Make identifiers str (not str8) objects throughout. This affects the parser, various object implementations, and all places that put identifiers into C string literals. In testing, a number of crashes occurred as code would fail when the recursion limit was reached (such as the Unicode interning dictionary having key/value pairs where key is not value). To solve these, I added an overflowed flag, which allows for 50 more recursions after the limit was reached and the exception was raised, and a recursion_critical flag, which indicates that recursion absolutely must be allowed, i.e. that a certain call must not cause a stack overflow exception. There are still some places where both str and str8 are accepted as identifiers; these should eventually be removed.

--- a/Objects/complexobject.c	Sat Jun 09 16:13:23 2007 +0000
+++ b/Objects/complexobject.c	Sun Jun 10 09:51:05 2007 +0000
@@ -269,7 +269,7 @@
         {
 		PyObject *complexfunc;
 		if (!complex_str) {
-			if (!(complex_str = PyString_FromString("__complex__")))
+			if (!(complex_str = PyUnicode_FromString("__complex__")))
 				return cv;
 		}
 		complexfunc = _PyType_Lookup(op->ob_type, complex_str);
@@ -900,7 +900,7 @@
 
 	/* XXX Hack to support classes with __complex__ method */
 	if (complexstr == NULL) {
-		complexstr = PyString_InternFromString("__complex__");
+		complexstr = PyUnicode_InternFromString("__complex__");
 		if (complexstr == NULL)
 			return NULL;
 	}