bltinmodule.c

/* Built-in functions */

#include "Python.h"

#include "node.h"
#include "code.h"
#include "eval.h"

#include <ctype.h>

#ifdef RISCOS
#include "unixstuff.h"
#endif

/* The default encoding used by the platform file system APIs
   Can remain NULL for all platforms that don't have such a concept
*/
#if defined(MS_WINDOWS) && defined(HAVE_USABLE_WCHAR_T)
const char *Py_FileSystemDefaultEncoding = "mbcs";
#elif defined(__APPLE__)
const char *Py_FileSystemDefaultEncoding = "utf-8";
#else
const char *Py_FileSystemDefaultEncoding = NULL; /* use default */
#endif

/* Forward */
static PyObject *filterstring(PyObject *, PyObject *);
#ifdef Py_USING_UNICODE
static PyObject *filterunicode(PyObject *, PyObject *);
#endif
static PyObject *filtertuple (PyObject *, PyObject *);

static PyObject *
builtin___import__(PyObject *self, PyObject *args, PyObject *kwds)
{
	static char *kwlist[] = {"name", "globals", "locals", "fromlist",
				 "level", 0};
	char *name;
	PyObject *globals = NULL;
	PyObject *locals = NULL;
	PyObject *fromlist = NULL;
	int level = -1;

	if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|OOOi:__import__",
			kwlist, &name, &globals, &locals, &fromlist, &level))
		return NULL;
	return PyImport_ImportModuleLevel(name, globals, locals,
					  fromlist, level);
}

PyDoc_STRVAR(import_doc,
"__import__(name, globals={}, locals={}, fromlist=[], level=-1) -> module\n\
\n\
Import a module.  The globals are only used to determine the context;\n\
they are not modified.  The locals are currently unused.  The fromlist\n\
should be a list of names to emulate ``from name import ...'', or an\n\
empty list to emulate ``import name''.\n\
When importing a module from a package, note that __import__('A.B', ...)\n\
returns package A when fromlist is empty, but its submodule B when\n\
fromlist is not empty.  Level is used to determine whether to perform \n\
absolute or relative imports.  -1 is the original strategy of attempting\n\
both absolute and relative imports, 0 is absolute, a positive number\n\
is the number of parent directories to search relative to the current module.");


static PyObject *
builtin_abs(PyObject *self, PyObject *v)
{
	return PyNumber_Absolute(v);
}

PyDoc_STRVAR(abs_doc,
"abs(number) -> number\n\
\n\
Return the absolute value of the argument.");

static PyObject *
builtin_all(PyObject *self, PyObject *v)
{
	PyObject *it, *item;

	it = PyObject_GetIter(v);
	if (it == NULL)
		return NULL;

	while ((item = PyIter_Next(it)) != NULL) {
		int cmp = PyObject_IsTrue(item);
		Py_DECREF(item);
		if (cmp < 0) {
			Py_DECREF(it);
			return NULL;
		}
		if (cmp == 0) {
			Py_DECREF(it);
			Py_RETURN_FALSE;
		}
	}
	Py_DECREF(it);
	if (PyErr_Occurred())
		return NULL;
	Py_RETURN_TRUE;
}

PyDoc_STRVAR(all_doc,
"all(iterable) -> bool\n\
\n\
Return True if bool(x) is True for all values x in the iterable.");

static PyObject *
builtin_any(PyObject *self, PyObject *v)
{
	PyObject *it, *item;

	it = PyObject_GetIter(v);
	if (it == NULL)
		return NULL;

	while ((item = PyIter_Next(it)) != NULL) {
		int cmp = PyObject_IsTrue(item);
		Py_DECREF(item);
		if (cmp < 0) {
			Py_DECREF(it);
			return NULL;
		}
		if (cmp == 1) {
			Py_DECREF(it);
			Py_RETURN_TRUE;
		}
	}
	Py_DECREF(it);
	if (PyErr_Occurred())
		return NULL;
	Py_RETURN_FALSE;
}

