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Iterators phase 1. This comprises:

Browse source 
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???)
This commit is contained in:
Guido van Rossum 2001-04-20 19:13:02 +00:00
parent 12e73bb2f0
commit 59d1d2b434
16 changed files with 256 additions and 25 deletions
Download patch file Download diff file Expand all files Collapse all files

41
Python/ceval.c
View file

@ -381,6 +381,7 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
/* Make it easier to find out where we are with a debugger */
char *filename = PyString_AsString(co->co_filename);
#endif
static PyObject *nextstr;
/* Code access macros */
@ -416,6 +417,11 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
GETLOCAL(i) = value; } while (0)
/* Start of code */
if (nextstr == NULL) {
nextstr = PyString_InternFromString("next");
if (nextstr == NULL)
return NULL;
}
#ifdef USE_STACKCHECK
if (tstate->recursion_depth%10 == 0 && PyOS_CheckStack()) {
@ -1875,6 +1881,41 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
JUMPTO(oparg);
continue;
case GET_ITER:
/* before: [obj]; after [getiter(obj)] */
v = POP();
x = PyObject_GetIter(v);
Py_DECREF(v);
if (x != NULL) {
w = x;
x = PyObject_GetAttr(w, nextstr);
Py_DECREF(w);
if (x != NULL) {
PUSH(x);
continue;
}
}
break;
case FOR_ITER:
/* before: [iter]; after: [iter, iter()] *or* [] */
v = TOP();
x = PyObject_CallObject(v, NULL);
if (x == NULL) {
if (PyErr_ExceptionMatches(
PyExc_StopIteration))
{
PyErr_Clear();
x = v = POP();
Py_DECREF(v);
JUMPBY(oparg);
continue;
}
break;
}
PUSH(x);
continue;
case FOR_LOOP:
/* for v in s: ...
On entry: stack contains s, i.