() and Py_XDECREF macros. Useful for
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runtime dynamic embedding of Python. See patch #938302, by Bob

‎Objects/genobject.c‎

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/* Generator object implementation */
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#include "Python.h"
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#include "frameobject.h"
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#include "genobject.h"
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#include "ceval.h"
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#include "structmember.h"
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static int
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gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
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{
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return visit((PyObject *)gen->gi_frame, arg);
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}
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static void
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gen_dealloc(PyGenObject *gen)
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{
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_PyObject_GC_UNTRACK(gen);
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if (gen->gi_weakreflist != NULL)
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PyObject_ClearWeakRefs((PyObject *) gen);
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Py_DECREF(gen->gi_frame);
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PyObject_GC_Del(gen);
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}
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static PyObject *
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gen_iternext(PyGenObject *gen)
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{
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PyThreadState *tstate = PyThreadState_GET();
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PyFrameObject *f = gen->gi_frame;
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PyObject *result;
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if (gen->gi_running) {
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PyErr_SetString(PyExc_ValueError,
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"generator already executing");
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return NULL;
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}
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if (f->f_stacktop == NULL)
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return NULL;
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/* Generators always return to their most recent caller, not
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* necessarily their creator. */
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Py_XINCREF(tstate->frame);
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assert(f->f_back == NULL);
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f->f_back = tstate->frame;
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gen->gi_running = 1;
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result = PyEval_EvaluateFrame((PyObject *)f);
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gen->gi_running = 0;
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/* Don't keep the reference to f_back any longer than necessary. It
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* may keep a chain of frames alive or it could create a reference
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* cycle. */
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Py_XDECREF(f->f_back);
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f->f_back = NULL;
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/* If the generator just returned (as opposed to yielding), signal
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* that the generator is exhausted. */
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if (result == Py_None && f->f_stacktop == NULL) {
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Py_DECREF(result);
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result = NULL;
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}
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return result;
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}
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static PyObject *
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gen_getiter(PyObject *gen)
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{
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Py_INCREF(gen);
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return gen;
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}
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static PyMemberDef gen_memberlist[] = {
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{"gi_frame", T_OBJECT, offsetof(PyGenObject, gi_frame), RO},
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{"gi_running", T_INT, offsetof(PyGenObject, gi_running), RO},
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{NULL} /* Sentinel */
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};
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PyTypeObject PyGen_Type = {
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PyObject_HEAD_INIT(&PyType_Type)
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0, /* ob_size */
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"generator", /* tp_name */
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sizeof(PyGenObject), /* tp_basicsize */
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0, /* tp_itemsize */
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/* methods */
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(destructor)gen_dealloc, /* tp_dealloc */
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0, /* tp_print */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_compare */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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PyObject_GenericGetAttr, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
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0, /* tp_doc */
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(traverseproc)gen_traverse, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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offsetof(PyGenObject, gi_weakreflist), /* tp_weaklistoffset */
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(getiterfunc)gen_getiter, /* tp_iter */
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(iternextfunc)gen_iternext, /* tp_iternext */
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0, /* tp_methods */
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gen_memberlist, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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};
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PyObject *
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PyGen_New(PyFrameObject *f)
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{
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PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
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if (gen == NULL) {
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Py_DECREF(f);
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return NULL;
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}
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gen->gi_frame = f;
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gen->gi_running = 0;
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gen->gi_weakreflist = NULL;
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_PyObject_GC_TRACK(gen);
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return (PyObject *)gen;
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}

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