PyDoc_STRVAR(any_doc,
"any(iterable) -> bool\n\
\n\
Return True if bool(x) is True for any x in the iterable.");

static PyObject *
builtin_apply(PyObject *self, PyObject *args)
{
	PyObject *func, *alist = NULL, *kwdict = NULL;
	PyObject *t = NULL, *retval = NULL;

	if (!PyArg_UnpackTuple(args, "apply", 1, 3, &func, &alist, &kwdict))
		return NULL;
	if (alist != NULL) {
		if (!PyTuple_Check(alist)) {
			if (!PySequence_Check(alist)) {
				PyErr_Format(PyExc_TypeError,
				     "apply() arg 2 expected sequence, found %s",
					     alist->ob_type->tp_name);
				return NULL;
			}
			t = PySequence_Tuple(alist);
			if (t == NULL)
				return NULL;
			alist = t;
		}
	}
	if (kwdict != NULL && !PyDict_Check(kwdict)) {
		PyErr_Format(PyExc_TypeError,
			     "apply() arg 3 expected dictionary, found %s",
			     kwdict->ob_type->tp_name);
		goto finally;
	}
	retval = PyEval_CallObjectWithKeywords(func, alist, kwdict);
  finally:
	Py_XDECREF(t);
	return retval;
}

PyDoc_STRVAR(apply_doc,
"apply(object[, args[, kwargs]]) -> value\n\
\n\
Call a callable object with positional arguments taken from the tuple args,\n\
and keyword arguments taken from the optional dictionary kwargs.\n\
Note that classes are callable, as are instances with a __call__() method.\n\
\n\
Deprecated since release 2.3. Instead, use the extended call syntax:\n\
    function(*args, **keywords).");


static PyObject *
builtin_callable(PyObject *self, PyObject *v)
{
	return PyBool_FromLong((long)PyCallable_Check(v));
}

PyDoc_STRVAR(callable_doc,
"callable(object) -> bool\n\
\n\
Return whether the object is callable (i.e., some kind of function).\n\
Note that classes are callable, as are instances with a __call__() method.");


static PyObject *
builtin_filter(PyObject *self, PyObject *args)
{
	PyObject *func, *seq, *result, *it, *arg;
	Py_ssize_t len;   /* guess for result list size */
	register Py_ssize_t j;

	if (!PyArg_UnpackTuple(args, "filter", 2, 2, &func, &seq))
		return NULL;

	/* Strings and tuples return a result of the same type. */
	if (PyString_Check(seq))
		return filterstring(func, seq);
#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(seq))
		return filterunicode(func, seq);
#endif
	if (PyTuple_Check(seq))
		return filtertuple(func, seq);

	/* Pre-allocate argument list tuple. */
	arg = PyTuple_New(1);
	if (arg == NULL)
		return NULL;

	/* Get iterator. */
	it = PyObject_GetIter(seq);
	if (it == NULL)
		goto Fail_arg;

	/* Guess a result list size. */
	len = _PyObject_LengthHint(seq);
	if (len < 0) {
		if (!PyErr_ExceptionMatches(PyExc_TypeError)  &&
		    !PyErr_ExceptionMatches(PyExc_AttributeError)) {
			goto Fail_it;
		}
		PyErr_Clear();
		len = 8;	/* arbitrary */
	}

	/* Get a result list. */
	if (PyList_Check(seq) && seq->ob_refcnt == 1) {
		/* Eww - can modify the list in-place. */
		Py_INCREF(seq);
		result = seq;
	}
	else {
		result = PyList_New(len);
		if (result == NULL)
			goto Fail_it;
	}

	/* Build the result list. */
	j = 0;
	for (;;) {
		PyObject *item;
		int ok;

		item = PyIter_Next(it);
		if (item == NULL) {
			if (PyErr_Occurred())
				goto Fail_result_it;
			break;
		}

		if (func == (PyObject *)&PyBool_Type || func == Py_None) {
			ok = PyObject_IsTrue(item);
		}
		else {
			PyObject *good;
			PyTuple_SET_ITEM(arg, 0, item);
			good = PyObject_Call(func, arg, NULL);
			PyTuple_SET_ITEM(arg, 0, NULL);
			if (good == NULL) {
				Py_DECREF(item);
				goto Fail_result_it;
			}
			ok = PyObject_IsTrue(good);
			Py_DECREF(good);
		}
		if (ok) {
			if (j < len)
				PyList_SET_ITEM(result, j, item);
			else {
				int status = PyList_Append(result, item);
				Py_DECREF(item);
				if (status < 0)
					goto Fail_result_it;
			}
			++j;
		}
		else
			Py_DECREF(item);
	}


