diff --git a/Lib/inspect.py b/Lib/inspect.py
index eeb54d2..2d88bc1 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -349,28 +349,32 @@
             return self.lines[i]
         else: return ''
 
+class EndOfBlock(Exception): pass
+
+class BlockFinder:
+    """Provide a tokeneater() method to detect the end of a code block."""
+    def __init__(self):
+        self.indent = 0
+        self.started = 0
+        self.last = 0
+
+    def tokeneater(self, type, token, (srow, scol), (erow, ecol), line):
+        if not self.started:
+            if type == tokenize.NAME: self.started = 1
+        elif type == tokenize.NEWLINE:
+            self.last = srow
+        elif type == tokenize.INDENT:
+            self.indent = self.indent + 1
+        elif type == tokenize.DEDENT:
+            self.indent = self.indent - 1
+            if self.indent == 0: raise EndOfBlock, self.last
+
 def getblock(lines):
     """Extract the block of code at the top of the given list of lines."""
-
-    indent = 0
-    started = 0
-    last = 0
-    tokens = tokenize.generate_tokens(ListReader(lines).readline)
-
-    for (type, token, (srow, scol), (erow, ecol), line) in tokens:
-        if not started:
-            if type == tokenize.NAME:
-                started = 1
-        elif type == tokenize.NEWLINE:
-            last = srow
-        elif type == tokenize.INDENT:
-            indent = indent + 1
-        elif type == tokenize.DEDENT:
-            indent = indent - 1
-            if indent == 0:
-                return lines[:last]
-    else:
-        raise ValueError, "unable to find block"
+    try:
+        tokenize.tokenize(ListReader(lines).readline, BlockFinder().tokeneater)
+    except EndOfBlock, eob:
+        return lines[:eob.args[0]]
 
 def getsourcelines(object):
     """Return a list of source lines and starting line number for an object.
diff --git a/Lib/tabnanny.py b/Lib/tabnanny.py
index 8323a33..35e5cfa 100755
--- a/Lib/tabnanny.py
+++ b/Lib/tabnanny.py
@@ -14,6 +14,8 @@
 import sys
 import getopt
 import tokenize
+if not hasattr(tokenize, 'NL'):
+    raise ValueError("tokenize.NL doesn't exist -- tokenize module too old")
 
 __all__ = ["check"]
 
@@ -243,15 +245,11 @@
         prefix = prefix + "s"
     return prefix + " " + string.join(firsts, ', ')
 
-# Need Guido's enhancement
-assert hasattr(tokenize, 'NL'), "tokenize module too old"
-
-def process_tokens(tokens,
-                   INDENT=tokenize.INDENT,
-                   DEDENT=tokenize.DEDENT,
-                   NEWLINE=tokenize.NEWLINE,
-                   JUNK=(tokenize.COMMENT, tokenize.NL)):
-
+def process_tokens(tokens):
+    INDENT = tokenize.INDENT
+    DEDENT = tokenize.DEDENT
+    NEWLINE = tokenize.NEWLINE
+    JUNK = tokenize.COMMENT, tokenize.NL
     indents = [Whitespace("")]
     check_equal = 0
 
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index b3ee4a8..b79cdc0 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -1,13 +1,26 @@
 """Tokenization help for Python programs.
 
-This module exports a function called 'tokenize()' that breaks a stream of
+generate_tokens(readline) is a generator that breaks a stream of
 text into Python tokens.  It accepts a readline-like method which is called
-repeatedly to get the next line of input (or "" for EOF) and a "token-eater"
-function which is called once for each token found.  The latter function is
-passed the token type, a string containing the token, the starting and
-ending (row, column) coordinates of the token, and the original line.  It is
-designed to match the working of the Python tokenizer exactly, except that
-it produces COMMENT tokens for comments and gives type OP for all operators."""
+repeatedly to get the next line of input (or "" for EOF).  It generates
+5-tuples with these members:
+
+    the token type (see token.py)
+    the token (a string)
+    the starting (row, column) indices of the token (a 2-tuple of ints)
+    the ending (row, column) indices of the token (a 2-tuple of ints)
+    the original line (string)
+
+It is designed to match the working of the Python tokenizer exactly, except
+that it produces COMMENT tokens for comments and gives type OP for all
+operators
+
+Older entry points
+    tokenize_loop(readline, tokeneater)
+    tokenize(readline, tokeneater=printtoken)
+are the same, except instead of generating tokens, tokeneater is a callback
+function to which the 5 fields described above are passed as 5 arguments,
+each time a new token is found."""
 
 __author__ = 'Ka-Ping Yee <ping@lfw.org>'
 __credits__ = \
@@ -111,7 +124,7 @@
     except StopTokenizing:
         pass
 
-# backwards compatible interface, probably not used
+# backwards compatible interface
 def tokenize_loop(readline, tokeneater):
     for token_info in generate_tokens(readline):
         apply(tokeneater, token_info)