1 # A wrapper around the (optional) built-in class dbm, supporting keys

     2 # and values of almost any type instead of just string.

     3 # (Actually, this works only for keys and values that can be read back

     4 # correctly after being converted to a string.)

     5 

     6 

     7 class Dbm:

     8 

     9     def __init__(self, filename, mode, perm):

    10         import dbm

    11         self.db = dbm.open(filename, mode, perm)

    12 

    13     def __repr__(self):

    14         s = ''

    15         for key in self.keys():

    16             t = repr(key) + ': ' + repr(self[key])

    17             if s: t = ', ' + t

    18             s = s + t

    19         return '{' + s + '}'

    20 

    21     def __len__(self):

    22         return len(self.db)

    23 

    24     def __getitem__(self, key):

    25         return eval(self.db[repr(key)])

    26 

    27     def __setitem__(self, key, value):

    28         self.db[repr(key)] = repr(value)

    29 

    30     def __delitem__(self, key):

    31         del self.db[repr(key)]

    32 

    33     def keys(self):

    34         res = []

    35         for key in self.db.keys():

    36             res.append(eval(key))

    37         return res

    38 

    39     def has_key(self, key):

    40         return self.db.has_key(repr(key))

    41 

    42 

    43 def test():

    44     d = Dbm('@dbm', 'rw', 0600)

    45     print d

    46     while 1:

    47         try:

    48             key = input('key: ')

    49             if d.has_key(key):

    50                 value = d[key]

    51                 print 'currently:', value

    52             value = input('value: ')

    53             if value is None:

    54                 del d[key]

    55             else:

    56                 d[key] = value

    57         except KeyboardInterrupt:

    58             print ''

    59             print d

    60         except EOFError:

    61             print '[eof]'

    62             break

    63     print d

    64 

    65 

    66 test()