added __doc__ strings etc.

Lib/anydbm.py

@@ -1,9 +1,50 @@
-"""A generic interface to all dbm clones."""
+"""A generic interface to all dbm clones.
+
+Instead of
+
+	import dbm
+	d = dbm.open(file, 'rw', 0666)
+
+use
+
+	import anydbm
+	d = anydbm.open(file)
+
+The returned object is a dbm, gdbm or (on the Mac) dbmac object,
+dependent on availability of the modules (tested in this order).
+
+It has the following interface (key and data are strings):
+
+	d[key] = data	# store data at key (may override data at
+			# existing key)
+	data = d[key]	# retrieve data at key (raise KeyError if no
+			# such key)
+	del d[key]	# delete data stored at key (raises KeyError
+			# if no such key)
+	flag = d.has_key(key)	# true if the key exists
+	list = d.keys()	# return a list of all existing keys (slow!)
+
+Future versions may change the order in which implementations are
+tested for existence, add interfaces to other db-like implementations
+(e.g. BSD Hash), and (in the presence of multiple implementations)
+decide which module to use based upon the extension or contents of an
+existing database file.
+
+The open function has an optional second argument.  This can be set to
+'r' to open the database for reading only.  Don't pas an explicit 'w'
+or 'rw' to open it for writing, as the different interfaces have
+different interpretation of their mode argument if it isn't 'r'.
+"""
 
 try:
 	import dbm
-	def open(file, mode = 'rw'):
-		return dbm.open(file, mode, 0666)
+	def open(filename, mode = 'rw'):
+		return dbm.open(filename, mode, 0666)
 except ImportError:
-	import dbmac
-	open = dbmac.open
+	try:
+		import gdbm
+		def open(filename, mode = 'w'):
+			return gdbm.open(filename, mode, 0666)
+	except ImportError:
+		import dbmac
+		open = dbmac.open