This code pickles and unpickles functions. Note it is simi-hackish
and I make no guarentee about it working in python 3.0 (but I'll be
maintaining a copy for distributed stuff I'm working on for dev1.
import new, types, copy_reg, cPickle
#See python cookbook for more details
def code_ctor(*args):
return new.code(*args)
def reduce_code(co):
if co.co_freevars or co.co_cellvars:
raise ValueError, "Cannot pickle code objects from closures"
return code_ctor, (co.co_argcount, co.co_nlocals, co.co_stacksize, \
co.co_flags, co.co_code, co.co_consts, co.co_names, \
co.co_varnames, co.co_filename, co.co_name, \
co.co_firstlineno, co.co_lnotab)
copy_reg.pickle(types.CodeType, reduce_code)
def picklefunction(func):
return cPickle.dumps(func.func_code)
def unpicklefunction(pickled):
recovered = cPickle.loads(pickled)
ret = new.function(recovered, globals())
return ret
On Sat, Jun 14, 2008 at 11:25 AM, David Roe <[EMAIL PROTECTED]> wrote:
>
> One way to get around this limitation in python is to use callable
> classes instead of functions.
> David
>
> On Sat, Jun 14, 2008 at 10:42 AM, David Harvey
> <[EMAIL PROTECTED]> wrote:
>>
>> On Jun 14, 2008, at 1:25 PM, Daniel Bump wrote:
>>
>>
>> Some code that has been proposed by Nicolas Thiery
>> for sage/combinat/families.py would create classes
>> that have as attributes dictionaries of functions.
>> However dumps(s) will raise an exception if s is
>> such a class instance.
>> Example: the simple reflections in a Weyl group. See:
>> http://groups.google.com/group/sage-combinat-devel/msg/8b987cd471db3493?hl=en
>> What it boils down to is this. The following is
>> fine in native Python:
>>
>> import pickle
>> def f(x): return x+1
>>
>> ...
>>
>> pickle.dumps(f)
>>
>> 'c__main__\nf\np0\n.'
>>
>> pickle.dumps({1:f})
>>
>> '(dp0\nI1\nc__main__\nf\np1\ns.'
>> But if you try to run this from within Sage,
>> both calls to dumps() will raise exceptions.
>> Is this a bug in Sage?
>>
>> I actually thought you couldn't really pickle functions, even in plain
>> python.
>> http://docs.python.org/lib/node317.html
>> "Note that functions (built-in and user-defined) are pickled by ``fully
>> qualified'' name reference, not by value. This means that only the function
>> name is pickled, along with the name of module the function is defined in.
>> Neither the function's code, nor any of its function attributes are pickled.
>> Thus the defining module must be importable in the unpickling environment,
>> and the module must contain the named object, otherwise an exception will be
>> raised."
>> david
>>
>> >
>>
>
> >
>
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