Index: Misc/NEWS
===================================================================
RCS file: /cvsroot/python/python/dist/src/Misc/NEWS,v
retrieving revision 1.541
diff -c -r1.541 NEWS
*** Misc/NEWS	23 Nov 2002 22:08:15 -0000	1.541
--- Misc/NEWS	26 Nov 2002 09:58:26 -0000
***************
*** 268,273 ****
--- 268,278 ----
    an optional argument that specifies the characters to strip.  For
    example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
  
+ - Dictionaries have a new class method, fromseq(sequence, value=None).
+   It constructs a new dictionary with keys from the sequence and a single
+   constant value.  It is used for building membership tests and for
+   removing duplicates from sequences (or any iterable).
+ 
  - Added a new dict method pop(key).  This removes and returns the
    value corresponding to key.  [SF patch #539949]
  
Index: Objects/dictobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/dictobject.c,v
retrieving revision 2.131
diff -c -r2.131 dictobject.c
*** Objects/dictobject.c	23 Nov 2002 09:45:04 -0000	2.131
--- Objects/dictobject.c	26 Nov 2002 09:58:27 -0000
***************
*** 963,968 ****
--- 963,1014 ----
  }
  
  static PyObject *
+ dict_fromseq(PyObject *mp, PyObject *args)
+ {
+ 	PyObject *seq;
+ 	PyObject *value = Py_None;
+ 	PyObject *it;	/* iter(seq) */
+ 	PyObject *key;
+ 	PyObject *d;
+ 	PyObject *cls;
+ 	int status;
+ 
+ 	if (!PyArg_ParseTuple(args, "OO|O:fromseq", &cls, &seq, &value))
+ 		return NULL;
+ 
+ 	d = PyObject_CallObject(cls, NULL);
+ 	if (d == NULL)
+ 		return NULL;
+ 
+ 	it = PyObject_GetIter(seq);
+ 	if (it == NULL){
+ 		Py_DECREF(d);
+ 		return NULL;
+ 	}
+ 
+ 	for (;;) {
+ 		key = PyIter_Next(it);
+ 		if (key == NULL) {
+ 			if (PyErr_Occurred())
+ 				goto Fail;
+ 			break;
+ 		}
+ 		status = PyDict_SetItem(d, key, value);
+ 		Py_DECREF(key);
+ 		if (status < 0)
+ 			goto Fail;
+ 	}
+ 
+ 	Py_DECREF(it);
+ 	return d;
+ 
+ Fail:
+ 	Py_DECREF(it);
+ 	Py_DECREF(d);
+ 	return NULL;
+ }
+ 
+ static PyObject *
  dict_update(PyObject *mp, PyObject *other)
  {
  	if (PyDict_Update(mp, other) < 0)
***************
*** 1682,1687 ****
--- 1728,1737 ----
  PyDoc_STRVAR(update__doc__,
  "D.update(E) -> None.  Update D from E: for k in E.keys(): D[k] = E[k]");
  
+ PyDoc_STRVAR(fromseq__doc__,
+ "dict.fromseq(S[,v]) -> New dict with keys from S and values equal to v.\n\
+ v defaults to None.");
+ 
  PyDoc_STRVAR(clear__doc__,
  "D.clear() -> None.  Remove all items from D.");
  
***************
*** 1716,1721 ****
--- 1766,1773 ----
  	 values__doc__},
  	{"update",	(PyCFunction)dict_update,	METH_O,
  	 update__doc__},
+ 	{"fromseq",	(PyCFunction)dict_fromseq,	METH_VARARGS | METH_CLASS,
+ 	 fromseq__doc__},
  	{"clear",	(PyCFunction)dict_clear,	METH_NOARGS,
  	 clear__doc__},
  	{"copy",	(PyCFunction)dict_copy,		METH_NOARGS,
Index: Doc/lib/libstdtypes.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/lib/libstdtypes.tex,v
retrieving revision 1.110
diff -c -r1.110 libstdtypes.tex
*** Doc/lib/libstdtypes.tex	16 Nov 2002 00:44:00 -0000	1.110
--- Doc/lib/libstdtypes.tex	26 Nov 2002 09:58:28 -0000
***************
*** 1055,1062 ****
            {(3)}
    \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(3)}
    \lineiii{\var{a}.update(\var{b})}
!           {\code{for k in \var{b}.keys(): \var{a}[k] = \var{b}[k]}}
            {}
    \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(3)}
    \lineiii{\var{a}.get(\var{k}\optional{, \var{x}})}
            {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
--- 1055,1065 ----
            {(3)}
    \lineiii{\var{a}.keys()}{a copy of \var{a}'s list of keys}{(3)}
    \lineiii{\var{a}.update(\var{b})}
!           {\code{for \var{k} in \var{b}.keys(): \var{a}[\var{k}] = \var{b}[\var{k}]}}
            {}
+   \lineiii{\var{a}.fromseq(\var{seq}\optional{, \var{value}})}
+           {Creates a new dictionary with keys from \var{seq} and values from \var{value}}
+           {(7)}			   
    \lineiii{\var{a}.values()}{a copy of \var{a}'s list of values}{(3)}
    \lineiii{\var{a}.get(\var{k}\optional{, \var{x}})}
            {\code{\var{a}[\var{k}]} if \code{\var{k} in \var{a}},
***************
*** 1114,1119 ****
--- 1117,1126 ----
  
  \item[(6)] \function{popitem()} is useful to destructively iterate
  over a dictionary, as often used in set algorithms.
+ \end{description}
+ 
+ \item[(7)] \function{fromseq()} is a class method that returns a
+ new dictionary. \var{value} defaults to \code{None}.  \versionadded{2.3}
  \end{description}
  
  
Index: Lib/test/test_types.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_types.py,v
retrieving revision 1.40
diff -c -r1.40 test_types.py
*** Lib/test/test_types.py	19 Nov 2002 20:49:13 -0000	1.40
--- Lib/test/test_types.py	26 Nov 2002 09:58:28 -0000
***************
*** 530,535 ****
--- 530,559 ----
  try: d.update(FailingUserDict())
  except ValueError: pass
  else: raise TestFailed, 'dict.update(), __getitem__ expected ValueError'
+ # dict.fromseq()
+ if dict.fromseq('abc') != {'a':None, 'b':None, 'c':None}:
+     raise TestFailed, 'dict.fromseq did work as a class method'
+ d = {}
+ if d.fromseq('abc') is d:
+     raise TestFailed, 'dict.fromseq did not return new dict'
+ if d.fromseq('abc') != {'a':None, 'b':None, 'c':None}:
+     raise TestFailed, 'dict.fromseq failed with default value'
+ if d.fromseq((4,5),0) != {4:0, 5:0}:
+     raise TestFailed, 'dict.fromseq failed with specified value'
+ if d.fromseq([]) != {}:
+     raise TestFailed, 'dict.fromseq failed with null sequence'
+ def g():
+     yield 1
+ if d.fromseq(g()) != {1:None}:
+     raise TestFailed, 'dict.fromseq failed with a generator'
+ try: {}.fromseq(3)
+ except TypeError: pass
+ else: raise TestFailed, 'dict.fromseq failed to raise TypeError'
+ class dictlike(dict): pass
+ if dictlike.fromseq('a') != {'a':None}:
+     raise TestFailed, 'dictsubclass.fromseq did not inherit'
+ if type(dictlike.fromseq('a')) is not dictlike:
+     raise TestFailed, 'dictsubclass.fromseq created wrong type'
  # dict.copy()
  d = {1:1, 2:2, 3:3}
  if d.copy() != {1:1, 2:2, 3:3}: raise TestFailed, 'dict copy'