	/* Cut back result list if len is too big. */
	if (j < len && PyList_SetSlice(result, j, len, NULL) < 0)
		goto Fail_result_it;

	Py_DECREF(it);
	Py_DECREF(arg);
	return result;

Fail_result_it:
	Py_DECREF(result);
Fail_it:
	Py_DECREF(it);
Fail_arg:
	Py_DECREF(arg);
	return NULL;
}

PyDoc_STRVAR(filter_doc,
"filter(function or None, sequence) -> list, tuple, or string\n"
"\n"
"Return those items of sequence for which function(item) is true.  If\n"
"function is None, return the items that are true.  If sequence is a tuple\n"
"or string, return the same type, else return a list.");

static PyObject *
builtin_chr(PyObject *self, PyObject *args)
{
	long x;
	char s[1];

	if (!PyArg_ParseTuple(args, "l:chr", &x))
		return NULL;
	if (x < 0 || x >= 256) {
		PyErr_SetString(PyExc_ValueError,
				"chr() arg not in range(256)");
		return NULL;
	}
	s[0] = (char)x;
	return PyString_FromStringAndSize(s, 1);
}

PyDoc_STRVAR(chr_doc,
"chr(i) -> character\n\
\n\
Return a string of one character with ordinal i; 0 <= i < 256.");


#ifdef Py_USING_UNICODE
static PyObject *
builtin_unichr(PyObject *self, PyObject *args)
{
	long x;

	if (!PyArg_ParseTuple(args, "l:unichr", &x))
		return NULL;

	return PyUnicode_FromOrdinal(x);
}

PyDoc_STRVAR(unichr_doc,
"unichr(i) -> Unicode character\n\
\n\
Return a Unicode string of one character with ordinal i; 0 <= i <= 0x10ffff.");
#endif


static PyObject *
builtin_cmp(PyObject *self, PyObject *args)
{
	PyObject *a, *b;
	int c;

	if (!PyArg_UnpackTuple(args, "cmp", 2, 2, &a, &b))
		return NULL;
	if (PyObject_Cmp(a, b, &c) < 0)
		return NULL;
	return PyInt_FromLong((long)c);
}

PyDoc_STRVAR(cmp_doc,
"cmp(x, y) -> integer\n\
\n\
Return negative if x<y, zero if x==y, positive if x>y.");


static PyObject *
builtin_coerce(PyObject *self, PyObject *args)
{
	PyObject *v, *w;
	PyObject *res;

	if (!PyArg_UnpackTuple(args, "coerce", 2, 2, &v, &w))
		return NULL;
	if (PyNumber_Coerce(&v, &w) < 0)
		return NULL;
	res = PyTuple_Pack(2, v, w);
	Py_DECREF(v);
	Py_DECREF(w);
	return res;
}

PyDoc_STRVAR(coerce_doc,
"coerce(x, y) -> (x1, y1)\n\
\n\
Return a tuple consisting of the two numeric arguments converted to\n\
a common type, using the same rules as used by arithmetic operations.\n\
If coercion is not possible, raise TypeError.");

static PyObject *
builtin_compile(PyObject *self, PyObject *args)
{
	char *str;
	char *filename;
	char *startstr;
	int start;
	int dont_inherit = 0;
	int supplied_flags = 0;
	PyCompilerFlags cf;
	PyObject *result = NULL, *cmd, *tmp = NULL;
	Py_ssize_t length;

	if (!PyArg_ParseTuple(args, "Oss|ii:compile", &cmd, &filename,
			      &startstr, &supplied_flags, &dont_inherit))
		return NULL;

	cf.cf_flags = supplied_flags;

