The third and final doc-string sweep by Ka-Ping Yee.

The attached patches update the standard library so that all modules
have docstrings beginning with one-line summaries.

A new docstring was added to formatter.  The docstring for os.py
was updated to mention nt, os2, ce in addition to posix, dos, mac.

Lib/traceback.py

@@ -1,4 +1,4 @@
-# Format and print Python stack traces
+"""Extract, format and print information about Python stack traces."""
 
 import linecache
 import string
@@ -10,6 +10,8 @@ def _print(file, str='', terminator='\n'):
 
 
 def print_list(extracted_list, file=None):
+	"""Print the list of tuples as returned by extract_tb() or
+	extract_stack() as a formatted stack trace to the given file."""
 	if not file:
 		file = sys.stderr
 	for filename, lineno, name, line in extracted_list:
@@ -19,6 +21,12 @@ def print_list(extracted_list, file=None):
 			_print(file, '    %s' % string.strip(line))
 
 def format_list(extracted_list):
+	"""Given a list of tuples as returned by extract_tb() or
+	extract_stack(), return a list of strings ready for printing.
+	Each string in the resulting list corresponds to the item with
+	the same index in the argument list.  Each string ends in a
+	newline; the strings may contain internal newlines as well, for
+	those items whose source text line is not None."""
 	list = []
 	for filename, lineno, name, line in extracted_list:
 		item = '  File "%s", line %d, in %s\n' % (filename,lineno,name)
@@ -29,6 +37,10 @@ def format_list(extracted_list):
 	
 
 def print_tb(tb, limit=None, file=None):
+	"""Print up to 'limit' stack trace entries from the traceback 'tb'.
+	If 'limit' is omitted or None, all entries are printed.  If 'file' is
+	omitted or None, the output goes to sys.stderr; otherwise 'file'
+	should be an open file or file-like object with a write() method."""
 	if not file:
 		file = sys.stderr
 	if limit is None:
@@ -49,9 +61,18 @@ def print_tb(tb, limit=None, file=None):
 		n = n+1
 
 def format_tb(tb, limit = None):
+	"""A shorthand for 'format_list(extract_stack(f, limit))."""
 	return format_list(extract_tb(tb, limit))
 
 def extract_tb(tb, limit = None):
+	"""Return a list of up to 'limit' pre-processed stack trace entries
+	extracted from the traceback object 'traceback'.  This is useful for
+	alternate formatting of stack traces.  If 'limit' is omitted or None,
+	all entries are extracted.  A pre-processed stack trace entry is a
+	quadruple (filename, line number, function name, text) representing
+	the information that is usually printed for a stack trace.  The text
+	is a string with leading and trailing whitespace stripped; if the
+	source is not available it is None."""
 	if limit is None:
 		if hasattr(sys, 'tracebacklimit'):
 			limit = sys.tracebacklimit
@@ -73,6 +94,14 @@ def extract_tb(tb, limit = None):
 
 
 def print_exception(etype, value, tb, limit=None, file=None):
+	"""Print exception information and up to 'limit' stack trace entries
+	from the traceback 'tb' to 'file'.  This differs from print_tb() in
+	the following ways: (1) if traceback is not None, it prints a header
+	"Traceback (innermost last):"; (2) it prints the exception type and
+	value after the stack trace; (3) if type is SyntaxError and value has
+	the appropriate format, it prints the line where the syntax error
+	occurred with a caret on the next line indicating the approximate
+	position of the error."""
 	if not file:
 		file = sys.stderr
 	if tb:
@@ -84,6 +113,12 @@ def print_exception(etype, value, tb, limit=None, file=None):
 	_print(file, lines[-1], '')
 
