Python serialize lexical closures?

Question

Is there a way to serialize a lexical closure in Python using the standard library? pickle and marshal appear not to work with lexical closures. I don\'t really care about

Answer 1

#!python

import marshal, pickle, new

def dump_func(f):
    if f.func_closure:
        closure = tuple(c.cell_contents for c in f.func_closure)
    else:
        closure = None
    return marshal.dumps(f.func_code), f.func_defaults, closure


def load_func(code, defaults, closure, globs):
    if closure is not None:
        closure = reconstruct_closure(closure)
    code = marshal.loads(code)
    return new.function(code, globs, code.co_name, defaults, closure)


def reconstruct_closure(values):
    ns = range(len(values))
    src = ["def f(arg):"]
    src += [" _%d = arg[%d]" % (n, n) for n in ns]
    src += [" return lambda:(%s)" % ','.join("_%d"%n for n in ns), '']
    src = '\n'.join(src)
    try:
        exec src
    except:
        raise SyntaxError(src)
    return f(values).func_closure




if __name__ == '__main__':

    def get_closure(x):
        def the_closure(a, b=1):
            return a * x + b, some_global
        return the_closure

    f = get_closure(10)
    code, defaults, closure = dump_func(f)
    dump = pickle.dumps((code, defaults, closure))
    code, defaults, closure = pickle.loads(dump)
    f = load_func(code, defaults, closure, globals())

    some_global = 'some global'

    print f(2)