#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(cmd)) {
		tmp = PyUnicode_AsUTF8String(cmd);
		if (tmp == NULL)
			return NULL;
		cmd = tmp;
		cf.cf_flags |= PyCF_SOURCE_IS_UTF8;
	}
#endif
	if (PyObject_AsReadBuffer(cmd, (const void **)&str, &length))
		return NULL;
	if ((size_t)length != strlen(str)) {
		PyErr_SetString(PyExc_TypeError,
				"compile() expected string without null bytes");
		goto cleanup;
	}

	if (strcmp(startstr, "exec") == 0)
		start = Py_file_input;
	else if (strcmp(startstr, "eval") == 0)
		start = Py_eval_input;
	else if (strcmp(startstr, "single") == 0)
		start = Py_single_input;
	else {
		PyErr_SetString(PyExc_ValueError,
		   "compile() arg 3 must be 'exec' or 'eval' or 'single'");
		goto cleanup;
	}

	if (supplied_flags &
	    ~(PyCF_MASK | PyCF_MASK_OBSOLETE | PyCF_DONT_IMPLY_DEDENT | PyCF_ONLY_AST))
	{
		PyErr_SetString(PyExc_ValueError,
				"compile(): unrecognised flags");
		goto cleanup;
	}
	/* XXX Warn if (supplied_flags & PyCF_MASK_OBSOLETE) != 0? */

	if (!dont_inherit) {
		PyEval_MergeCompilerFlags(&cf);
	}
	result = Py_CompileStringFlags(str, filename, start, &cf);
cleanup:
	Py_XDECREF(tmp);
	return result;
}

PyDoc_STRVAR(compile_doc,
"compile(source, filename, mode[, flags[, dont_inherit]]) -> code object\n\
\n\
Compile the source string (a Python module, statement or expression)\n\
into a code object that can be executed by the exec statement or eval().\n\
The filename will be used for run-time error messages.\n\
The mode must be 'exec' to compile a module, 'single' to compile a\n\
single (interactive) statement, or 'eval' to compile an expression.\n\
The flags argument, if present, controls which future statements influence\n\
the compilation of the code.\n\
The dont_inherit argument, if non-zero, stops the compilation inheriting\n\
the effects of any future statements in effect in the code calling\n\
compile; if absent or zero these statements do influence the compilation,\n\
in addition to any features explicitly specified.");

static PyObject *
builtin_dir(PyObject *self, PyObject *args)
{
	PyObject *arg = NULL;

	if (!PyArg_UnpackTuple(args, "dir", 0, 1, &arg))
		return NULL;
	return PyObject_Dir(arg);
}

PyDoc_STRVAR(dir_doc,
"dir([object]) -> list of strings\n"
"\n"
"Return an alphabetized list of names comprising (some of) the attributes\n"
"of the given object, and of attributes reachable from it:\n"
"\n"
"No argument:  the names in the current scope.\n"
"Module object:  the module attributes.\n"
"Type or class object:  its attributes, and recursively the attributes of\n"
"    its bases.\n"
"Otherwise:  its attributes, its class's attributes, and recursively the\n"
"    attributes of its class's base classes.");

static PyObject *
builtin_divmod(PyObject *self, PyObject *args)
{
	PyObject *v, *w;

	if (!PyArg_UnpackTuple(args, "divmod", 2, 2, &v, &w))
		return NULL;
	return PyNumber_Divmod(v, w);
}

PyDoc_STRVAR(divmod_doc,
"divmod(x, y) -> (div, mod)\n\
\n\
Return the tuple ((x-x%y)/y, x%y).  Invariant: div*y + mod == x.");


static PyObject *
builtin_eval(PyObject *self, PyObject *args)
{
	PyObject *cmd, *result, *tmp = NULL;
	PyObject *globals = Py_None, *locals = Py_None;
	char *str;
	PyCompilerFlags cf;

	if (!PyArg_UnpackTuple(args, "eval", 1, 3, &cmd, &globals, &locals))
		return NULL;
	if (locals != Py_None && !PyMapping_Check(locals)) {
		PyErr_SetString(PyExc_TypeError, "locals must be a mapping");
		return NULL;
	}
	if (globals != Py_None && !PyDict_Check(globals)) {
		PyErr_SetString(PyExc_TypeError, PyMapping_Check(globals) ?
			"globals must be a real dict; try eval(expr, {}, mapping)"
			: "globals must be a dict");
		return NULL;
	}
	if (globals == Py_None) {
		globals = PyEval_GetGlobals();
		if (locals == Py_None)
			locals = PyEval_GetLocals();
	}
	else if (locals == Py_None)
		locals = globals;

	if (globals == NULL || locals == NULL) {
		PyErr_SetString(PyExc_TypeError, 
			"eval must be given globals and locals "
			"when called without a frame");
		return NULL;
	}

