Implementation of PEP-0217.
This closes the PEP, and patch 103170
diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index 2fda26e..df32182 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -44,6 +44,15 @@
Availability: Windows.
\end{datadesc}
+\begin{funcdesc}{displayhook}{\var{value}}
+If \var{value} is not \code{None}, this function prints it to
+\code{sys.stdout}, and saves it in \code{__builtin__._}.
+
+This function is called when an expression is entered at the prompt
+of an interactive Python session. It exists mainly so it can be
+overridden.
+\end{funcdesc}
+
\begin{funcdesc}{exc_info}{}
This function returns a tuple of three values that give information
about the exception that is currently being handled. The information
diff --git a/Python/ceval.c b/Python/ceval.c
index 5110746..8012b83 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1245,36 +1245,26 @@
case PRINT_EXPR:
v = POP();
- /* Print value except if None */
- /* After printing, also assign to '_' */
- /* Before, set '_' to None to avoid recursion */
- if (v != Py_None &&
- (err = PyDict_SetItemString(
- f->f_builtins, "_", Py_None)) == 0) {
- err = Py_FlushLine();
- if (err == 0) {
- x = PySys_GetObject("stdout");
- if (x == NULL) {
- PyErr_SetString(
- PyExc_RuntimeError,
- "lost sys.stdout");
- err = -1;
- }
- }
- if (err == 0)
- err = PyFile_WriteObject(v, x, 0);
- if (err == 0) {
- PyFile_SoftSpace(x, 1);
- err = Py_FlushLine();
- }
- if (err == 0) {
- err = PyDict_SetItemString(
- f->f_builtins, "_", v);
- }
+ w = PySys_GetObject("displayhook");
+ if (w == NULL) {
+ PyErr_SetString(PyExc_RuntimeError,
+ "lost sys.displayhook");
+ err = -1;
+ }
+ if (err == 0) {
+ x = Py_BuildValue("(O)", v);
+ if (x == NULL)
+ err = -1;
+ }
+ if (err == 0) {
+ w = PyEval_CallObject(w, x);
+ if (w == NULL)
+ err = -1;
}
Py_DECREF(v);
+ Py_XDECREF(x);
break;
-
+
case PRINT_ITEM_TO:
w = stream = POP();
/* fall through to PRINT_ITEM */
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 33d71ac..037b567 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -68,6 +68,50 @@
}
static PyObject *
+sys_displayhook(PyObject *self, PyObject *args)
+{
+ PyObject *o, *stdout;
+ PyInterpreterState *interp = PyThreadState_Get()->interp;
+ PyObject *modules = interp->modules;
+ PyObject *builtins = PyDict_GetItemString(modules, "__builtin__");
+
+ /* parse arguments */
+ if (!PyArg_ParseTuple(args, "O:displayhook", &o))
+ return NULL;
+
+ /* Print value except if None */
+ /* After printing, also assign to '_' */
+ /* Before, set '_' to None to avoid recursion */
+ if (o == Py_None) {
+ Py_INCREF(Py_None);
+ return Py_None;
+ }
+ if (PyObject_SetAttrString(builtins, "_", Py_None) != 0)
+ return NULL;
+ if (Py_FlushLine() != 0)
+ return NULL;
+ stdout = PySys_GetObject("stdout");
+ if (stdout == NULL) {
+ PyErr_SetString(PyExc_RuntimeError, "lost sys.stdout");
+ return NULL;
+ }
+ if (PyFile_WriteObject(o, stdout, 0) != 0)
+ return NULL;
+ PyFile_SoftSpace(stdout, 1);
+ if (Py_FlushLine() != 0)
+ return NULL;
+ if (PyObject_SetAttrString(builtins, "_", o) != 0)
+ return NULL;
+ Py_INCREF(Py_None);
+ return Py_None;
+}
+
+static char displayhook_doc[] =
+"displayhook(o) -> None\n"
+"\n"
+"Print o to the stdout, and save it in __builtin__._\n";
+
+static PyObject *
sys_exc_info(PyObject *self, PyObject *args)
{
PyThreadState *tstate;
@@ -332,6 +376,7 @@
static PyMethodDef sys_methods[] = {
/* Might as well keep this in alphabetic order */
+ {"displayhook", sys_displayhook, 1, displayhook_doc},
{"exc_info", sys_exc_info, 1, exc_info_doc},
{"exit", sys_exit, 0, exit_doc},
{"getdefaultencoding", sys_getdefaultencoding, 1,
@@ -475,6 +520,7 @@
\n\
Functions:\n\
\n\
+displayhook() -- print an object to the screen, and save it in __builtin__._\n\
exc_info() -- return thread-safe information about the current exception\n\
exit() -- exit the interpreter by raising SystemExit\n\
getrefcount() -- return the reference count for an object (plus one :-)\n\