diff --git a/Lib/sre.py b/Lib/sre.py
index 49e3140bd4f..d5bb462e7bc 100644
--- a/Lib/sre.py
+++ b/Lib/sre.py
@@ -109,16 +109,13 @@ def _subn(pattern, template, string, count=0):
         m = c.search()
         if not m:
             break
-        j = m.start()
-        if j > i:
-            append(string[i:j])
+	b, e = m.span()
+        if i < b:
+            append(string[i:b])
         append(filter(m))
-        i = m.end()
-	if i <= j:
-	    break
+	i = e
         n = n + 1
-    if i < len(string):
-        append(string[i:])
+    append(string[i:])
     return string[:0].join(s), n
 
 def _split(pattern, string, maxsplit=0):
@@ -128,7 +125,7 @@ def _split(pattern, string, maxsplit=0):
     append = s.append
     extend = s.extend
     c = pattern.scanner(string)
-    g = c.groups
+    g = pattern.groups
     while not maxsplit or n < maxsplit:
         m = c.search()
         if not m:
diff --git a/Lib/sre_compile.py b/Lib/sre_compile.py
index 344dc29113f..ea5f5bca3dd 100644
--- a/Lib/sre_compile.py
+++ b/Lib/sre_compile.py
@@ -61,9 +61,9 @@ def _compile(code, pattern, flags):
 	elif op is CATEGORY:
 	    emit(OPCODES[op])
 	    if flags & SRE_FLAG_LOCALE:
-		emit(CH_LOCALE[CHCODES[av]])
+		emit(CHCODES[CH_LOCALE[av]])
 	    elif flags & SRE_FLAG_UNICODE:
-		emit(CH_UNICODE[CHCODES[av]])
+		emit(CHCODES[CH_UNICODE[av]])
 	    else:
 		emit(CHCODES[av])
 	elif op is GROUP:
@@ -92,9 +92,9 @@ def _compile(code, pattern, flags):
 		    emit(fixup(av[1]))
 		elif op is CATEGORY:
 		    if flags & SRE_FLAG_LOCALE:
-			emit(CH_LOCALE[CHCODES[av]])
+			emit(CHCODES[CH_LOCALE[av]])
 		    elif flags & SRE_FLAG_UNICODE:
-			emit(CH_UNICODE[CHCODES[av]])
+			emit(CHCODES[CH_UNICODE[av]])
 		    else:
 			emit(CHCODES[av])
 		else:
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index 93a7b5dc997..ec934fe6b49 100644
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -30,26 +30,27 @@ HEXDIGITS = tuple("0123456789abcdefABCDEF")
 WHITESPACE = string.whitespace
 
 ESCAPES = {
-    "\\a": (LITERAL, chr(7)),
-    "\\b": (LITERAL, chr(8)),
-    "\\f": (LITERAL, chr(12)),
-    "\\n": (LITERAL, chr(10)),
-    "\\r": (LITERAL, chr(13)),
-    "\\t": (LITERAL, chr(9)),
-    "\\v": (LITERAL, chr(11))
+    r"\a": (LITERAL, chr(7)),
+    r"\b": (LITERAL, chr(8)),
+    r"\f": (LITERAL, chr(12)),
+    r"\n": (LITERAL, chr(10)),
+    r"\r": (LITERAL, chr(13)),
+    r"\t": (LITERAL, chr(9)),
+    r"\v": (LITERAL, chr(11)),
+    r"\\": (LITERAL, "\\")
 }
 
 CATEGORIES = {
-    "\\A": (AT, AT_BEGINNING), # start of string
-    "\\b": (AT, AT_BOUNDARY),
-    "\\B": (AT, AT_NON_BOUNDARY),
-    "\\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
-    "\\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
-    "\\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
-    "\\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
-    "\\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
-    "\\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
-    "\\Z": (AT, AT_END), # end of string
+    r"\A": (AT, AT_BEGINNING), # start of string
+    r"\b": (AT, AT_BOUNDARY),
+    r"\B": (AT, AT_NON_BOUNDARY),
+    r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
+    r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
+    r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
+    r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
+    r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
+    r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
+    r"\Z": (AT, AT_END), # end of string
 }
 
 FLAGS = {
@@ -185,11 +186,11 @@ def isname(name):
 	    return 0
     return 1
 
-def _group(escape, state):
+def _group(escape, groups):
     # check if the escape string represents a valid group
     try:
 	group = int(escape[1:])
-	if group and group < state.groups:
+	if group and group < groups:
 	    return group
     except ValueError:
 	pass
@@ -239,10 +240,10 @@ def _escape(source, escape, state):
 	    return LITERAL, chr(int(escape[-4:], 16) & 0xff)
 	elif escape[1:2] in DIGITS:
 	    while 1:
-		group = _group(escape, state)
+		group = _group(escape, state.groups)
 		if group:
 		    if (not source.next or
-			not _group(escape + source.next, state)):
+			not _group(escape + source.next, state.groups)):
 		        return GROUP, group
 		    escape = escape + source.get()
 		elif source.next in OCTDIGITS:
@@ -534,6 +535,7 @@ def parse_template(source, pattern):
 	if this is None:
 	    break # end of replacement string
 	if this and this[0] == "\\":
+	    # group
 	    if this == "\\g":
 		name = ""
 		if s.match("<"):
@@ -557,15 +559,29 @@ def parse_template(source, pattern):
 			raise IndexError, "unknown group name"
 		a((MARK, index))
 	    elif len(this) > 1 and this[1] in DIGITS:
-		while s.next in DIGITS:
-		    this = this + s.get()
-		a((MARK, int(this[1:])))
+		code = None
+		while 1:
+		    group = _group(this, pattern.groups+1)
+		    if group:
+			if (not s.next or
+			    not _group(this + s.next, pattern.groups+1)):
+		            code = MARK, int(group)
+			    break
+		    elif s.next in OCTDIGITS:
+			this = this + s.get()
+		    else:
+			break
+		if not code:
+		    this = this[1:]
+		    # FIXME: support unicode characters!
+		    code = LITERAL, chr(int(this[-6:], 8) & 0xff)
+		a(code)
 	    else:
 		try:
 		    a(ESCAPES[this])
 		except KeyError:
-		    for char in this:
-			a((LITERAL, char))
+		    for c in this:
+			a((LITERAL, c))
 	else:
 	    a((LITERAL, this))
     return p
diff --git a/Modules/_sre.c b/Modules/_sre.c
index 6b0fa61a708..7b1adbd177f 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -1534,6 +1534,9 @@ pattern_getattr(PatternObject* self, char* name)
     if (!strcmp(name, "flags"))
 		return Py_BuildValue("i", self->flags);
 
+    if (!strcmp(name, "groups"))
+		return Py_BuildValue("i", self->groups);
+
 	if (!strcmp(name, "groupindex") && self->groupindex) {
         Py_INCREF(self->groupindex);
 		return self->groupindex;
@@ -1939,9 +1942,6 @@ scanner_getattr(ScannerObject* self, char* name)
 		return self->pattern;
     }
 
-    if (!strcmp(name, "groups"))
-		return Py_BuildValue("i", ((PatternObject*) self->pattern)->groups);
-
 	PyErr_SetString(PyExc_AttributeError, name);
 	return NULL;
 }