	if (PyDict_GetItemString(globals, "__builtins__") == NULL) {
		if (PyDict_SetItemString(globals, "__builtins__",
					 PyEval_GetBuiltins()) != 0)
			return NULL;
	}

	if (PyCode_Check(cmd)) {
		if (PyCode_GetNumFree((PyCodeObject *)cmd) > 0) {
			PyErr_SetString(PyExc_TypeError,
		"code object passed to eval() may not contain free variables");
			return NULL;
		}
		return PyEval_EvalCode((PyCodeObject *) cmd, globals, locals);
	}

	if (!PyString_Check(cmd) &&
	    !PyUnicode_Check(cmd)) {
		PyErr_SetString(PyExc_TypeError,
			   "eval() arg 1 must be a string or code object");
		return NULL;
	}
	cf.cf_flags = 0;

#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(cmd)) {
		tmp = PyUnicode_AsUTF8String(cmd);
		if (tmp == NULL)
			return NULL;
		cmd = tmp;
		cf.cf_flags |= PyCF_SOURCE_IS_UTF8;
	}
#endif
	if (PyString_AsStringAndSize(cmd, &str, NULL)) {
		Py_XDECREF(tmp);
		return NULL;
	}
	while (*str == ' ' || *str == '\t')
		str++;

	(void)PyEval_MergeCompilerFlags(&cf);
	result = PyRun_StringFlags(str, Py_eval_input, globals, locals, &cf);
	Py_XDECREF(tmp);
	return result;
}

PyDoc_STRVAR(eval_doc,
"eval(source[, globals[, locals]]) -> value\n\
\n\
Evaluate the source in the context of globals and locals.\n\
The source may be a string representing a Python expression\n\
or a code object as returned by compile().\n\
The globals must be a dictionary and locals can be any mapping,\n\
defaulting to the current globals and locals.\n\
If only globals is given, locals defaults to it.\n");


static PyObject *
builtin_execfile(PyObject *self, PyObject *args)
{
	char *filename;
	PyObject *globals = Py_None, *locals = Py_None;
	PyObject *res;
	FILE* fp = NULL;
	PyCompilerFlags cf;
	int exists;

	if (!PyArg_ParseTuple(args, "s|O!O:execfile",
			&filename,
			&PyDict_Type, &globals,
			&locals))
		return NULL;
	if (locals != Py_None && !PyMapping_Check(locals)) {
		PyErr_SetString(PyExc_TypeError, "locals must be a mapping");
		return NULL;
	}
	if (globals == Py_None) {
		globals = PyEval_GetGlobals();
		if (locals == Py_None)
			locals = PyEval_GetLocals();
	}
	else if (locals == Py_None)
		locals = globals;
	if (PyDict_GetItemString(globals, "__builtins__") == NULL) {
		if (PyDict_SetItemString(globals, "__builtins__",
					 PyEval_GetBuiltins()) != 0)
			return NULL;
	}

	exists = 0;
	/* Test for existence or directory. */
#if defined(PLAN9)
	{
		Dir *d;

		if ((d = dirstat(filename))!=nil) {
			if(d->mode & DMDIR)
				werrstr("is a directory");
			else
				exists = 1;
			free(d);
		}
	}
#elif defined(RISCOS)
	if (object_exists(filename)) {
		if (isdir(filename))
			errno = EISDIR;
		else
			exists = 1;
	}
#else	/* standard Posix */
	{
		struct stat s;
		if (stat(filename, &s) == 0) {
			if (S_ISDIR(s.st_mode))
#				if defined(PYOS_OS2) && defined(PYCC_VACPP)
					errno = EOS2ERR;
#				else
					errno = EISDIR;
#				endif
			else
				exists = 1;
		}
	}
#endif

        if (exists) {
		Py_BEGIN_ALLOW_THREADS
		fp = fopen(filename, "r" PY_STDIOTEXTMODE);
		Py_END_ALLOW_THREADS

		if (fp == NULL) {
			exists = 0;
		}
        }

	if (!exists) {
		PyErr_SetFromErrnoWithFilename(PyExc_IOError, filename);
		return NULL;
	}
	cf.cf_flags = 0;
	if (PyEval_MergeCompilerFlags(&cf))
		res = PyRun_FileExFlags(fp, filename, Py_file_input, globals,
				   locals, 1, &cf);
	else
		res = PyRun_FileEx(fp, filename, Py_file_input, globals,
				   locals, 1);
	return res;
}

