diff -r a729dfdbd24b Doc/library/exceptions.rst
--- a/Doc/library/exceptions.rst	Thu Mar 24 22:32:56 2011 +0200
+++ b/Doc/library/exceptions.rst	Fri Mar 25 01:43:13 2011 +0100
@@ -289,6 +289,12 @@
    This is a subclass of :exc:`IndentationError`.
 
 
+.. exception:: ParserError
+
+   Raised when the parser encounters an error due to internal limitations.
+   This is a subclass of :exc:`SyntaxError`.
+
+
 .. exception:: SystemError
 
    Raised when the interpreter finds an internal error, but the situation does not
diff -r a729dfdbd24b Include/errcode.h
--- a/Include/errcode.h	Thu Mar 24 22:32:56 2011 +0200
+++ b/Include/errcode.h	Fri Mar 25 01:43:13 2011 +0100
@@ -30,6 +30,7 @@
 #define E_EOLS		24	/* EOL in single-quoted string */
 #define E_LINECONT	25	/* Unexpected characters after a line continuation */
 #define E_IDENTIFIER    26      /* Invalid characters in identifier */
+#define E_TOONESTED     27      /* Too many opening parens */
 
 #ifdef __cplusplus
 }
diff -r a729dfdbd24b Include/pyerrors.h
--- a/Include/pyerrors.h	Thu Mar 24 22:32:56 2011 +0200
+++ b/Include/pyerrors.h	Fri Mar 25 01:43:13 2011 +0100
@@ -149,6 +149,7 @@
 PyAPI_DATA(PyObject *) PyExc_SyntaxError;
 PyAPI_DATA(PyObject *) PyExc_IndentationError;
 PyAPI_DATA(PyObject *) PyExc_TabError;
+PyAPI_DATA(PyObject *) PyExc_ParserError;
 PyAPI_DATA(PyObject *) PyExc_ReferenceError;
 PyAPI_DATA(PyObject *) PyExc_SystemError;
 PyAPI_DATA(PyObject *) PyExc_SystemExit;
diff -r a729dfdbd24b Lib/test/exception_hierarchy.txt
--- a/Lib/test/exception_hierarchy.txt	Thu Mar 24 22:32:56 2011 +0200
+++ b/Lib/test/exception_hierarchy.txt	Fri Mar 25 01:43:13 2011 +0100
@@ -29,7 +29,8 @@
       |    +-- NotImplementedError
       +-- SyntaxError
       |    +-- IndentationError
-      |         +-- TabError
+      |    |    +-- TabError
+      |    +-- ParserError
       +-- SystemError
       +-- TypeError
       +-- ValueError
diff -r a729dfdbd24b Lib/test/test_parser.py
--- a/Lib/test/test_parser.py	Thu Mar 24 22:32:56 2011 +0200
+++ b/Lib/test/test_parser.py	Fri Mar 25 01:43:13 2011 +0100
@@ -542,10 +542,7 @@
 
     def test_trigger_memory_error(self):
         e = self._nested_expression(100)
-        print("Expecting 's_push: parser stack overflow' in next line",
-              file=sys.stderr)
-        sys.stderr.flush()
-        self.assertRaises(MemoryError, parser.expr, e)
+        self.assertRaises(ParserError, parser.expr, e)
 
 class STObjectTestCase(unittest.TestCase):
     """Test operations on ST objects themselves"""
diff -r a729dfdbd24b Objects/exceptions.c
--- a/Objects/exceptions.c	Thu Mar 24 22:32:56 2011 +0200
+++ b/Objects/exceptions.c	Fri Mar 25 01:43:13 2011 +0100
@@ -1063,6 +1063,14 @@
 
 
 /*
+ *    ParserError extends SyntaxError
+ */
+MiddlingExtendsException(PyExc_SyntaxError, ParserError, SyntaxError,
+                         "Raised when the parser encounters an error due "
+                         "to internal limitations.");
+
+
+/*
  *    LookupError extends Exception
  */
 SimpleExtendsException(PyExc_Exception, LookupError,
@@ -1998,6 +2006,7 @@
     PRE_INIT(SyntaxError)
     PRE_INIT(IndentationError)
     PRE_INIT(TabError)
+    PRE_INIT(ParserError)
     PRE_INIT(LookupError)
     PRE_INIT(IndexError)
     PRE_INIT(KeyError)
@@ -2061,6 +2070,7 @@
     POST_INIT(SyntaxError)
     POST_INIT(IndentationError)
     POST_INIT(TabError)
+    POST_INIT(ParserError)
     POST_INIT(LookupError)
     POST_INIT(IndexError)
     POST_INIT(KeyError)
diff -r a729dfdbd24b Parser/parser.c
--- a/Parser/parser.c	Thu Mar 24 22:32:56 2011 +0200
+++ b/Parser/parser.c	Fri Mar 25 01:43:13 2011 +0100
@@ -39,8 +39,7 @@
 {
     register stackentry *top;
     if (s->s_top == s->s_base) {
-        fprintf(stderr, "s_push: parser stack overflow\n");
-        return E_NOMEM;
+        return E_TOONESTED;
     }
     top = --s->s_top;
     top->s_dfa = d;
diff -r a729dfdbd24b Python/pythonrun.c
--- a/Python/pythonrun.c	Thu Mar 24 22:32:56 2011 +0200
+++ b/Python/pythonrun.c	Fri Mar 25 01:43:13 2011 +0100
@@ -2052,6 +2052,10 @@
     case E_IDENTIFIER:
         msg = "invalid character in identifier";
         break;
+    case E_TOONESTED:
+        errtype = PyExc_ParserError;
+        msg = "too many opening parens";
+        break;
     default:
         fprintf(stderr, "error=%d\n", err->error);
         msg = "unknown parsing error";