summaryrefslogtreecommitdiffstats
path: root/Lib/copy_reg.py
blob: e4f0b3cfdac0e83b44a20809de9ce9c1be21cc24 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
"""Helper to provide extensibility for pickle/cPickle.

This is only useful to add pickle support for extension types defined in
C, not for instances of user-defined classes.
"""

from types import ClassType as _ClassType

__all__ = ["pickle","constructor"]

dispatch_table = {}
safe_constructors = {}

def pickle(ob_type, pickle_function, constructor_ob=None):
    if type(ob_type) is _ClassType:
        raise TypeError("copy_reg is not intended for use with classes")

    if not callable(pickle_function):
        raise TypeError("reduction functions must be callable")
    dispatch_table[ob_type] = pickle_function

    if constructor_ob is not None:
        constructor(constructor_ob)

def constructor(object):
    if not callable(object):
        raise TypeError("constructors must be callable")
    safe_constructors[object] = 1

# Example: provide pickling support for complex numbers.

def pickle_complex(c):
    return complex, (c.real, c.imag)

pickle(type(1j), pickle_complex, complex)