PyDoc_STRVAR(execfile_doc,
"execfile(filename[, globals[, locals]])\n\
\n\
Read and execute a Python script from a file.\n\
The globals and locals are dictionaries, defaulting to the current\n\
globals and locals.  If only globals is given, locals defaults to it.");


static PyObject *
builtin_getattr(PyObject *self, PyObject *args)
{
	PyObject *v, *result, *dflt = NULL;
	PyObject *name;

	if (!PyArg_UnpackTuple(args, "getattr", 2, 3, &v, &name, &dflt))
		return NULL;
#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(name)) {
		name = _PyUnicode_AsDefaultEncodedString(name, NULL);
		if (name == NULL)
			return NULL;
	}
#endif

	if (!PyString_Check(name)) {
		PyErr_SetString(PyExc_TypeError,
				"getattr(): attribute name must be string");
		return NULL;
	}
	result = PyObject_GetAttr(v, name);
	if (result == NULL && dflt != NULL &&
	    PyErr_ExceptionMatches(PyExc_AttributeError))
	{
		PyErr_Clear();
		Py_INCREF(dflt);
		result = dflt;
	}
	return result;
}

PyDoc_STRVAR(getattr_doc,
"getattr(object, name[, default]) -> value\n\
\n\
Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.\n\
When a default argument is given, it is returned when the attribute doesn't\n\
exist; without it, an exception is raised in that case.");


static PyObject *
builtin_globals(PyObject *self)
{
	PyObject *d;

	d = PyEval_GetGlobals();
	Py_XINCREF(d);
	return d;
}

PyDoc_STRVAR(globals_doc,
"globals() -> dictionary\n\
\n\
Return the dictionary containing the current scope's global variables.");


static PyObject *
builtin_hasattr(PyObject *self, PyObject *args)
{
	PyObject *v;
	PyObject *name;

	if (!PyArg_UnpackTuple(args, "hasattr", 2, 2, &v, &name))
		return NULL;
#ifdef Py_USING_UNICODE
	if (PyUnicode_Check(name)) {
		name = _PyUnicode_AsDefaultEncodedString(name, NULL);
		if (name == NULL)
			return NULL;
	}
#endif

	if (!PyString_Check(name)) {
		PyErr_SetString(PyExc_TypeError,
				"hasattr(): attribute name must be string");
		return NULL;
	}
	v = PyObject_GetAttr(v, name);
	if (v == NULL) {
		PyErr_Clear();
		Py_INCREF(Py_False);
		return Py_False;
	}
	Py_DECREF(v);
	Py_INCREF(Py_True);
	return Py_True;
}

PyDoc_STRVAR(hasattr_doc,
"hasattr(object, name) -> bool\n\
\n\
Return whether the object has an attribute with the given name.\n\
(This is done by calling getattr(object, name) and catching exceptions.)");


static PyObject *
builtin_id(PyObject *self, PyObject *v)
{
	return PyLong_FromVoidPtr(v);
}

PyDoc_STRVAR(id_doc,
"id(object) -> integer\n\
\n\
Return the identity of an object.  This is guaranteed to be unique among\n\
simultaneously existing objects.  (Hint: it's the object's memory address.)");


static PyObject *
builtin_map(PyObject *self, PyObject *args)
{
	typedef struct {
		PyObject *it;	/* the iterator object */
		int saw_StopIteration;  /* bool:  did the iterator end? */
	} sequence;

	PyObject *func, *result;
	sequence *seqs = NULL, *sqp;
	Py_ssize_t n, len;
	register int i, j;

	n = PyTuple_Size(args);
	if (n < 2) {
		PyErr_SetString(PyExc_TypeError,
				"map() requires at least two args");
		return NULL;
	}

	func = PyTuple_GetItem(args, 0);
	n--;

	if (func == Py_None && n == 1) {
		/* map(None, S) is the same as list(S). */
		return PySequence_List(PyTuple_GetItem(args, 1));
	}

