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???)

--- a/Include/opcode.h	Fri Apr 20 19:04:55 2001 +0000
+++ b/Include/opcode.h	Fri Apr 20 19:13:02 2001 +0000
@@ -53,6 +53,7 @@
 #define BINARY_XOR	65
 #define BINARY_OR	66
 #define INPLACE_POWER	67
+#define GET_ITER	68
 
 #define PRINT_EXPR	70
 #define PRINT_ITEM	71
@@ -80,6 +81,7 @@
 #define STORE_NAME	90	/* Index in name list */
 #define DELETE_NAME	91	/* "" */
 #define UNPACK_SEQUENCE	92	/* Number of sequence items */
+#define FOR_ITER	93
 
 #define STORE_ATTR	95	/* Index in name list */
 #define DELETE_ATTR	96	/* "" */