Iterators phase 1. This comprises:

new slot tp_iter in type object, plus new flag Py_TPFLAGS_HAVE_ITER
new C API PyObject_GetIter(), calls tp_iter
new builtin iter(), with two forms: iter(obj), and iter(function, sentinel)
new internal object types iterobject and calliterobject
new exception StopIteration
new opcodes for "for" loops, GET_ITER and FOR_ITER (also supported by dis.py)
new magic number for .pyc files
new special method for instances: __iter__() returns an iterator
iteration over dictionaries: "for x in dict" iterates over the keys
iteration over files: "for x in file" iterates over lines

TODO:

documentation
test suite
decide whether to use a different way to spell iter(function, sentinal)
decide whether "for key in dict" is a good idea
use iterators in map/filter/reduce, min/max, and elsewhere (in/not in?)
speed tuning (make next() a slot tp_next???)

1 files changed, 17 insertions, 0 deletions

diff --git a/Objects/abstract.c b/Objects/abstract.c
index 3ccac71..8a6df76 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -1738,3 +1738,20 @@ PyObject_IsSubclass(PyObject *derived, PyObject *cls)
 
 	return retval;
 }
+
+PyObject *
+PyObject_GetIter(PyObject *o)
+{
+	PyTypeObject *t = o->ob_type;
+	getiterfunc f = NULL;
+	if (PyType_HasFeature(t, Py_TPFLAGS_HAVE_ITER))
+		f = t->tp_iter;
+	if (f == NULL) {
+		if (PySequence_Check(o))
+			return PyIter_New(o);
+		PyErr_SetString(PyExc_TypeError, "iter() of non-sequence");
+		return NULL;
+	}
+	else
+		return (*f)(o);
+}