	/* Get space for sequence descriptors.  Must NULL out the iterator
	 * pointers so that jumping to Fail_2 later doesn't see trash.
	 */
	if ((seqs = PyMem_NEW(sequence, n)) == NULL) {
		PyErr_NoMemory();
		return NULL;
	}
	for (i = 0; i < n; ++i) {
		seqs[i].it = (PyObject*)NULL;
		seqs[i].saw_StopIteration = 0;
	}

	/* Do a first pass to obtain iterators for the arguments, and set len
	 * to the largest of their lengths.
	 */
	len = 0;
	for (i = 0, sqp = seqs; i < n; ++i, ++sqp) {
		PyObject *curseq;
		Py_ssize_t curlen;

		/* Get iterator. */
		curseq = PyTuple_GetItem(args, i+1);
		sqp->it = PyObject_GetIter(curseq);
		if (sqp->it == NULL) {
			static char errmsg[] =
			    "argument %d to map() must support iteration";
			char errbuf[sizeof(errmsg) + 25];
			PyOS_snprintf(errbuf, sizeof(errbuf), errmsg, i+2);
			PyErr_SetString(PyExc_TypeError, errbuf);
			goto Fail_2;
		}

		/* Update len. */
		curlen = _PyObject_LengthHint(curseq);
		if (curlen < 0) {
			if (!PyErr_ExceptionMatches(PyExc_TypeError)  &&
			    !PyErr_ExceptionMatches(PyExc_AttributeError)) {
				goto Fail_2;
			}
			PyErr_Clear();
			curlen = 8;  /* arbitrary */
		}
		if (curlen > len)
			len = curlen;
	}

	/* Get space for the result list. */
	if ((result = (PyObject *) PyList_New(len)) == NULL)
		goto Fail_2;

	/* Iterate over the sequences until all have stopped. */
	for (i = 0; ; ++i) {
		PyObject *alist, *item=NULL, *value;
		int numactive = 0;

		if (func == Py_None && n == 1)
			alist = NULL;
		else if ((alist = PyTuple_New(n)) == NULL)
			goto Fail_1;

		for (j = 0, sqp = seqs; j < n; ++j, ++sqp) {
			if (sqp->saw_StopIteration) {
				Py_INCREF(Py_None);
				item = Py_None;
			}
			else {
				item = PyIter_Next(sqp->it);
				if (item)
					++numactive;
				else {
					if (PyErr_Occurred()) {
						Py_XDECREF(alist);
						goto Fail_1;
					}
					Py_INCREF(Py_None);
					item = Py_None;
					sqp->saw_StopIteration = 1;
				}
			}
			if (alist)
				PyTuple_SET_ITEM(alist, j, item);
			else
				break;
		}

		if (!alist)
			alist = item;

		if (numactive == 0) {
			Py_DECREF(alist);
			break;
		}

		if (func == Py_None)
			value = alist;
		else {
			value = PyEval_CallObject(func, alist);
			Py_DECREF(alist);
			if (value == NULL)
				goto Fail_1;
		}
		if (i >= len) {
			int status = PyList_Append(result, value);
			Py_DECREF(value);
			if (status < 0)
				goto Fail_1;
		}
		else if (PyList_SetItem(result, i, value) < 0)
		 	goto Fail_1;
	}

	if (i < len && PyList_SetSlice(result, i, len, NULL) < 0)
		goto Fail_1;

	goto Succeed;

Fail_1:
	Py_DECREF(result);
Fail_2:
	result = NULL;
Succeed:
	assert(seqs);
	for (i = 0; i < n; ++i)
		Py_XDECREF(seqs[i].it);
	PyMem_DEL(seqs);
	return result;
}

PyDoc_STRVAR(map_doc,
"map(function, sequence[, sequence, ...]) -> list\n\
\n\
Return a list of the results of applying the function to the items of\n\
the argument sequence(s).  If more than one sequence is given, the\n\
function is called with an argument list consisting of the corresponding\n\
item of each sequence, substituting None for missing values when not all\n\
sequences have the same length.  If the function is None, return a list of\n\
the items of the sequence (or a list of tuples if more than one sequence).");


static PyObject *
builtin_setattr(PyObject *self, PyObject *args)
{
	PyObject *v;
	PyObject *name;
	PyObject *value;

	if (!PyArg_UnpackTuple(args, "setattr", 3, 3, &v, &name, &value))
		return NULL;
	if (PyObject_SetAttr(v, name, value) != 0)