 def format_exception(etype, value, tb, limit = None):
+	"""Format a stack trace and the exception information.  The arguments
+	have the same meaning as the corresponding arguments to
+	print_exception().  The return value is a list of strings, each
+	ending in a newline and some containing internal newlines.  When 
+	these lines are contatenated and printed, exactly the same text is
+	printed as does print_exception()."""
 	if tb:
 		list = ['Traceback (innermost last):\n']
 		list = list + format_tb(tb, limit)
@@ -93,6 +128,14 @@ def format_exception(etype, value, tb, limit = None):
 	return list
 
 def format_exception_only(etype, value):
+	"""Format the exception part of a traceback.  The arguments are the
+	exception type and value such as given by sys.last_type and
+	sys.last_value. The return value is a list of strings, each ending
+	in a newline.  Normally, the list contains a single string;
+	however, for SyntaxError exceptions, it contains several lines that
+	(when printed) display detailed information about where the syntax
+	error occurred.  The message indicating which exception occurred is
+	the always last string in the list."""
 	list = []
 	if type(etype) == types.ClassType:
 		stype = etype.__name__
@@ -128,6 +171,10 @@ def format_exception_only(etype, value):
 
 
 def print_exc(limit=None, file=None):
+	"""This is a shorthand for 'print_exception(sys.exc_type,
+	sys.exc_value, sys.exc_traceback, limit, file)'.
+	(In fact, it uses sys.exc_info() to retrieve the same information
+	in a thread-safe way.)"""
 	if not file:
 		file = sys.stderr
 	try:
@@ -137,6 +184,8 @@ def print_exc(limit=None, file=None):
 	    etype = value = tb = None
 
 def print_last(limit=None, file=None):
+	"""This is a shorthand for 'print_exception(sys.last_type,
+	sys.last_value, sys.last_traceback, limit, file)'."""
 	if not file:
 		file = sys.stderr
 	print_exception(sys.last_type, sys.last_value, sys.last_traceback,
@@ -144,6 +193,10 @@ def print_last(limit=None, file=None):
 
 
 def print_stack(f=None, limit=None, file=None):
+	"""This function prints a stack trace from its invocation point.
+	The optional 'f' argument can be used to specify an alternate stack
+	frame at which to start. The optional 'limit' and 'file' arguments
+	have the same meaning as for print_exception()."""
 	if f is None:
 		try:
 			raise ZeroDivisionError
@@ -152,6 +205,7 @@ def print_stack(f=None, limit=None, file=None):
 	print_list(extract_stack(f, limit), file)
 
 def format_stack(f=None, limit=None):
+	"""A shorthand for 'format_list(extract_stack(f, limit))'."""
 	if f is None:
 		try:
 			raise ZeroDivisionError
@@ -160,6 +214,12 @@ def format_stack(f=None, limit=None):
 	return format_list(extract_stack(f, limit))
 
 def extract_stack(f=None, limit = None):
+	"""Extract the raw traceback from the current stack frame.  The
+	return value has the same format as for extract_tb().  The optional
+	'f' and 'limit' arguments have the same meaning as for print_stack(). 
+	Each item in the list is a quadruple (filename, line number,
+	function name, text), and the entries are in order from outermost
+	to innermost stack frame."""
 	if f is None:
 		try:
 			raise ZeroDivisionError
@@ -184,13 +244,14 @@ def extract_stack(f=None, limit = None):
 	list.reverse()
 	return list
 
-# Calculate the correct line number of the traceback given in tb (even
-# with -O on).
-# Coded by Marc-Andre Lemburg from the example of PyCode_Addr2Line()
-# in compile.c.
-# Revised version by Jim Hugunin to work with JPython too.
-
 def tb_lineno(tb):
+	"""Calculate the correct line number of the traceback given in tb
+	(even with -O on)."""
+
+	# Coded by Marc-Andre Lemburg from the example of PyCode_Addr2Line()
+	# in compile.c.
+	# Revised version by Jim Hugunin to work with JPython too.
+
 	c = tb.tb_frame.f_code
 	if not hasattr(c, 'co_lnotab'):
 		return tb.tb_lineno